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Alpine Mass Movements: Implications for hazard assessment and mapping

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Inhalt

Wolfram Bitterlich:Wildbachverbauung und Ökologie Widerspruch oder sinnvolle Ergänzung?

Florian Rudolf-Miklau, Richard Bäk, Franz Schmid, Christoph Skolaut:Hazard Mapping for Mass Movements: Strategic Importance and Transnational Development of Standards in the ASP-Project ADAPTALP

Michael Mölk, Thomas Sausgruber, Richard Bäk, Arben Kociu:Standards and Methods of Hazard Assessment for Rapid Mass Movements (Rock Fall and Landslide) in Austria

Florian Rudolf-Miklau:Principles of Hazard Assessment and Mapping

Richard Bäk, Hugo Raetzo, Karl Mayer, Andreas von Poschinger, Gerlinde Posch-Trözmüller: Mapping of Geological Hazards: Methods, Standards and Procedures (State of Development) - Overview

Hugo Raetzo, Bernard Loup:Geological Hazard Assessment in Switzerland

Mateja Jemec & Marko Komac:An Overview of Approaches for Hazard Assessment of Slope Mass Movements

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Roland Norer:Legal Framework for Assessment and Mapping of Geological Hazards on the International, European and National Levels

Karl Mayer, Bernhard Lochner:Internationally Harmonized Terminology for Geological Risk: Glossary (Overview)BL

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Imprint / Disclosure

Federal Ministry of Agriculture, Forestry, Environment and Water Management, Marxergasse 2, 1030 Vienna, Austria.Verein der Diplomingenieure der Wildbach- und Lawinenverbauung, Bergheimerstrasse 57, 5021 Salzburg, Austria

Editorial Team:Florian Rudolf-Miklau, Richard Bäk, Christoph Skolaut and Franz Schmid

Coordination:Barbara Kogelnig-Mayer

Layout: Studio Kopfsache, Mondsee

Cite as:BMLFUW (2011): Alpine Mass Movements: Implications for hazard assessment and mapping, Special Edition of Journal of Torrent, Avalanche, Landslide and Rock Fall Engineering No. 166.

This publication was implemented within the framework of EU-project AdaptAlp, Workpackage 5, and is co-financed by the European RegionalDevelopment Fund (ERDF)

Cover picture: Großhangbewegung Rindberg, Gde. Sibratsgfäll, VorarlbergSource: die.wildbach

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Karl Mayer, Andreas von Poschinger:Standards and Methods of Hazard Assessment for Geological Dangers (Mass Movements) in Bavaria

Didier Richard:Standards and Methods of Hazard Assessment for Rapid Mass Movements in France

Pere Oller, Marta González, Jordi Pinyol, Jordi Marturià, Pere Martínez:Goeohazards Mapping in Catalonia

Marko Komac, Mateja Jemec:Standards and Methods of Hazard Assessment for Rapid Mass Movements in Slovenia

Karl Mayer, Bernhard Lochner:International Comparison: Summary of the Expert Hearing in Bolzano on 17 March 2010

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Claire Foster, Matthew Harrison & Helen J. Reeves: Standards and Methods of Hazard Assessment for Mass Movements in Great Britain Se

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Zusammenfassung:Massenbewegungen (Steinschlag, Rutschungen, Felsgleitungen) bedrohen den alpinen Lebensraum und verursachen zahlreiche Risiken. Durch die intensive Raumnutzung in den Bergtälern besteht ein zunehmender Bedarf an genauen Gefahrenkarten für diese Gefahren-arten. Aufgrund fehlender Daten und zuverlässiger Methoden für die Gefahrenbeurteilung wurden bisher keine generellen Standards für die Gefahrdarstellung von Rutschungen und Steinschlägen entwickelt. Die Unsicherheit in der Beurteilung der Gefahren wird durch den Einfluss des Klimawandels noch erhöht. Das Projekt ADAPTALP zielt darauf ab, diese Lücke durch die Entwicklung transnationaler Standards für die Gefahrenzonenplanung für Massen-bewegungen zu schließen.

“snow avalanches”. However there are no legal

(technical) standards available for the outline

of areas endangered by mass movements (e.g.

landslides, rock fall). The assessment of these

processes concerning the frequency and intensity

of events (disasters) is difficult and demanding

due to the lack of measurements and basic data.

In addition, the knowledge of geotechnical

parameters, physical properties and triggering

mechanisms of the displacement processes still

are fragmentary, although wide progress were

achieved by improved monitoring methods and

the detailed analysis of past events.

Recently the expansion of settlement areas

in Alpine valleys and the growing vulnerability of

human facilities have significantly increased the risk

for natural disasters caused by mass movements.

The growing demand for hazard maps that cover

these risky processes has initiated strong efforts in all

mountainous countries in Europe to develop exact

methods and appropriate standards that enable the

production of hazard maps for mass movements

with sufficient accuracy. By bundling these initiatives

the ASP (Alpine Space Program/Funding Initiative of

the European Commission) project ADAPTALP – in

cooperation with other projects like SAFELAND,

PERMANET or MASSMOVE – aims at the

development of technical standards and provision

of harmonized quality criteria for all member states.

Alpine Space at risk: Importance of hazard maps

In the Alpine countries, natural hazards constitute

a security risk in many regions. Floods, debris

flows, avalanches, landslides and rock falls

threaten people, their living environments, their

settlements and economic areas, transport routes,

supply lines, and other infrastructure. They

constitute a major threat to the bases of existence

of the population. The increasing settlement

pressure and area consumption, the opening up

of transport routes in the Alps as well as strong

growth rates in tourism have brought about a

considerable spatial extension of endangered

areas. With the rising demands on welfare and

quality of life, the need for safety and protection

of the population increased as well.

Hazard maps that show areas at risk by natural

hazards are of paramount importance for the

development of Alpine regions. The maps count

among the active planning measures in natural

hazard management and serve to the safety of

existing settlements and their inhabitants as

well as to the steering of land-use only outside

of endangered areas. Since the beginning of

1970’s, these maps have been established in

several countries (Switzerland, Austria, France)

for the hazards “flood”, “debris flow” and

Hazard Mapping for Mass Movements: Strategic Importance and Transnational Development of Standards in the ASP-Project ADAPTALP

Gefahrendarstellung von Massenbewegungen: Strategische Bedeutung und länderübergreifende Entwicklung von Standards im Projekt ADALPTALP

Summary:Mass movements (rock falls, landslides, rock slides) are major threats for the Alpine living space and cause various risks. Due to the intensive land use in the mountain valleys, there is an urgent need for reliable hazard maps for these types of hazards. Missing data and the lack of reliable methods for the assessment of hazards has obstructed the development of general standards in hazard mapping for landslides and rock fall. The uncertainties and inaccuracies of models are increased by the impact of climate change. The project ADAPTALP (within the Alpine Space Program) aims to close this gap by creating transnational standards for hazard mapping concerning geological risks (mass movements).

FLORIAN RUDOLF-MIKLAU, RICHARD BÄK, FRANZ SCHMID, CHRISTOPH SKOLAUT

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of the particles. Slopes consisting of silt and clay

particles obtain it from particle cohesion, which is

controlled by the availability of moisture in the soil.

Rock slopes generally have the greatest internal

strength due to the crystalline structures.

Instability is not always caused by an

increase in stress. In some cases, the internal

strength of the materials can be reduced resulting

in the triggering of a mass movement. Failure of

the slope material can occur over a range of time

scales. Some types of mass movement involve

rather rapid, spontaneous events. Sudden failures

tend to occur when the stresses exerted on the

slope materials greatly exceed their strength for

short periods of time. Mass movement can also

be a less continuous process that occurs over long

periods of time. Slow failures often occur when

the applied stresses only just exceed the internal

strength of the slope system.

Many factors can act as triggers for slope

failure. One of the most common is prolonged

or heavy rainfall. Rainfall can lead to mass

movement through three different mechanisms.

Often these mechanisms do not act alone. The

saturation of soil materials with water increases

the weight of slope materials which then leads

to greater gravitational force. Saturation of soil

materials can also reduce the cohesive bonds

between individual soil particles resulting in the

reduction of the internal strength of the slope.

Lastly, the presence of bedding planes in the slope

material can cause material above a particular

plane below ground level to slide along a surface

lubricated by percolating moisture.

Additionally, a large variety of other

trigger mechanism for mass movement other than

the gravitational are known, such as:

• Earthquake shocks cause sections of

mountains and hills to break off and slide

down.

• Human modification of the land or

weathering and erosion help loosen large

chunks of earth and start them sliding

downhill.

• Vibrations from machinery, traffic, weight

loading from accumulation of snow,

stockpiling of rock, from waste piles and

from buildings and other structures.

In the Alps, mass movements occur in a wide

range of processes consisting of bedrock and soil

or a mixture of both.

Mass movement on hard rock slopes

is often dramatic and quick. They involve the

downward movement of small rock fragments

pried loose by gravitational stress, the enlargement

of joints during weathering and/or freeze-thaw

processes (rock fall). Larger scale, down slope

movement of rock can also occur along well-

defined joints or bedding planes. This type of

movement is called rock slide. Rock slides often

occur when a fracture plane develops causing

overlying materials to slide down slope.

Slopes formed from clays and silt

sediments display somewhat unique mass

movement processes. Two common types of

mass movements in these cohesive materials are

rotational slips (slumps) and mudflows. Both of

these processes occur over very short time periods.

Rotational slips or slumps occur along clearly

defined planes of weakness which generally have

a concave form beneath the earth's surface. These

processes can be caused by a variety of factors.

The most common mechanical reason for them

to occur is erosion at the base of the slope which

reduces the support for overlying sediments.

Mudflows occur when slope materials become

so saturated that the cohesive bonds between

particles is lost. In a mudflow there is enough

water to allow the mixture to flow easily, as a

viscous stream. Mudflows can occur on very low

slope angles because internal particle frictional

resistance and cohesion is negligible.

damming up bodies of water. Expenses related to

landslides include actual damages to structures

or property, as well as loss of tax revenues on

devalued properties, reduced real estate values

in landslide prone areas, loss of productivity of

agricultural lands affected by landslides, and loss

of industrial productivity because of interruption

of transportation systems by landslides. Not only

rapid types of mass movements are harmful.

Slow movement of creep does more long term

economic damage to roads, railroads, building

structure and underground pipes.

The operation of mass movement

processes relies upon the development of

instability in the slope system. The predominant

source of stress is the gravitational force. Other

factors that affect mass movements are the

steepness of slopes, the lithological property of

the slope materials, and the amount of water in

the material. The two most important parameters

in mass movement is the angle of friction and the

cohesion.

The magnitude of the gravitational

force is related to the angle of the slope and the

weight of slope sediments and rock. The following

equation models this relationship:

The stability of a slope depends on the

relationship between the stresses applied to the

materials that make up the slope and their internal

strength. Mass movement occurs when the stresses

exceed the internal strength. Slopes composed of

loose materials, such as sand and gravel, derive

their internal strength from frictional resistance,

which depends on the size, shape, and arrangement

Mass movements: Hazard processes on slopes

A variety of processes exist by which materials

can be moved through the slope system. These

processes are generically known as mass

movement or mass wasting. Mass movements

per definition are movements of bodies of soil,

sediments such as residual soil and bed rock

which usually occur along steep-sided slopes and

mountains. Mass movements can be classified

due to the rate of movement (rapid or slow), the

type of movement (falling, sliding or flowing) and

to the type of material involved (soil, sediments or

rock debris).

Mass movements have direct and

indirect impact on a number of human activities.

The steepness and structural stability of slopes

determines their suitability for agriculture, forestry,

and human settlement. Instable slopes can also

become a hazard to humans if their materials

move rapidly through the process of mass wasting.

Landslides can suddenly rush down a steep slope

causing great destruction across a wide area

of habitable land and sometimes also floods by

Fig. 1: Land slide in cohesive soil resulting from slope instabilities and saturation of material by water.

Abb. 1: Rutschung in bindigem Boden resultierend aus Hanginstabilitäten und Wassersättigung des Bodens.

F = W sin Ø

where

F is gravitational force,

W is the weight of the material occurring at

some point on the slope, and

Ø is the angle of the slope.

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Hazard maps for mass movements

Hazard zones are designated areas threatened

by natural risks such as avalanches, landslides or

flooding. The formulation of these hazard zones is

an important aspect of spatial planning. The basis

for hazard maps is a comprehensive assessment

of geological and hydro(geo)logical framework

conditions, slope instabilities, relevant triggering

mechanisms, properties of displacement

processes, potential risks and the vulnerability

of endangered areas (objects). Consequently it is

essential to distinguish the three aspects of mass

movement assessment and mapping:

• Dangers (susceptibilities): Assessment

and characterization of threat (typology,

morphology, inventory of mass movements).

• Hazards: Spatial and temporal probability,

intensity and forecasting of evolution

(scenarios) are needed.

• Risks: Interaction between a threat having

particular hazard and human activities.

In principle, these theoretical concepts are well

known by experts but

may cause problems in

practice when applied

in a legal framework.

It is not unusual for

unsuitable types of

hazard maps to be

applied for the wrong

purposes. For example

it is often to find

landslide inventory

maps used as hazard

or risk maps.

When mapping

geological hazards

(mass movements) in

principle we have to

distinguish between two situations:

1. Scientific studies on mass movements with no

legal implications (e.g. on land use planning):

Typical cases are studies carried out by

universities (research institutes). The aim of

these studies is to understand the mechanical

features of instability or to study different ways of

evolution of the phenomenon (scenarios) in order

to assess the susceptibility of investigated areas.

Landslide inventories can be made by means of

a historical or morphological approach.

2. Susceptibility/Hazard index/Hazard maps that

have direct (obligatory) consequences for land

use planning and building trade at different

scale: The scale used to present the results of

the hazard assessment depends on the desired

product (susceptibility map, hazard index map,

hazard zone map) and must be balanced with

the precision requirements according to the

spatial level of application (supra-regional,

regional, local). The legal significance of these

maps requires technical standards and a “state-

of-the-art” concerning formal requirements

(e.g. investigation methods, documentation),

Fig. 2: Transnational standards in hazard mapping are of major importance for the prevention of catastrophic events according to land use in endangered areas.

Abb. 2: Die Entwicklung von länderübergreifenden Standards in der Gefahrendarstellung ist bei der Prävention von Katastrophenereignissen von großer Bedeutung, da gefährdete Gebiete immer stärker genutzt werden.

to the increasing temperatures. The uncertainties

and the increase of natural hazards due to the

impacts of climate change require concerted

management in the Alpine Space. It must be

managed on a transnational, national, regional

and local scale to effectively save human life,

settlements and infrastructure. Nevertheless, there

is still a lack of precise data taking climate change

into account. The result is an insufficient accuracy

of available models and inaccurate prediction of

natural hazard and menacing catastrophic events.

The impact of climate change increases these

uncertainties.

Harmonized cross-sectoral hazard

assessment and hazard mapping must be balanced

on a transnational level. The ADAPTALP project

(www.adaptalp.org) focuses on the harmonization

of the various national approaches and methods

for the assessment of hazards related to mass

movements. Along with the harmonization

of terminology, an important issue tackled by

ADAPTALP is the provision of reliable data and

models for this kind of processes. The more

reliable the information basis, the more efficiently

adaptation strategies on local and regional level

can be implemented. The project is based on an

integrated transnational approach. That means

that a comprehensive comparison of all available

standards and methods is carried out covering all

countries in the Alpine region (Austria, Germany,

Italy, France, Switzerland, Slovenia) and other

European states with a considerable share of

mountain regions (Great Britain, Spain, Norway).

The transnational exchange of knowledge and

the international harmonization in method and

procedure will raise the quality of hazard assessment

considerably. A general “state-of-the-art” for hazard

mapping concerning mass movements seems to be

within reach.

An earth flow is slower moving than a mudflow

and involves a mass of material that retains rather

distinct boundaries as it moves. “Debris flow” is

a term used generally for rapid mass movements

consisting of water and residual soil. The term

implies a heterogeneous mixture of materials

including a considerable fraction of particles

that are coarser than the particles in mud. Debris

flows occur on slopes as well as in laterally

confined channels.

ASP-project ADAPTALP: Adaptation of

natural hazard management to climate change

Climate change is, to a large extent, constituted by

increasing temperatures and changed precipitation

patterns. Any change of these critical factors

has implications on the frequency and extent of

natural hazards including mass movements. A

major impact on the intensity of mass movements

at high altitudes (above 2300 m in the Alps) has

thaw of permafrost and the retreat of glaciers due

Tab. 1: Types of mass movements (classification) after Raetzo.

Tab. 1: Typen von Massenbewegungen (Klassifikation)

Type BedrockEngineering soil predominantly …

… coarse … fine

FallRock fallRock avalanche

(Debris fall) (Earth fall)

Topple Rock topple

(Debris topple) (Earth topple)

Slide Rock slide Debris slide Earth slide

Spread Rock spread

(Debris spread) (Earth spread)

Flow (Rock flow)

Debris flow (in channels) Earth flow

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Anschrift der Verfasser / Authors’ addresses:

DI Dr. Florian Rudolf-Miklau

Bundesministerium für Land- und Forstwirtschaft,

Umwelt und Wasserwirtschaft,

Abteilung IV/5, Wildbach- und Lawinenverbauung

Federal Ministry for Agriculture, Forestry,

Enviroment and Water Management,

Department IV/5, Torrent and Avalanche Control

1030 Wien, Marxergasse 2

Tel.: (+43 1) 71 100 - 7333

FAX: (+43 1) 71 100- 7399

Mail: florian.rudolf-miklau@lebensministerium.at

Homepage: http://www.lebensministerium.at/forst

Dr. Richard Bäk

Amt der Kärntner Landesregierung, Abt. 15 Umwelt

Unterabteilung Geologie und Bodenschutz,

A – 9020 Klagenfurt, Flatschacher Straße 70

Tel: +43 - (0) 50536 - 31510

Fax: +43 - (0) 50536 - 41500

Mob. +43 - (0) 664 - 8053631510

Mail: richard.baek@ktn.gv.at

DI Franz Schmid

Bundesministerium für Land- und Forstwirtschaft,

Umwelt und Wasserwirtschaft,

Abteilung IV/5, Wildbach- und Lawinenverbauung

Federal Ministry for Agriculture, Forestry,

Enviroment and Water Management, Department

IV/5, Torrent and Avalanche Control

1030 Wien, Marxergasse 2

Tel.: (+43 1) 71 100 - 7338

FAX: (+43 1) 71 100- 7399

Mail: franz.schmid@lebensministerium.at

Homepage: http://www.lebensministerium.at/forst

DI Christoph Skolaut

Wildbach- und Lawinenverbauung,

Sektion Salzburg

Torrent and Avalanche Control, District Salzburg

5020 Salzburg, Bergheimerstraße 57

Tel.: (+43 662) 871853 – 303

FAX: (+43 662) 870215

Mail: christoph.skolaut@die-wildbach.at

Homepage: http://www.lebensministerium.at/forst

Literatur / References:

BATES A. L., JACKSON J. A.: Glossary of Geology. American Geological Institute, 3rd Edition, 1987.

CAMPUS S., BABERO S., BOVO S., FORLATI F. (EDS.): Evaluation and prevention of natural risks. Taylor and Francis/Balkema, 2007.

GLADE T., ANDERSON M., CROZIER M. J. (HRG.): Landslide Hazards and Risk. John Wiley & Sons, Chichester, 2005.

GRUNER U., WYSS R.: Anleitung zur Analyse von Rutschungen. Swiss Bull. angew. Geol., Vol. 14/1+2, 2009.

RAETZO, H. , RICKLI, C.: Rutschungen. In: Bezzola G.R, & Hegg, C. (Hrsg.) 2007: Ereignisanalyse Hochwasser 2005, Teil 1 – Prozesse, Schäden und erste Einordnung. Bundesamt für Umwelt BAFU, Eidgenössische Forschungsanstalt WSL. Umwelt-Wissen Nr. 0707, 2007.

RUFF, M.: GIS-gestützte Risikonanalyse für Rutschungen und Felsstürze in den Ostalpen (Vorarlberg, Österreich). Georisikokarte Vorarlberg. Diss. Univ. Karlsruhe, 2005.

SIDLE R. C., OCHIAI H.: Landslides processes, prediction and land use. American Geographical Union, water resources monograph 18, Springer Verlag, 2006.

a climate change adaptation strategy. The results

will be summarized in a synthesis report.

These fields of research within the

project contain the topics to work out the

“minimum standards” (minimal requirements) for

the creation of danger (susceptibility) and hazard

maps for landslides. The first step is the evaluation

of the “state of the art” in hazard mapping in each

involved country. Two main questions will be

answered by the project:

• What kinds of danger (susceptibility),

hazard and risk maps are officially applied

in each country?

• Which standards are these maps based on?

The second step will be the “harmonization” of

the different methods, which are used in several

countries. Therefore similarities should be worked

out and the “least common denominator” in the

methods of hazard mapping should be found.

The final step will be the creation of guidelines

and recommendation, which include the results

of this “harmonization”. They will include

“minimum requirements for the creation of danger

(susceptibility), hazard and risk maps”.

Other important results – developed in cooperation

with other projects as MASSMOVE – will be:

• Definition of minimal requirements for the

collection of the relevant data of endangered

areas and cartographic representation of

slides and rock falls.

• Specification of minimal requirements for

the spatial description of the dangers.

• Development of minimal requirements for

the determination of the hazard potential of

slides and rock falls.

• Development of tools for the reduction of

the risk potential by consideration of the

hazards during land use planning by the

local administrations and during the land

use as well as for the planning of preventive

measures.

hazard assessment and procedures of the check

and approval of the maps.

ADAPTALP (in Work Package 5) will

evaluate, harmonize and improve different

methods of hazard mapping applied in the Alpine

area. A main emphasis will be on a comparison

of methods for mapping geological hazards in

the individual countries. A glossary will facilitate

interdisciplinary and multilingual cooperation as

well as support the harmonization of the various

methods. In selected model regions methods

to adapt risk analysis to the impact of climate

change will be tested. This should support the

development of hazard zone planning towards

Fig. 3: Example for a susceptibility map of the Arlberg region (Vorarlberg/Austria) after Ruff

Abb. 3: Beispiel einer Suszeptibilitätskarte der Arlbergregion (Vorarlberg/Österreich) nach Ruff

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According to the well-established basic concept of

hazard assessment, the procedure can be divided

in three distinct steps (HÜBL ET AL., 2007 [9.]:

• The survey of basic information (data)

• The analysis of hazards (and risks)

• The valuation of hazards (and risks)

As a rule, the survey of information related to

natural hazards focuses on the acquisition of

basic data on relevant factors in nature. The survey

includes “geo-data” (topography, geology, and

soil), “meteo-data” (climate, weather), “hydro-

data” (precipitation, run-off, and groundwater)

and “eco-data” (environmental parameters). In

addition, data on past (historic) events represent a

major source of information. (RUDOLF-MIKLAU,

2009 [14.]) For the purpose of risk assessment,

data for natural processes must be combined with

data related to human activities. These sources of

information include demographic and economic

statistics, data on land use and agriculture,

and records of damages caused by past events

(BRÜNDL ET AL., 2009 [5.]).

Basic concept of hazard assessment

Effective prevention against natural hazards

requires a better understanding of the processes

occurring in nature. The primary aim of hazard

assessment is to gain a deep and comprehensive

knowledge of these processes in order to provide

accurate prognosis of the expected magnitude

of hazardous events and the corresponding

damaging effects. (RUDOLF-MIKLAU in SUDA

ET. AL., 2011 [18.]) Another important demand

is the prediction of the time of occurrence and

duration of a catastrophic event (predictability

and advanced warning time; Fig. 1) (RUDOLF-

MIKLAU, 2009 [14.]). The initial purpose of

hazard assessment is the provision of basic

knowledge for the planning of protection

measures (e.g. flood control, avalanche control),

which requires quantitative information about

the order and magnitude of catastrophic events

and their probable damaging consequences on

human health, economic activities, environment,

and cultural heritage.

seconds

Earthquake

Rockfall

Debris flow

Avalanches

Landslides

Floods

Storm

Wildfire

Drought

Volcanism

Deceases

Advanced warning time(T)

Pred

icta

bilit

y

minutes hours days weeks

Fig. 1: Predictability of natural hazards (RUDOLF-MIKLAU, 2009 [14.]).

Abb. 1: Vorhersagbarkeit von Naturgefahren (RUDOLF-MIKLAU, 2009 [14.]).

Principles of Hazard Assessment and Mapping

Grundlagen der Analyse und Bewertung von Naturgefahren

Summary:The article summarizes the general principles for the assessment of natural hazards. The main emphasis lies on the basic approaches and methods of hazard assessment with special attention to the “frequency-intensity-concept” (including the deficits of this approach). The strategic importance of “preventive” planning with regards to the use and development of endangered areas in mountain areas is discussed. In addition, a summary of the most impor-tant standards and categories of hazard (risk) mapping is provided.

Zusammenfassung:Der Beitrag fasst die generellen Grundlagen der Analyse und Bewertung von Naturgefahren zusammen. Der Schwerpunkt liegt im Bereich der grundlegenden Ansätze und Methoden für die Gefahrenbewertung, wobei das „Häufigkeits-Intensitäts-Konzept“ besondere Beachtung findet (einschließlich der Defizite dieses Ansatzes). Weiters wird auf die strategische Bedeu-tung der „präventiven Planung“ hinsichtlich der Nutzung und Entwicklung von gefährdeten Gebieten im Gebirge eingegangen. Abschließend erfolgt eine zusammenfassende Darstel-lung der wichtigsten Standards und Kategorien der kartographischen Darstellung von Natur-gefahren.

FLORIAN RUDOLF-MIKLAU

Key-note papers

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regionally measurements and data from

documented events ahead of application.

• The application of physical models is not

only performed for one single data set but

for a frequency range of the input values.

• Scenarios are checked concerning their

plausibility.

Approaches to hazard assessment: The “frequency-

magnitude-concept” for design events (DE)

According to ONR 24800:2008 [13.] an event

represents the entirety of all processes occurring

in a temporal, areal and causal relationship and

corresponds to a specific probability of recurrence

and intensity. The extreme event represents the

maximum magnitude observed in the concerning

catchment or risk area. The design event (DE)

is applied as reference value (criteria) for the

planning of protection measures and hazard

maps and represents the striven level of safety

(acceptable risk). (RUDOLF-MIKLAU, 2009 [14.])

The underlying concept of intensity and

frequency was originally established by WOLMAN

& MILLER (1960) [19.]. Intensity in colloquial use

refers to strength or magnitude of a process or

event. Intensity of natural events (hazards) can be

expressed by physical criteria like discharge, flow

depth, pressure (process energy) or area (mass)

of deposited debris. (GEBÄUDEVERSICHERUNG

GRAUBÜNDEN, 2004 [7.]) In general the

frequency represents the period of recurrence

between two events with comparable magnitude.

Frequency is often expressed as return period,

which is equal to the reciprocal of the exceedance

probability of extreme precipitation or discharge

values. As a rule the DE is determined according

to a defined return period (e.g. flood with return

period of 100 years). Frequency and intensity are

functionally correlated. (RUDOLF-MIKLAU in

BOLLSCHWEILER ET AL., 2011 [3.])

The frequency-intensity-concept is based

on extreme value statistics and is appropriate for

answering two basic questions:

• How often does an extreme event of

defined intensity occur statistically?

• What is the expected extreme value for a

defined time period?

The two established methods to analyse extreme

events are the “block-maxima-method” and

the “peak-over-threshold-method” (KLEEMAYR

in RUDOLF-MIKLAU & SAUERMOSER, 2011

[16.]). For the statistic analysis, random and

representative samples (data sets) are needed

(e.g. time series of extreme precipitation). By

means of statistical methods, it is attempted to

conclude from properties of the sample to the

rules of the “total population”. In technical terms,

an unknown stochastic distribution function (e.g.

Gumbel, Fréchet, Weibull) is derived from an

empirical distribution of measured values. The

most common field of application of the extreme

value statistics is the prediction of weather

extremes, extreme discharge in rivers and torrents

of the extreme run-out distance of falls, slides or

falls (mass movements or avalanches). The key

problem of the method is the limited availability of

measurements (data sets) that cover a sufficiently

long period of time. In most cases the available

data represents

• either a too short observation (measuring)

period,

• or is fragmentary

or both. Besides this major disadvantage, the

method of extreme value statistics shows other

considerable short comings.

Especially for torrential processes, the frequency-

intensity-function shows an “emergent” behavior

implying a limited predictability of discharge

from extrapolations of measurement data when

a certain threshold value is exceeded. The event

disposition of a catchment or risk area, defined

Key-note papers

method for most natural hazards in order to value

their effects (see below). (HÜBL, 2010 [8.])

Natural hazards in the Alpine

environment are a complex system consisting

of process chains with multiple interactions

and dependencies. Thus the assessment of a

hazard is not a mono-causal procedure but

must take into account a large variety of more

or less probable courses. (RUDOLF-MIKLAU

in BOLLSCHWEILER ET AL., 2011 [3.]) The

“scenario analysis” was established in risk

management as an appropriate method to

solve the complexity of comprehensive hazard

assessment. Scenarios implicate that not only a

single process but all relevant developments of

an event within a defined period of recurrence

are taken into account. (MAZZORANA ET AL.,

2009 [12.]) In practice this means:

• Several assessment methods (e.g.

morphologic, historic, stochastic) are

applied.

• Models have to be calibrated with

The analysis of hazards is subdivided into several

tasks: the survey and localization of hazard

sources, the identification of triggering factors,

the description of the triggering and displacement

process and the potential effects (impact) on

objects. The results of the hazard analysis are

usually mapped in specific types of hazard maps

(e.g. susceptibility maps, intensity maps).

The analysis of natural hazards provides a

comprehensive image of the processes, their causes

and effects, but requires additional information

concerning the order of magnitude of the relevant

event. (RUDOLF-MIKLAU in BOLLSCHWEILER

ET AL., 2011 [3.]) Consequently, the valuation of

hazards aims at the description of magnitude in a

graded manner. Hazards scales, physical intensity

criteria or intensity classifications count among

the established methods to present the magnitude

of events. Usually the intensity of a hazardous

process is functionally related to the frequency

of its occurrence. In practice this “frequency-

intensity-concept” is the preferentially applied

RISKSHAZARDS

Risk analysisAnalysis of damages: direct/indirect damageDamage potentialDamage scenarios

Hazard analysisLocalization and topographyTriggering mechanismDisplacement processes/scenariosFrequency/intensitiy

Risk managementDefinition of protection goalsCreation of protection conceptsManagement plansProtection measuresEffectiveness / Efficiancy

Hazard assessmentLevels of hazard (risk)Classification of intensityIntensity criteria: e.g. pressure

Risk assessmentValidation of risksRisk acceptance (aversion)

Risk mapCartographical presentation of risks

Process-/Suszeptibility maps

Hazard (information) maps

Hazard zone maps

Man

agem

ent

Pres

enta

tion

Valid

atio

nSu

rvey

Fig. 2: System of hazard and risk management (RUDOLF-MIKLAU/SAU-ERMOSER, 2011 [16.]).

Abb. 2: System des Gefahren- und Risikoma-nagements (RU-DOLF-MIKLAU/SAUERMOSER, 2011 [16.]).

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hazard assessment is the compliance of a high

redundancy in the procedures and methods applied

(KIENHOLZ, 2005 [10.]). Two principle approaches

are eligible for hazard assessment (Fig. 3):

• The analysis of past events (retrospective

indication).

• The prognosis of future events (foresighted

indication).

According to these principles, the following

procedures can be chosen and should be

applied corresponding to the rule of redundancy

(HÜBL et al., 2007 [9.]):

Historical Method: The method is based

on the (qualitative and quantitative) analysis of

reports, testimonies and chronicles of past events

(catastrophes). This data provides evidences

for the frequency of events, the triggering

mechanism and the extension of the process as

well as the damages occurred. As a rule, historic

sources tend to be fragmentary and distorted due

to subjective perception.

Morphological Method: This method

is based on the identification of triggering/

displacement processes and the spatial distribution

by means of “silent witnesses” (AULITZKY, 1992

[1.]) in the morphology (deposition area) and at

the vegetation (e.g. trees). Dendromorphology

counts among these methods, which (besides

other dating methods (BOLLSCHWEILER ET. AL.,

2011 [3.])) provides

comprehensive time

series of past events.

Statistical Method:

This method includes

the analysis of

m e a s u r e m e n t s

and observation

(monitoring) data by

means of stochastic

methods (e.g. extreme

value statistics).

Nevertheless, the

derivation of reliable

(significant) trends

and prognoses

requires a sufficient

quantity of data for

a representative

time (observation)

period. (KLEEMAYR in RUDOLF-MIKLAU &

SAUERMOSER, 2011 [16.])

Physical/Mathematical Method: These

methods are mainly based on numerical or

empirical models, which provide information

(physical criteria) for the intensity of an event

for a defined return period. In practice models

are the preferred tool for the determination of

design events in natural hazard engineering. Due

to the limited accuracy of numerical models, the

application always presupposes a calibration of

regional measurements (data) and the validation

of the results with expert opinions. In addition,

Key-note papers

Historical Methodchronicles, witnesses

Morphological Method„silent witnesses“, dendromophology

is based on the assumption, that an occured eventwill reoccur with comparable course and effects.

is based on the identification and analysis of factorsand processes, which represent evidence for existing hazards according to gained experiences.

The method presupposes knowledge about the triggering mechanism, the displacement processand the effect (impact) and includes theinvestigation of probability of recurrence(return period).

Statistical Methodextreme value statistics, triggering

mechanism

Pragmatic MethodExpert opinion (estimation)

Physical/MathematicalMethod

Numerical/empirical models

Retrospective Indication

Foresightes Indication

Fig. 3: Principle approaches to hazard assessment (after KIENHOLZ, 2005 [10.]; modified).

Abb. 3: Grundlegende Vorgehensweisen bei der Gefährdungsanalyse (nach KIENHOLZ, 2005 [10.]; geändert).

floods can approximately be related to a certain

return period. A causal supplement of information

is gained if observed floods are analyzed with

respect to their emergence regarding the weather

conditions, the behavior of precipitation, and the

disposition of the catchment area.

In a first step, the determination procedure

of the design flood requires the specification of

the expected value of discharge by means of flood

statistics and additional hydrological methods.

From this basic design discharge, the design

flood can be derived by taking into account solid

transport, transient flow conditions and influences

of stream morphology.

The applicability of the frequency-

intensity-concept is strongly limited for all types of

hazards for which measurements or observation

data of extreme events are insufficiently or

generally not available. In addition, it has to be

taken into account that the period of recurrence of

a triggering event can significantly differ from the

frequency of the impact (damage) event. Recently,

alternative concepts for the assessment of

magnitude of events are sought that could replace

the “frequency-intensity-concept”. This holds

especially true for the assessment of extreme mass

movements and avalanches where frequency

hardly can be determined with sufficient accuracy.

Methods of hazard assessment

The aim of hazard assessment is the determination

of relevant scenarios and the related return period

for the purpose of providing a prognosis of the

substantial process, the extension and intensity of

an event as well as for the magnitude of hazard

(BRÜNDL ET AL., 2009 [5.]).

Normally neither the physical properties

of hazard processes are completely clarified, nor

is sufficient data on extreme events available.

Consequently, the most important principle of

as the entirety of all conditions essential for the

emergence of hazardous processes, consists of the

basic disposition (susceptibility) comprising all

factors immutable over a long range of time (e.g.

geology, soils) and the variable disposition, which

is the sum of all factors subject to a short-term or

seasonal change (e.g. precipitation, saturation of

soil with water, land use). If the variable disposition

of a catchment or risk area is altered in the course

of an event (e.g. exceedance of the water storage

capacity of soil), the debris potential increases

erratically, resulting in a possible transition of the

predominant displacement process and a non-

linear increase of discharge. (HÜBL, 2010 [8.])

The practical procedure of specification

of a design event can be lucidly explained by the

example of a “design flood” (RUDOLF-MIKLAU &

SEREINIG, 2010 [15.]): Generally, a design flood

[discharge in m³/s] with a return period of 100

years represents the striven level of safety for flood

(torrent) control measures in European countries.

Expected values for a rainfall and flood events of a

defined return period (including a corresponding

confidence interval) can be derived from the

hydraulic extreme value statistics. Flood statistics

are based on the assumption that the observation

period is representative for the long-term runoff

behavior of the watershed. However, extreme

flood events are qualified as “statistical outliers”

that are not represented by the measured data

collection (due to limited observation periods),

but nevertheless contribute valuable information

on hydrological extremes. Consequently, the

statistically deduced design criterion should be

supported by additional information of temporal,

spatial or causal reference. Especially the dating

of historic flood events from chronicles or traces

in nature (flood marks, “silent witnesses”) can

provide precious additional information on

return periods, levels of flooding, or peak flood

discharge. By dating historic events, extreme

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storm, forest fire, snow load), preventive planning

is limited to rough-scale maps showing a general

gradation of risks. (RUDOLF-MIKLAU, 2009 [14.])

The environmental planning is of major

importance for the application of hazard maps.

Consequently, preventive planning can be

understood as a part of development planning.

In order to regulate the use and development of

endangered areas, the intervention of the state

is essential. The primary goal of development

planning concerning natural hazards is to keep

the endangered areas free from buildings (passive

protection function). The active protection function

of preventive planning lies in the reservation

(provision) of areas for the spreading of hazardous

processes (e.g. inundation areas) or in the provision

of standards (limits) for the use of endangered areas

in order to reduce the risk potential.

Mapping hazards in Alpine environment

The cartographic outline of endangered areas

according to KIENHOLZ (2005) [10.] includes the

elaboration of scientific and technical bases and

the depiction in hazard (indication) maps. In a

second step, the geographic information provided

on triggering disposition and impact intensity of

hazardous processes is used for the provision

of hazard zone maps and their implementation

in the process of development planning. As a

rule, hazard maps have no legal liability but are

defined as “spatial expert opinions with prognosis

character”, while the hazard zones become

legally binding only by incorporating them into

development planning documents (land use

maps). Thus legal liability of hazard zones may

arise on the local level depending on the national

legal framework.

Consequently, it is essential to adapt the

standards of hazard mapping to the requirements

and goal of development planning on the regional

and local level. In the Alpine countries in general

the following categories of maps for the outline of

hazards and risks can be distinguished:

• Process maps (susceptibility, intensity)

• Hazard (indication) maps

• Hazard zone maps

• Risk maps

The following definitions are valid only with

restrictions since terminology of hazard mapping

substantially differs between countries and

scientific branches.

A hazard (indication) map roughly

indicates in which areas natural hazard have to be

taken into account in land use and development

activities. The character of the map is only

demonstrative, while no concrete information

about the magnitude of the danger is provided.

In many countries hazard zone maps are not

available, leaving hazard indication maps as the

only source of spatial information.

Process maps show hazards by the

spatial distribution of physical parameters

(criteria) describing the triggering, displacement

and impact processes. These maps are most often

the result of numerical or empirical modeling. In

some countries, process maps are transformed

into intensity maps showing the process criteria

graded according to the levels of impact intensity

(e.g. Switzerland: frequency-intensity-matrix;

LOAT, 2005 [11.]). Susceptibility is defined as the

extent to which an area suffers from the risk of

emergence of a hazardous process if exposed to a

triggering factor, without regard to the likelihood

of exposure. Analogously, susceptibility maps

show the disposition of an area for these events,

but does not provide information about the

frequency and expected intensity.

Hazard zone maps show the impact of

processes according to its magnitude (intensity,

frequency) on the scale of the local cadastre

(1.2000 – 1.5000). Consequently, these

Key-note papers

Preventive planning: principles and function

“Prevention by planning” today is qualified as

the most effective measure in natural hazard

management. Planning in relation to natural

hazards and risks can also unfold active as

passive protection effects. Planning procedures

concerning natural hazards are not limited to the

cartographic outline of endangered areas (areas

at risk), but also provide the passivity to reduce

hazards/risk by keeping endangered areas free

from buildings or limiting the use of these zones

(e.g. inundation areas). Thus preventive planning

is the basis for the protection strategy “prevention

by area”. (RUDOLF-MIKLAU, 2009 [14.])

In addition, the cartographic depiction of

hazard zones provides the essential information

(process intensity, magnitude of impact forces)

for the technical protection of existing buildings.

Also the suitability of planned building sites

concerning the risk by natural hazards can be

efficiently judged on the basis of hazard maps.

In development planning, the localization of new

settlements can be steered away from impending

hazards. (BUWAL/BRP/BWW, 1997 [6.])

In principle, in the Alpine environment

the usability of land for building purposes is

limited according to the expansion of hazards.

In mountainous regions, the total avoidance

of hazard zones for spatial development is not

possible. Consequently, preventive planning

defines limits (border lines) for areas that are

appropriate for building. Within these limits,

hazard maps provide bases for standards and

regulations for a hazard-adapted construction

practice.

Logically, the main emphasis of preventive

planning lies in the sector of hazards spatially

“delimited” in action, such as floods, avalanches,

mass movements. For natural hazards that do not

allow an “exact” delimitation (e.g. earthquake,

models should not only be applied for a single

data set but for a range of scenarios as well as for a

distribution of input parameters. A comprehensive

summary of available models for torrential

processes is given in BERGMEISTER ET AL. (2009)

[2.], for avalanches in RUDOLF-MIKLAU &

SAUERMOSER (2011) [16.].

Pragmatic Method: This method is

based on the “expert opinion” of experiences

practitioners and local experts. The pragmatic

method is applied if other methods are not

applicable or do not meet the goal of satisfying

hazard (risk) assessment. In addition, this

method serves as a redundancy and is used for

the validation of results of “exact” assessment

methods (mentioned above).

Hazard assessment methods always

suffer from major restrictions concerning their

meaningfulness and accuracy. For the interpretation

and validation of results, it is essential to know

the sources of uncertainties and methodical

short-comings. Some of these deficiencies are

summarized below (KIENHOLZ, 2005 [10.]):

• Limited availability of data

• Limited observation (measuring) period

• Lack of “direct” measurements (e.g.

velocity of mass propagation during events;

impact pressure)

• Incomplete or false documentation of past

events

• Inconsistent quality of information and data

due to variable measuring (observation,

monitoring, documentation) standards

• Uncertainties in the selection of relevant

scenarios

• Misjudgement of the effeminacy and

condition (usability) of existing protection

measures

• Misjudgement concerning the “residual risk”

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Overlaying this information makes feasible a

comprehensive assessment of risks for human

health, economic acidities, environment and

cultural heritage.

As shown in this article, the methods

for the assessment of natural hazards still suffer

from major short-comings and significant sources

of inaccuracy. In addition, a comprehensive

understanding of the triggering and displacement

processes of Alpine natural hazards is still

missing due to the limited availability of “direct”

measurements and observation.

Although hazard maps have gained a

key role in the process of preventive planning,

the information provided by these maps should

still be treated with care and only be interpreted

by experts. This reservation especially holds true

for hazard maps devoted to mass movements.

As the standards of hazard mapping in this field

are still under development, preventive planning

concerning rock fall and landslides (unlike flood

and avalanche hazards) is still “in situ nascendi”.

This delay justifies the strong efforts within the

Alpine space to establish and harmonize general

standards for the assessment and mapping of

hazards caused by mass movements.

Anschrift des Verfassers / Author’s address:

DI Dr. Florian Rudolf-Miklau

Bundesministerium für Land- und Forstwirtschaft,

Umwelt und Wasserwirtschaft, Abteilung IV/5,

Wildbach- und Lawinenverbauung

Federal Ministry for Agriculture, Forestry,

Enviroment and Water Management, Department

IV/5, Torrent and Avalanche Control

1030 Wien, Marxergasse 2

Tel.: (+43 1) 71 100 - 7333

FAX: (+43 1) 71 100- 7399

Mail: florian.rudolf-miklau@lebensministerium.at

Homepage: http://www.lebensministerium.at/forst

Literatur / References:

[1.] AULITZKY H. (1992): Die Sprache der "Stummen Zeugen". Tagungsband der Internationalen Konferenz Interpraevent 1992, S. 139-174.

[2.] BERGMEISTER K., SUDA J., HÜBL J., RUDOLF-MIKLAU F. (2009): Schutzbauwerke der Wildbachverbauung. Verlag Ernst und Sohn Berlin (Wiley VCH).

[3.] BOLLSCHWEILER M., STOFFEL M., RUDOLF-MIKLAU F. (2011): Tracking torrential processes on fans and cones. Springer Dortrecht (in preparation).

[4.] BORTER P. (1999): Risikoanalyse bei gravitativen Naturgefahren. Bern: Bundesamt für Umwelt, Wald und Landschaft BUWAL. Umwelt-Materialien 107/I+II.

[5.] BRÜNDL M., ROMANG H., HOLTHAUSEN N., MERZ H., BISCHOF N. (2009):Risikokonzept für Naturgefahren – Leitfaden; Teil A: Allgemeine Darstellung des Risikokonzepts. Bern: Nationale Plattform Naturgefahren PLANAT (vorläufige Fassung).

[6.] BUNDESAMT FÜR UMWELT, WALD UND LANDSCHAFT BUWAL, BUNDESAMT FÜR RAUMPLANUNG BRP, BUNDESAMT FÜR WASSERWIRTSCHAFT BWW (1997): Berücksichtigung von Hochwassergefahren bei der raumwirksamen Tätigkeit, Biel.

[7.] GEBÄUDEVERSICHERUNG GRAUBÜNDEN (2004): Vorschriften für bauliche Maßnahmen an Bauten in der blauen Lawinenzone.

[8.] HÜBL J. (2010):Hochwässer in Wildbacheinzugsgebieten. Wiener Mitteilungen (in press).

[9.] HÜBL J., FUCHS S., AGNER P. (2007): Optimierung der Gefahrenzonenplanung. Weiterentwicklung der Methoden der Gefahrenzonenplanung. IAN-Report 90. Wien: Universität für Bodenkultur (unveröffentlicht).

[10.] KIENHOLZ H. (2005): Gefahrenzonenplanung im Alpenraum – Ansprüche und Grenzen, Imst: Imst: Wildbach- und Lawinenverbau (Zeitschrift für Wildbach-, Erosions- und Steinschlagschutz), Nr. 152, 135-151.

[11.] LOAT R. (2005): Die Gefahrenzonenplanung in der Schweiz. Imst: Wildbach- und Lawinenverbau (Zeitschrift für Wildbach-, Erosions- und Steinschlagschutz), Nr. 152, 77-92.

[12.] MAZZORANA B., FUCHS S., HÜBL J. (2009): Improving risk assessment by defining consistent and reliable system scenarios, Nat. Hazards Earth Syst. Sci., 9: 145–159.

[13.] ONR 24800:2008, Schutzbauwerke der Wildbachverbauung – Begriffe und ihre Definition sowie Klassifizierung. Austrian Standards Institute, Vienna.

[14.] RUDOLF-MIKLAU F. (2009): Naturgefahren-Management in Österreich. Verlag Lexis-Nexis Orac .

[15.] RUDOLF-MIKLAU F., SEREINIG N. (2009): Festlegung des Bemessungshochwassers: Prozessorientierte Harmonisierung für Flüsse und Wildbäche, ÖWAW 7-8: 29 – 32.

[16.] RUDOLF-MIKLAU F., SAUERMOSER S. (Hrsg.) (2011): Technischer Lawinenschutz. Verlag Ernst und Sohn/Wiley Berlin (in preparation).

[17.] SCHROTT L., GLADE T. (2008):Frequenz und Magnitude natürlicher Prozesse; in Flegentreff, Glade (Eds.): Naturrisiken und Sozialkatastrophen. Spektrum Akademischer Verlag Springer: 134 – 150.

[18.] SUDA J., RUDOLF-MIKLAU F., HÜBL J., KANONIER A. (Hrsg.) (2011): Gebäudeschutz vor Naturgefahren. Verlag Spring Wien (in preparation).

[19.] WOLMAN M. G., MILLER J. P. (1960): Magnitude and frequency of forces on geomorphic processes. Journal of Geology 68 (1): 54 – 74.

Key-note papers

event (period of recurrence) for the assessment of

the relevant hazards. (HÜBL ET AL., 2007 [9.])

The elaboration of risk maps is based on the

depiction of objects at risk (risk potentials) within

endangered areas. In principle there are two types

of risk maps available (BORTER ET AL., 1999 [4.]):

•Risk maps only showing risk potential

without assessing (value) them.

• Risk maps based on a graded, qualitative

or quantitative assessment of risks (levels

of risk; e.g. low – medium - high). These

maps are elaborated by combining the

impact intensity with the damage potential

(value), the vulnerability and the exposition

of objects/persons in the endangered area.

Closing remarks

Hazard (risk) assessment and mapping count

among the most important tasks (measures) in

natural hazard management. The maps provide

the key information for most of the other mitigation

measures in order to reduce risk to an acceptable

level. GIS technology provides a powerful tool to

combine spatial information on natural hazards

with other cartographic information concerning

human activities and development actions.

maps provide specific information about the

usability of certain plots for building or other

development purposes. Hazard zone maps are

regularly produced for the hazard types floods,

avalanches and debris flow, and only in few

countries (Switzerland, France, and Italy) for

mass movements as well. In most countries,

hazard zone maps are regulated by legal and

technical standards concerning their content,

formal requirements, approval procedure and

implementation in the development planning.

Some countries have also defined a specific design

Fig. 4: Hazard indication map for mass movements (Bavaria, Germany).

Abb. 4: Gefahrenhinweiskarte für Massenbewegungen (Bayern, Deutschland).

Fig. 5: Hazard map for falls (rock fall) (Switzerland).

Abb. 5: Gefahrenzonenplan Felssturz (Steinschlag) (Schweiz).

Fig. 6: Hazard zone map for torrents (including indication of landslide areas) (Austria).

Abb. 5: Gefahrenzonenplan Wildbäche (einschließlich des Hinweises von Rutschgebieten) (Österreich).

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Zusammenfassung:Die geologische Gefahrenkartierung ist in Europa trotz unterschiedlicher Methoden eine anerkannte Notwendigkeit für die Prävention. Die wissenschaftliche Charakterisierung der Massenbewegungen basiert oft auf ähnlichen Methoden und ist deshalb eher vergleichbar. Hingegen ist die Umsetzung in die Raumplanung und in das Risikomanagement auf eu-ropäischer Ebene sehr unterschiedlich. Der Grund liegt primär in unterschiedlichen Ge-setzen, Verordnungen und Verantwortlichkeiten, bzw. in sozio-ökonomischen Eigenheiten der Länder. Während in Italien und in der Schweiz technische Richtlinien bzw. gesetzli-che Regelungen zur Erstellung von Gefahrenkarten bestehen, gibt es in Österreich nur für Hochwasser bzw. Lawinen Regelungen zur Ausweisung von Gefahrenzonen. In Deutschland wurde eine Empfehlung für die Erstellung von Gefahrenhinweiskarten publiziert. Aufgrund fehlender Regelungen in den alpinen Staaten Europas werden Ereigniskarten, Indexkarten, Gefahrenhinweiskarten und Gefahrenkarten als Grundlagen für die Gefahrenbeurteilung in verschiedenen Maßstäben mit unterschiedlichem Inhalt erarbeitet. Dies und unterschied-liche Definitionen erschweren den Vergleich. Ein multilinguales Glossar, die Einrichtung von Ereigniskatastern bei der Verwaltung und die Festlegung von Mindestanforderungen zur Erstellung von Grundlagen und Gefahrenkarten (Anforderungen hinsichtlich Eingangsdaten und Zweck) sollten daher ein primäres Ziel sein. Im Projekt AdaptAlp (Interreg IV B, Alpine Space) arbeiten die Alpenländer an gemeinsamen Grundsätzen.

countries varies in its quality and quantity: In

some regions, detailed landslide inventories exist

and are the basis for susceptibility and hazard

assessment. Different approaches to hazard

mapping are in practice. This fact and dissimilar

meanings for terms like susceptibility, danger

and hazard make a comparison of the regional

approaches difficult. Using various input data also

handicaps the comparison of hazard assessment.

Within the INTERREG IV B project

“Adaptation to Climate Change in the Alpine

Space “ (acronym AdaptAlp), work package

5.1 Hazard Mapping - Geological Hazards is

focusing on the transnational harmonization of

standards (minimal requirements in the field of

hazard assessment and mapping) by exchanging

experiences in the partner regions. This issue

provides an overview of methods, standards and

procedures without a pretense of completeness.

The definitions of terms used regarding

Introduction

In Alpine regions, slopes of different

morphological and geological conditions are

prone to landslides. Taking into consideration

one of the geological principles for landslide

hazard assessment – the past is the key to the

future – future slope failures will probably occur

in areas with similar geological, morphological

and hydrological situations that have led to past

failures. Some triggering mechanisms happen

sporadically and are not readily obvious. Because

of the lack of memories of past landslide events,

the susceptibility to mass movements is not

considered accurate in land use. But the effects

of mass movements (damages) necessitate new

strategies on how to manage the future potential

of natural (geological) hazards in alpine regions.

Information about landslides in alpine

Mapping of Geological Hazards: Methods, Standards and Procedures (State of Development) - Overview

Geologische Gefahrenkartierung: Methoden, Standards und Verfahren (derzeitiger Status) – ein Überblick

Summary:In spite of different methods used, geological hazard mapping is accepted as a tool for hazard prevention in Europe. Scientific characterization of mass movements is based on similar methods with mostly comparable results. However, the implementation in spatial planning and risk management differs considerably due to different regional legal acts, ordinances, responsibilities and pecularities. Whereas in Italy and Switzerland there are technical guidelines and legal acts regarding landslides and rock fall, in Austria only hazard mapping concerning floods and avalanches is regulated. In Germany a recommendation on how to create a susceptibility map was published. Because of a lack of regulations in European Alpine states’ inventory maps, susceptibility and hazard maps are created in different scales with different contents and quality. This, as well as different defintions of terms such as susceptibility, danger and hazard, makes comparison of hazard assessment products difficult. Consequently a multilingual glossary, landslide inventories at regional authorities and minimal requirements as to how to create hazard maps (requirements concerning input data and purpose of assessment) are necessary. In the AdaptAlp project (Interreg IV B, Alpine Space) the Alpine regions elaborate the common principles.

RICHARD BÄK, HUGO RAETZO, KARL MAYER,

ANDREAS VON POSCHINGER, GERLINDE POSCH-TRÖZMÜLLER

Key-note papers

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give evidence, if e.g. information on the activity,

geometry and slope position of a landslide is

recorded. Recorded geological information

(fourth section) is sometimes specified in detail,

sometimes only the information is given that

geological information is being stored.

In many cases additional information

such as data on vegetation (land cover),

hydrogeological or hydrological conditions, as

well as specific data such as the shadow angle are

stored in the databases.

Most inventories provide information on

the causes or triggers of landslides. In some cases

the damages due to landslides are listed in the

inventory, sometimes even the monetary value of

the damage and the costs of remediation measures.

Most inventory forms also provide information

about how the listed data was gathered (e.g. field

survey), some provide a rating about the reliability

of the degree of precision of the information. In

most databases additional reports, documentation

and bibliography are included or mentioned.

In Austria the Geological survey of

Austria, in cooperation with the Geological Survey

of Carinthia, has created not just one “inventory

map” but a “level of information” (Fig. 1):

Process index maps (map of phenomena

“Prozesshinweiskarte”, “Karte der Phänomene”)

can have different scales (1:50,000 and bigger)

and can be of varying quality; it contains

information about process areas and phenomena

of mass movements that have already happened.

The event inventory (“Ereigniskataster”) records

only those processes for which an event date is

known (5W-questions); it is independent of a

scale. In Carinthia, a digital landslide inventory

was created with historical events of the last

50 years ([7] Bäk et al. 2005). The inventory

map/event map (“Ereigniskarte”) contains only

information about processes for which an event

date is known. The thematic inventory map

contains only information related to a type of

process, categorized according to the quality of

the data.

In Switzerland, the generation of a “map

of phenomena” is mandatory ([30] Raetzo 2002).

As with the Austrian “map of phenomena”, it

shows the geologic-geomorphologic features. An

extensive manual with a digital GIS-legend was

published on a DVD by BWG ([8]BWG 2002,

[14] Kienholz & Krummenacher 1995).

The scale used depends on the purpose

the map is used for, ranging from 1:2,000 (or

even more) for a detailed study to 1:50,000 as

an indicative map ([32] Raetzo & Loup 2009).

On the other hand, the Federal Office for the

Environment (FOEN) manages a database with

all the events where damages were recorded. This

national database is called “StorMe” and contains

data on every natural hazard process: landslides,

debris flows, snow avalanches and floods.

In Italy, a country with a particularly high

landslide risk owing to its landform configuration

and its lithological and structural characteristics,

the need for a complete and homogeneous

overview of the distribution of landslides was

recognized after the disastrous event at Sarno. The

aim of the IFFI Project (Inventario dei Fenomeni

Franosi in Italia – “Italian Landslide Inventory”)

implemented by ISPRA (formerly: APAT, the

Italian Environment Protection and Technical

Services Agency) and by the regions and self-

governing provinces was to identify and map

the landslides in accordance with standardized

and shared methods. The work method included

the collection of historical and archive data,

aerial photo interpretation, field surveys, and

detailed mapping. A “Landslide Data Sheet” was

prepared for collecting the landslide information,

subdivided into three levels of progressively

Key-note papers

phological maps. Using digital DTM data in a GIS

allows the production of hillshades with several

geometries to detect typical landslide forms.

Modern methods for modelling processes are de-

signed for the GIS environment. Slope stability and

rock fall trajectories can be computed over large

areas to get indications of the hazards. Analysis

of aerial photographs is also a classical and

valuable technique to identify landslide features.

More subtle signs of slope movement cannot be

identified on the maps mentioned above. Field

observation by experts is necessary for accurate

assessment. The requirements for acquired data

are raised by the main goal: The accurateness and

detail of input data and scale depends on the aim

of the product – susceptibility map, hazard as-

sessment or risk analyses.

For hazard assessment, information

about possible scenarios is needed. For this

reason it is important that landslide inventories

are induced to sustain landslide knowledge over

time. In most regions of the Alps, inventories have

been established by authorities and are to some

extent available to the public.

Tab.1 gives information about what

kind of data is stored in different landslide event

inventories, and what questions are asked on the

landslide reporting form. For the comparison,

information from the countries Austria (Geological

survey of Austria, of Lower Austria, of Carinthia,

project MASSMOVE, project DIS-ALP), Germany,

Switzerland, Slovenia, Italy, France, Slovakia, Aus-

tralia and the USA (Oregon, Washington, Utah)

was taken into account.

The first section of table 1 shows

if inventories exist. The second section

deals with the basic data, mainly with the

5W-questions: What happened where, when and

why, and who reported it (or made the database

entry). The landslide conditions in the third section

landslides sometimes differ contradictorily in

literature and in practice. For this reason the

second goal of the work package 5.1 named

above is the elaboration of a multilingual glossary.

Landslide inventories

Landslide inventories are the basis for all scientific

and planning activities. They contain the basic

data of natural hazard processes and should

mainly include the facts. Therefore all partner

countries in the AdaptAlp Interreg project are

working on landslide inventories.

[11] Guzzetti 2005 wrote about landslide

inventories: “Despite the ease with which they

are prepared and their immediateness, landslide

inventories are not yet very common. Inventory

maps are available for only a few countries

and mostly for limited areas. This is surprising

because inventory maps provide fundamental

information on the location and size of landslides

that is necessary in the assessment of slope

stability at any scale, and in any physiographical

environment.” Nevertheless, all of the countries

considered for the literature survey have landslide

inventories and maps, even if contents, scales and

the state of completeness vary.

In order to predict landslide hazard

in an area, the morphological, geological, and

hydrological conditions and processes have to be

identified. Their influence on the stability of the

slopes has to be estimated.

Different methods of data acquirement

are used to establish databases to assess hazards:

Landslide inventories as an important tool for the

assessment of the susceptibility of slopes to mass

movements are created nowadays more and more

using digital technology. A general indication of

landslide susceptibility can be obtained based on

landslide inventories, geological, soil and geomor-

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of the geohazards and their causal factors. This

understanding can be used to assess susceptibility.

In the USA the Landslide Inventory

Steering Committee, composed of members of

USGS and State Geological Surveys and other

state agencies, are working on the Landslide

Inventory Pilot Project. The purpose of this project

is to provide a framework and tools for displaying

and analyzing landslide inventory data collected

in a spatially aware digital format from individual

states. To get information about further landslides,

the Oregon Department of Geology and Mineral

Industries, among others, has prepared an

inventory form. Besides information about the

exact location (coordinates) of a landslide, the

following specifications should be listed: date of

slide, activity, estimated dimension (length, width,

depth, volume, estimated dimensions from: aerial

photos, field evaluation), predominant type of

material (rock, debris, earth, fill), predominant

type of movement (fall/topple, flow, translational

slide, rotational slide, spread), approximate

original slope (e.g.: 30° +/- 5°, estimated from

e.g. 1:24K USGS topo map), land use where

slide occurred (forested area, harvested area,

rural area, urban area, agriculture), cause of slide

(road construction, road cut, road fill, earthquake,

preexisting slide, steep natural slope, natural

drainage, human built drainage, other), damage

caused by slide and additional comments.

In California the landslide inventory

maps are available at a scale of 1:24,000.

The inventory was prepared primarily by

geomorphological analysis, interpretation of aerial

photographs and also by field reconnaissance,

interpretation of topographic map contours, and

review of geological and landslide mapping.

Also, each landslide was classified according to

its activity: active or historic, dormant-young,

dormant-mature, dormant-old. The landslide

material (rock, soil, earth, debris) and type of

movement (slide, flow, fall, topple, spread) are

also classified. Furthermore, each landslide is

classified according to a “confidence” (definite,

probable, questionable) assigned by the geological

interpreter. It can be regarded as a measure of

likelihood that the landslide actually exists.

Susceptibility/hazard assessment in Alpine regions

A literature study regarding susceptibility/hazard

mapping ([29] Posch-Trözmüller 2010) shows

the different approaches to hazard assessment in

alpine regions.

For the assessment of natural hazards

(hazard maps) mainly heuristic methods are in

practice. In this case scientific reports, geological

and morphological mapping are the basis for

weighting methods. Statistical analysis (bivariante

or multivariate) are used for the weighting. The

weight of evidence method is based on a statistical

Bayesian bivariate approach. Originally developed

for ore exploration, this probabilistic method is

now commonly used for the statistical assessment

of landslides. It is based on the assumption that

future landslides would be triggered or influenced

by the same or similar controlling factors as

previously registered landslides ([15] Klingseisen

& Leopold 2006, [16] Klingseisen et al. 2006).

In Germany a recommendation on how

to create a susceptibility map is given by the

“Geohazards” team of engineering geologists

of German federal governmental departments

of geology ([37] SGD 2007). Basic minimal

requirements for inventory records are defined,

such as spatial positioning and technical data of

mass movements. Digital modelling (rock fall,

shallow landslides) can be used to identify the

susceptibility of areas to mass movements, verified

by landslide inventories or evaluation through

Key-note papers

that, since the sources for the inventory map of

Slovenia are quite different from each other, the

scales vary but landslides were always mapped at

a quite detailed scale.

In France a database for mass movements

is accessible on the internet. The processes taken

into account are landslides, rock fall, debris flows,

subsidence and bank erosion. For each mass

movement, the following detailed information

can be retrieved: type of movement, detailed

geographical data, information about the quality,

the precision and the origin of the data, detailed

information about the mass movement (size,

activity), the damage caused, the causes for the

movement and geological information as well as

information about the survey of the phenomenon.

A prototype landslide database has

been established by Geoscience Australia in

collaboration with the University of Wollongong

and Mineral Resources Tasmania, displaying the

location of the landslides on a map and providing

information regarding the type of landslide, date

of occurrence (if known), a brief summary of the

event, its cause and damage.

In England after the Aberfan disaster the

UK government funded a number of research

projects to look at the UK’s geohazards ([33]

Reeves 2010). Now in the UK the BGS investigates

geohazards by looking at primary geohazards such

as earthquakes, volcanic eruptions and secondary

geohazards such as landslides, swelling/shrinking

etc. Topics of consideration are the cause of

events, return periods determined by analysis of

past events, affected regions, influence of regional

geology. An inventory is the first step in building an

understanding of the occurrence of geohazards.

Currently BGS maintains two main shallow

geohazard databases: the National Landslide and

the Karst Database. These inventories provide

the basis for analysing the spatial distribution

increasing detail (from: [13] ISPRA, 2008):

• First level: contains the basic information

(location, type of movement, state of

activity) and is mandatory for every

landslide.

• Second level: contains the geometrical,

geological, and lithological parameters,

land use, causes and activation date.

• Third level: provides detailed information

on the damage, investigations and remedial

measures.

A scale of 1:10,000 is used for surveying and

mapping the landslides throughout most of Italy,

only in high mountainous areas or in lower

populated areas is a scale of 1:25,000 used. As

with many regions, the region of South Tyrol

(Autonome Provinz Bozen Südtirol, [27] Nössing

2009) also has a landslide database that resulted

from the IFFI Project. The type of movement, the

litho-logical unit, the volume of the moving masses,

the internal cause and the external trigger, as well

as the induced damage are noted for each event.

The extensive landslide database,

GEORISK of Bavaria, is an essential step to

creating susceptibility maps. Until now 2,800

landslides have been documented in the

database, with information about the type of

movement, the extension, age and status of the

landslides. The following landslide processes are

recorded: flow ("Hangkriechen", "Schuttströme"),

slide ("Rutschungen", "Hanganbrüche"), fall/rock

fall ("Steinschläge", "Felsstürze", "Bergstürze"),

Karst, subsidence ("Erdfälle", "Dolinen", "Senken",

"Schwinden",..). Based on the inventory, maps

were created, showing existing landslides and

their activity (“Karten der Aktivitätsbereiche”).

The Slovenian landslide inventory map

is shown as a small inlet on the susceptibility

map of Slovenia at a scale of 1:250,000. Personal

information from M. Komac (Geo ZS) revealed

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statistics (landslides) and cost analysis (rock falls),

working with a 25x25m grid. The inventory map is

included in the susceptibility map. Also, the local

department of the Austrian Service for Torrent

and Avalanche Control (WLV) creates “hazard

maps” within the “hazard zonation plan”. In

Upper Austria, Lower Austria and Burgenland,

different approaches have been chosen to develop

susceptibility maps (different scales, processes)

derived from existing data sets and maps ([29]

Posch-Trözmüller 2010): The main focus in

Burgenland is concentrated on shallow landslides

with an annual movement rate of 1-2cm. For

the prediction of landslide susceptibility based

on morphological and geological factors, the

method called Weights of Evidence was chosen

([16] Klingseisen et al. 2006). In Lower Austria

susceptibility maps have been created until now

using a heuristic approach based on geological

expertise, historical data and interpretation of DTM

and aerial photos ([36] Schweigl & Hervas 2009).

To provide the municipalities with assistance in

spatial planning, landslide susceptibility maps

were generated for the main settled areas in Upper

Austria (OÖ). The priority, which is a susceptibility

class, was evaluated on the basis of the in-tensity

and the probability of an event for each type of

mass movement ([19] Kolmer 2009). As these

maps include the intensity and the frequency of

mass movements, they can be called “hazard

maps” by definition. Nevertheless it has to be

taken into account that the method of generating

these maps did not include either field work or

remote sensing techniques. The method of assess-

ment is based solely on geological expertise.

The national project of Italy, IFFI, also

represents an important tool for landslide risk

assessment, land use planning and mitigation

measures. By using the information contained in

the database of the IFFI Project and the Corine

Land Cover Project 2000, it was possible to carry

out an initial evaluation of the “level of attention”

on a municipal basis. The level of attention was

for example rated “very high”, when the landslide

points, polygons and lines intersected with urban,

industrial or commercial areas ([13] ISPRA 2008).

The regions in Italy also have programs

in cooperation with the IFFI Project (IFFI started

as a national project and is continued by the

separate regions), as well as with the PAI Project.

For example, the region of Friuli Venezia Giulia

has a landslide inventory that originated within

these two studies, collecting data from several

different regional offices (in particular: Protezione

Civile della Regione and the Direzione Centrale

Risorse Agricole, Naturali, Forestali e Montagna)

as well as from other public subjects that work

on the territory. It homogenizes the information

according to national standards and surveys new

data. The program is used for the evaluation of the

hydrogeological hazard and risk and also to give a

clear and updated view of the interventions made

in the region to preserve vulnerable areas. The

data is recorded in an official GIS structure called

Sitgeo (Geological Service Information System).

The main focus lies on hazard assessment at the

scale of a slope.

Slovenia generated a susceptibility map

of the whole country at a scale of 1:250,000 using

statistical analyses ([20] Komac & Ribicic 2008).

In 2002, BGS (England) developed a nationwide

susceptibility assessment of deterministic

geohazards such as landslides, skrink-swell,

etc. called GeoSure ([33] Reeves 2010). It

was developed from the 50K digital geology

polygons (DiGMap50), published information,

expert judgement knowledge, national landslide

database, national geotechnical information

database and modified DTM. Probabilistic

methods are used for hazard management by

primary geohazards, deterministic methods by

secondary geohazards.

Key-note papers

indicative map is not obligatory in Switzerland,

since the law refers to the standardized hazard

map ([32] Raetzo & Loup 2009). Detailed

information on hazard maps in Switzerland is

given by Raetzo & Loup in this issue [31].

Because of the lack of a regulatory

framework or technical norm concerning

landslides and rock fall in Austria - only the

course of actions concerning floods, avalanches

and debris flows are regulated by law (ordinance

of hazard zone mapping, [34] Rudolf-Miklau &

Schmidt 2004) - the federal states all follow a

different course of action.

At the Geological Survey of Austria,

a database-system for documenting mass

movements in Austria (GEORIOS) containing

information about the different types of

processes, geological, hydrological, geometric

and geographical data, information on studies or

tests carried out as well as mitigation measures

and the source of information (archives, field

work) is in use. Susceptibility maps in different

scales and with different methods (heuristic

approach, neural network analysis) have already

been generated. Using the digital geological

map (1:50,000), the inventory map, map of

phenomena and a lithological map, susceptibility

maps for Carinthia were generated in col-

laboration with the Geological Survey of Austria

(GBA) and the Geological Survey of Carinthia at a

scale of 1:200,000 ([17] Kociu et al., 2006). These

are, of course, still lacking information about

intensity and recurrence period or probability

of occurrence. For a small study area in Styria,

the Geological Survey of Austria generated a

susceptibility map at a scale of 1:50,000 using

neural network analysis ([38] Tilch 2009).

In Vorarlberg risk maps (susceptibility

map, vulnerability map, risk map) were produced

in the course of a university dissertation ([35]

Ruff 2005). For modelling, he used bivariate

field work. Indications of active/inactive landslides

can be found by using registers, mapping and/or

remote sensing (DTM) methods. Potential landslide

areas (where landslides have not yet taken place)

are determined by empirical methods in account

of geological and morphological situation and

land use. Alternatively areas prone to landsliding

can be derived semi-automatically by a cross-over

between DTM and a geological entity. Regarding

rock fall processes, source areas of rock fall are

derived in a first step from landslide inventories

and/or remote sensing (DTM). Usually Alpine

areas with an inclination > 45° are potential rock

fall escarpments. In the second step, the runout

zone is depicted by empiric angle methods

(shadow angle, geometric slope angle) or physical

deterministic methods. The guidelines also include

flow processes, subrosion, subsidence and uplift.

For the whole Bavarian Alps (about

4.300 km²) ([23] Mayer 2007), an “extended

danger map” at a scale of 1:25,000 has already

been presented or is being completed. That

means that, in contrast to the susceptibility map

(without information on intensity and probability),

it includes a qualitative statement about the

probability through a predefined “design event”.

The legend for the rock fall danger map discerns

between “indication of danger”, yes or no, the

legend for the danger map of superficial landslides

discerns 3 entries (source area, accumulation

zone, none), the deep-seated landslides danger

map also discerns 3 entries (indication, indication

in extreme case, none).

The Swiss indicative map (“Gefahren-

hinweiskarte”) is generated at a scale of

1:10,000 to 1:50,000. The legend gives only the

information “indication of hazard” - yes or no,

without specification of classes. It indicates the

potential process areas of rock falls, landslides

and debris flows. It doesn’t include information

about intensity or probability. The creation of an

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Australian method of hazard assessment, which

is quite different from the first ones, as well as

the method applied in the state of Washington

(USA), is also looked into (Tab. 2). Tab. 3 gives

an overview about hazard maps generated in the

considered countries.

Comparison of hazard assessment methods in Switzerland

and Friuli Venezia Giulia (Italy)

The hazard maps in Switzerland are compared

especially to Friuli Venezia Giulia. More detailed

information on the Swiss method is given by

Raetzo & Loup in this issue [31]. The Swiss

method ([30] Raetzo 2002) and the method used

in Italy ([21] Kranitz & Bensi 2009) are based on

an intensity-probability matrix. They differ from

each other in determining the intensity and the

probability of a landslide event.

In Switzerland, 5 degrees of hazard are

used. In Italy the hazard is rated in 4 classes (from

very high [P4] to moderate [P1]).

Concepts of hazard assessment in Switzerland

In Switzerland the method to establish the hazard

map was simplified as much as possible due to

the objective of facilitating its integration into

land use (planning). In order to have simple con-

struction regulations, only 5 degrees of hazard

were defined: high, medium, low, residual and

neglectable hazard. The degree of hazard is

defined in a hazard matrix based on intensity and

probability criteria ([32] Raetzo & Loup 2009).

For the planning of protection measures, more

detailed investigations and calculations are done

(e.g. all energy classes). In general the methods

used are related to the product, scales and the risk

in order to respect economic criteria. Applying

this concept, low efforts were used for the swiss

indicative map (level 1). Important efforts are taken

when a hazard map is established or reviewed

(level 2). Hazard maps are an accurate delineation

of zones on scales from 1:2,000 to 1:10,000.

Detailed analyses and engineering calculations

are foreseen for the planning of countermeasures

or for expertises (level 3). It is planned to apply

this concept of increased efforts for geological

investigations when the assessment takes place

on the second or third level. These investigations

include geologic mapping, geomorphologic

analyses, monitoring, geophysics, numerical

modelling and other methods.

Assessment of the intensity

(Switzerland/ Friuli Venezia Giulia)

Intensities are assessed through a classification

that is represented in table 2.

The assessment of intensities in Switzerland

is different for each process, also for floods

and snow avalanches ([30] Raetzo 2002). For

continuous landslide processes, the only criterion

is the intensity. For spontaneous processes the

intensity and the probability both ranging from

high to low in three classes (high – medium – low)

are needed:

• For rock falls, the intensity is defined by

the energy. High intensity is defined as

e≥300kJ, which is approximately the limit

of resistance of massive armored walls.

• For slides, the mean long-term velocity,

the variation of the velocity (dv, or

acceleration), the differential movement

(D), and the depth of the slide (T) are used

to determine the intensity ([32] Raetzo &

Loup 2009).

• For flowing processes like earth flows, the

potential thickness and the possible depth

of the depo-sition determine the intensity.

Key-note papers

mapping (1:25,000), geomorphological mapping

and analysis (1:5,000), landslide and engineering

data compilation, construction of digital elevation

models (10x10m).

For example, a threshold slope value of

42° was chosen for modelling rock fall source

areas. It does not imply that rock fall will not

occur on lower slopes, but it becomes steadily

less likely with reduced slope angles. A simple

modelling approach was developed for modelling

the rock fall runout area using the direction of

maximum downhill slope defined by an aspect

raster and calculating with a travel angle of 30°.

In southwestern California, soil-slip

susceptibility maps have been produced. These

show the relative susceptibility of hill slopes to

the initiation of rainfall triggered soil slip-debris

flows. They do not attempt to show the extent

of runout of the resultant debris flows. The

susceptibility maps were created in an iterative

process from two kinds of information: locations

of sites of past soil slips and aerial photographs

taken during six rainy seasons that produced

abundant soil slips. These were used as the basis

for a soil slip-debris flow inventory. Also, digital

elevation models (DTM) of the areas were used

to analyze the spatial characteristics of soil slip

locations. Slope and aspect values used in the

susceptibility analysis were 10 metre DTM cells at

a scale of 1:24,000. For convenience, the soil-slip

susceptibility values are assembled on 1:100,000

scale bases ([26] Morton et al. 2003).

Comparison of hazard assessment methods

Methods of hazard assessment used in Switzerland,

Italy (Friuli Venezia Giulia), Australia, France and

USA are considered in this section. First the Swiss

and the Italian methods are compared, as these

define intensity and probability parameters. The

A number of guidelines have been published in

Australia by the Australian Geomechanics Society

concerning mass movements and landslide risk

management, as well as slope management and

maintenance. These guidelines are tools that

were made to be introduced into the legislative

framework of Australian governments at national,

state and local levels, and they are also useful for

land use planning.

Regional susceptibility mapping of

areas prone to landsliding is not yet commonly

undertaken in Australia: Because of a lack of

good inventory maps and validated inventory

databases, landslide hazard mapping is very

limited. Determining temporal probability is often

not possible because of the lack of historical

information ([25] Middleman 2007). Landslide

mapping is generally done on a site-specific scale

and is performed by geotechnical consultants for

the purpose of zoning, building infrastructure

and applying for development approvals ([25]

Middleman 2007). Mineral Resources Tasmania

(MRT, Department of Infrastructure, Energy and

Resources, State Government of Tasmania) is

the only state government agency in Australia

to undertake several activities with respect

to landslides, including regional mapping,

administration of declared landslide areas and

monitoring of a small number of problematic

landslides. Mazengarb ([24], 2005) describes in

detail the methodology of creating the “Tasmanian

landslide hazard map series” that started with a

pilot area coinciding with the Hobart municipality.

The following basic information was used to

create the individual landslide hazard maps

(note: In the report the maps are called “hazard

maps”, but on the homepage, where the maps are

accessible via the internet, the individual maps

are called “susceptibility maps”, but, nonetheless,

giving “hazard zones” in the legends.): geological

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for the statistical evaluation of the return period,

the values will be assigned by a typological

approach based on bibliographical data inherent

to the characteristics of temporal return of the

various typologies of landslides. This will be

calibrated on geomorphologic observations,

analyses of historical photos, and aerial pictures

(which is also the case in the Swiss method) from

the year 1954 up to now, and historical data from

local sources. The probability is then classified in

4 classes:

• high: 1-30 years (active landslides,

continuous and/or intermittent landslides,

quiescent – episodic with high frequency)

• medium: 30-100 years (quiescent – episodic

landslides with medium frequency)

• low: 100-300 years (quiescent – episodic

landslides with low frequency)

• >300 years (ancient landslides or

palaeolandslides).

Other approaches to hazard assessment

France

Malet et al. ([22] 2007) describes the French

methodology for landslide risk zoning (Plan

de Prévention des Risques), where 3 classes of

risk (R1, R2, R3) with specific rules for land use

regulations and urbanism can be represented

in a matrix depicting hazards and potential

consequences. This qualitative method is based

on the expert opinion of the scientist. No

specific investigation is necessary, available data

and reports are sufficient. The scale of work is

specified as 1:10,000. The hazard map is an

interpretation of the type of processes, activity,

age and magnitude of the processes; the hazard

map is an interpretation of the type of processes,

activity, magnitude and frequency. The risk map is

the crossing of the hazard map and the inventory

map of major stakes ([22] Malet et al. 2007).

Australia

In the Australian guidelines for landslide

susceptibility, hazard and risk zoning for land

use planning, the number of events per length

of source area per year (rock fall) or per square

kilometer of source area per year (slides) is used

for describing the hazard of small landslides. For

large landslides, the annual probability of active

sliding or the annual probability that movement

will exceed a defined distance or the annual

probability that cracking within a slide exceeds

a defined length is used to describe the hazard.

The description of the hazard should include the

classification and the volume or the area of the

landslides.

Whether landslide intensity is required

for hazard zoning is to be determined on a case-

by-case basis. For rock fall hazard zoning, it is

likely to be required. Therefore the frequency

assessment is much more important for hazard

zonation than the intensity according to AGS.

Intensity assessment in Australia:

The landslide intensity is assessed as a spatial

distribution of:

• the velocity of sliding coupled with slide

volume or

• the kinetic energy (e.g. rock falls, rock

avalanches), or

• the total displacement or

• the differential displacement or

• the peak discharge per unit width (m3/m/

sec., e.g. debris flows)

For basic and intermediate level assessments of

intensity, only the velocity and volume might be

assessed. But for the advanced assessments of

rock fall or debris flow hazard, the energy should

be determined. In AGS ([3] 2007b) it is noted that

“there is no unique definition for intensity. Those

carrying out the zoning will have to decide which

definition is most appropriate for the study”.

Assessment of the probability

(Switzerland/ Friuli Venezia Giulia)

Swiss method ([32] Raetzo & Loup 2009):

The probability assessment of the Swiss method

defines the probability in analogy to the recur-

rence periods used in flood and avalanche

protection (30, 100, 300 years return period),

which corresponds to yearly probabilities of 0.03,

0.01 and 0.003. An event with a return period

higher than 300 years is normally also considered

for the assessment (risk analysis, residual risk,…).

It corresponds mainly to the flood prevention

strategy.

The probability of an event has to be calculated

or estimated:

• Big events (“Bergsturz”, >1mio m3) do not

recur. For smaller events the probability is

defined by the elements at risk.

• For continuous slides the probability is 1 (or

100%), meaning that the event is happening

already. Scenarios are defined when sudden

landslide failure or acceleration can take

place. When fast moving landslides (debris

or earth slides according to Varnes) have

long run-out distances, the process is

moving into a flow. In this case the Swiss

method takes into account the change from

the first to the second move and criteria of

the flow processes are applied (see below).

• The probability for debris and earth flows is

determined through field work and based

on inventory data. Numerical modelling

of flow processes is also used and the

importance of these results is rising.

Method of Friuli Venezia Giulia ([21] Kranitz &

Bensi 2009):

The possible frequency or occurrence probability

is determined through the records of historical

events. If there is a lack of sufficient historical data

For landslides and rock falls the Swiss evaluation

is normally based on intensity maps where 3 or

more classes can be chosen. (e.g. 10-20,000 kJ

for rock falls).

In Italy, different methods of assessment

are used. For example, the regional method

of Friuli Venezia Giulia ([21] Kranitz & Bensi

2009) for rock fall: The intensities are classified

by different methods using several tables. For fall

processes, a table with definition of classes of the

geometry is determined (after [12] Heinimann et

al. 1998). The classification takes into account the

block size of the rocks ([21] Kranitz & Bensi 2009).

Another table determines the velocity factor (v),

also ranging from 1- 3, using the definitions from

Cruden & Varnes ([9], 1996). The intensity class,

ranging from 1- 9, is then determined with the

geometry-velocity matrix.

Comparison between the Swiss and the Italian

intensity classification:

The differences in determining the intensity

between the Swiss ([32] Raetzo & Loup 2009)

and the Friuli method ([21] Kranitz & Bensi

2009) are:

• For fall processes in the Italian method,

the energy does not need to be calculated,

only the block sizes and the velocity need

to be determined, while in Switzerland the

energy is calculated.

• The Italian method does not differentiate

for continuous processes. Switzerland

uses the mean long-term velocity for these

continuous landslides.

• The Swiss method determines 3 intensity

classes to apply within the hazard matrix

for the land use planning. If protection

measures are planned in Switzerland, all

the energy values are taken into account.

The Italian method determines 9 intensity

classes.

Key-note papers

Seite

36

Seite

37

is regulated by a decree (“Verordnung des

Bundesministeriums für Land- und Forstwirtschaft,

1976“, BGBl. Nr. 436/1976). The scale usually

ranges between 1:2,000 and 1:5,000, it must not be

smaller than 1:50,000. The map gives information

about the determined effects in the relevant area

of catchment areas (torrent buffer areas) in red

and yellow hazard zones. The design event is

determined by a return period of 150 years.

In the red hazard zone, infrastructures

cannot be maintained or can only be maintained

with a very high effort due to the high intensity

or a high recurrence of avalanches or torrential

events.

The yellow hazard zone includes all

other areas affected by avalanches and torrents.

The constant use of these areas by infrastructures

is affected due to these hazards. The hazard

zone map also delineates blue areas (for the

implementation of technical or forestal measures

as well as protective measures), as well as brown

and violet reference areas.

The brown reference areas are areas

presumably affected by other hazards than

torrents or avalanches, like rock fall or landslides.

The violet reference areas are areas, where soil

and terrain have to be protected in order to keep

up their protective function.

In Switzerland, the Federal Office for

the Environment FOEN (Bundesamt für Umwelt,

BAFU) is responsible for creating guidelines

concerning protection against natural hazards

(floods, mass movements, snow avalanches). The

concepts are similar for these processes to reach

a certain level of protection. Protection against

natural hazards takes place on the principle of

integral risk management, taking into account:

• Prevention of an event

• Conflict management during an event

• Regeneration and reconstruction after

an event.

The Swiss regulations are described in more detail

by Raetzo in this issue [31].

In some regions of Italy the hazard is

assessed using the Swiss method ([30] Raetzo

2002). This method is similar to the method planned

by the Italian legislative body for hydrogeological

risk assessment. Appropriate changes have been

introduced in order to standardize these aspects

and contextualize the method for territorial

jurisdiction ([21] Kranitz & Bensi 2009). Four

classes of hazards are distinguished, ranging

from very high (P4 “molto elevata”), high (P3

“elevata”), medium (P2 “media”), to moderate (P1

“moderata”).

The French hazard map, PPR, Plan

de prevention des risques, is made by the local

authorities (mayors), but with support by national

agencies like CEMAGREF or agencies of the

departments. It was introduced in 1995. Made

by the municipalities at a scale of 1:10,000

-1:25,000, the plans need to be authorized

by the prefects in collaboration with the local

authorities and the civil society, such as insurance

companies. The PPR gives information about the

identification of danger zones; 3 classes of risk

with specific rules for land use regulations and

urbanism can be represented. The method is a

qualitative method based on the expert judgment

of the scientist. There are PPRs for floods, mass

movements, avalanches and wood fires. Non-

observance of the PPR has legal consequences.

In Spain the Geological Institute of

Catalonia (IGC) is responsible to “study and

assess geological hazards, including avalanches,

to propose measures to develop hazard forecast,

prevention and mitigation and to give support

to other agencies competent in land and urban

planning, and in emergency management” ([28]

Oller et al. 2010). Therefore, the IGC is charged

with making official hazard maps with such

finality. These maps comply with the Catalan

Key-note papers

of this uncertainty, it has been common practice

to report the likelihood of landsliding using

qualitative terms such as “likely”, “possible” or

“unlikely”.”

Procedures of hazard mapping

in the considered regions

Tab. 3 gives an overview of hazard maps generated

in the considered countries.

In Germany a recommendation on how to create

a susceptibility map is given by the “Geohazards”

team of engineering geologists of German federal

governmental departments of geology ([37] SGD

2007). In 2007, the LfU completed the Landslide

susceptibility map of Oberallgäu (Bavaria). For

this map, the processes of rock falls, superficial

landslides and deep seated landslides were

treated separately. The susceptibility maps for rock

falls and superficial landslides were created using

modelling, whereas the susceptibility map for

deep seated landslides was created empirically,

assuming that deep seated landslides tend to occur

in areas already affected by landslides in the past,

but taking into consideration that process areas

can expand during reactivation of a landslide. The

basic data used for the investigations contained

the following: topographic map 1:25,000, raster

format; geological map 1:25,000 or 1:50,000 and

also maps in smaller scales where the detailed

maps were not available, vector format; DTM,

10m raster data; aerial photographs 1:18,000 and

orthophotos; data on forests; GEORISK data (BIS-

BY); data on catchment areas; historical data.

In Austria only the Austrian Service for

Torrent and Avalanche Control (WLV) generates

hazard maps, called “Gefahrenzonenkarte” or

“hazard zone maps” for floods, avalanches and

debris flows within the “Hazard zonation plan”

(“Gefahrenzonenplan”). This is regulated by law

(Forest Act BGBL. 440/1975). The implementation

Frequency assessment in Australia:

In AGS ([3], 2007b), the assessment of the

frequency of a landslide event for the generation

of hazard maps is usually determined from the

assessment of the recurrence intervals (the average

time between events of the same magnitude) of

the landslides. If the variation of recurrence inter-

val is plotted against magnitude of the event, a

magnitude-frequency curve is obtained.

The methods listed for determining the

frequency include: historical records; sequences

of aerial photographs and/or satellite images;

silent witnesses; correlation with landslide

triggering events (rain storms, earthquakes); proxy

data (e.g. pollen deposition, lichen colonization,

fauna assemblages in ponds generated by a

landslide,…); geomorphologic features (ground

cracks, fresh scarps,…); subjective assessment.

It is further noted that “landslides of

different types and sizes do not normally have

the same frequency (annual probability) of

occurrence. Small landslide events often occur

more frequently than large ones. Different

landslide types and mechanics of sliding have

different triggers (e.g. rainfalls of different

intensity, duration and antecedent conditions;

earthquakes of different magnitude and peak

ground acceleration) with different recurrence

periods. Because of this, to quantify hazard, an

appropriate magnitude-frequency relationship

should in principle be established for every

landslide type in the study area. In practice, the

data available is often limited and this can only be

done approximately.” A row of useful references

on frequency assessment are listed in AGS ([3],

2007b).

In AGS ([1], 2000) it is noted that “even

if extensive investigation is carried out, assessing

the probability of landsliding (particularly for an

unfailed natural slope) is difficult and involves

much uncertainty and judgement. In recognition

Seite

38

Seite

39

rainfall-triggered soil-slip debris flows ([26] Mor-

ton et al., 2003).

The state of Utah prepared a landslide

susceptibility map for the whole state at a scale

of 1:500,000 for deep seated landslides, based

on existing landslides and slope angle thresholds

for different geologic units. The susceptibility is

delineated in 4 classes: high – moderate – low –

very low ([10] Giraud & Shaw, 2007).

Conclusion and recommendations

Guzzetti ([11], 2005) discusses hazard assessment

in his thesis: “Despite the time [since the defini-

tion of “landslide hazard” given by Varnes and the

IAEG Commission on Landslides and other Mass

Movements ([39], 1984)] and the extensive list

of published papers – most of which, in spite of

the title or the intention of the authors, deal with

landslide susceptibility and not with landslide

hazard”, landslide hazard assessment at the basin

scale is sparse. And further: “This is largely due

to difficulties associated with the quantitative

determination of landslide hazard.” In carrying out

the literature survey, this unfortunately proved to

be true and contributed to the confusion existing

with definitions ([29] Posch-Trözmüller 2010).

The differences call first for a national

harmonization and second for international

comparable methods (minimal requirements).

To assess landslide hazards, the

geological, morphological, hydrogeological and

hydrological conditions must be known and

analysed: The differences regarding acquisition of

information and assessment of the susceptibility/

hazard of slopes to landslides and rock fall shown

in the chapter above call for a “harmonization”

of the different methods (e.g. parameters,

minimal requirements). Hazard assessment

needs information about possible scenarios.

Landslide inventories sustain landslide knowledge

through time and represent the main resource for

susceptibility/hazard assessment. The evidence

identified in the field are the facts dealing with

natural hazards. Inventories are the essential base

for accurate hazard/risk assessment and have

therefore to be established by authorities.

The variability of phenomena of mass

movements makes regulations concerning

methods of hazard assessment difficult. Guidelines

regarding hazard assessment should declare the

minimal requirements taking into account the

final objective and the scale of product.

Key-note papers

hazard zonation maps at a scale of 1:12,000.

The hazard assessment included evaluating a

“landslide frequency rate (LFR)“ and a “landslide

area rate for delivery (LAR)”. The LFR is obtained

by taking the number of delivering landslides

per landform, divided by the total area of that

landform, and normalized to the period of study.

The LAR is the area of delivering landslides

normalized to the period of study and the area of

each landform. The resulting values are multiplied

by one million for easier interpretation.

In California soil-slip susceptibility maps

were produced at a scale of 1:24,000 delineating

the susceptibility in 3 classes: low, moderate and

high. They give information about the relative sus-

ceptibility of hill slopes to the initiation sites of

Urban Law (1/2005), which indicates that in those

places where a risk exists, building is not allowed.

For hazard mapping, the work is done on two

scales: land planning scale (1:25,000), and urban

scale (1:5,000 or more detailed). These scales

imply different approaches and methods to obtain

hazard parameters. The maps are generated in

the framework of a mapping plan or as the final

product of a specific hazard report.

The Australian AGS guidelines ([1] AGS,

2000, [2]- [6] AGS 2007a-e) provide for a hazard

zonation at a local (1:5,000 -1:25,000) and a site

specific (>1:5,000, typically 1:5,000 -1:1,000)

scale with 5 hazard descriptors: very high – high

– moderate – low – very low.

The state of Washington (USA) generated

Fig. 1: Workflow of hazard mapping. ([18] Kociu et al. 2010)

Abb. 1: Flussdiagramm zum Prozess Gefahrenkartierung. ([18] Kociu et al. 2010)

Prozesshinweiskarte(Karte der Phänomene)

Ereigniskataster

Ereigniskarte

Gefahrenpotentialkarte(Karte der potentiellen Wirkungsbereiche)

Gefahrenhinweiskarte

Gefahrenkarte

Risikokarte

Inte

rpre

tatio

nseb

ene

/ Bew

ertu

ngse

bene

Grunddispositionskarte

Thematische Inventarkarte

Standortparameterund -verhältnisse

Erweiterte Dispositionskarte

quan

titat

ivqu

alita

tiv /

sem

iqua

ntita

tiv

Info

rmat

ions

eben

e

Dispostionskarte

Seite

40

Seite

41

Key-note papers

Tab.

1: C

ompa

rison

of i

nfor

mat

ion

colle

cted

for d

iffer

ent i

nven

torie

s

Tab.

1: V

ergl

eich

der

Info

rmat

ione

n in

Ere

igni

skat

aste

rn

Cou

ntri

es

Aus

tria

DC

HSL

OIT

FA

US

USA

GBA

NÖ

KM

MS

By

CH

SLO

ITF

AU

SO

WU

Inve

ntor

yx

xx

xx

xx

xx

xx

xx

x

Bas

ic in

form

atio

nw

here

xx

xx

xx

xx

xx

xx

xx

whe

nx

xx

xx

xx

xx

xx

xx

x

wha

tx

xx

xx

xx

xx

xx

xx

x

why

xx

xx

x

x

xx

xx

who

xx

xx

x

x

xx

xx

xx

repo

rted

whe

nx

x

x

xx

x

x

x

Land

slid

e co

nditi

ons

activ

ity

xx

x

x

xx

xx

x

geom

etry

x

xx

xx

xx

xx

xx

xx

slop

e po

sitio

nx

x

x

xx

x

appr

ox. o

rigi

nal s

lope

x

x

x

site

des

crip

tion

x

xx

x

dept

h to

bed

rock

x

x

dept

h to

fai

lure

pl

ane

x

slop

e as

pect

xx

xx

x

x

slop

ex

x

x

Geo

logy

in g

ener

al

xx

xx

x

x

xx

x

Geo

logy

, spe

cifie

dge

olog

ic/ t

ecto

nic

unit

xx

x

x

xx

x

lit

holo

gy/ s

trat

igra

phy

xx

x

x

xx

x

be

ddin

g at

titud

ex

x

x

x

w

eath

erin

gx

x

x

ge

otec

hnic

al

prop

ertie

sx

xx

xx

x

x

x

ge

otec

hnic

alpa

ram

eter

s x

x

x

ro

ck m

ass

stru

ctur

ex

x

x

jo

ints

/ joi

nt s

paci

ngx

x

x

x

di

scon

tinui

ties

x

x

x

st

ruct

ural

co

ntri

butio

ns

xx

x

Land

cov

er/ u

se

x

x

x

x

x

Hyd

roge

olog

y

xx

x

x

Rel

atio

nshi

p to

rai

nfal

l

x

x

x

Cla

ssifi

catio

n of

mas

s m

ovem

ents

x

x

x

Cla

ssifi

catio

nty

pex

xx

xx

xx

x

x

xx

x

ra

te o

f mov

emen

tx

x

x

m

ater

ial

x

x

x

x

w

ater

con

tent

x

x

x

Cau

ses,

Tri

gger

x

xx

xx

xx

x

x

x

Prec

urso

ry s

igns

x

Sile

nt w

itnes

ses

x

Dam

age

x

x

xx

xx

xx

xx

x

"Haz

ard"

to in

fras

truc

ture

x

x

x

x

Rem

edia

l mea

sure

s

xx

xx

x

Cos

ts o

f mea

sure

s an

d in

vest

igat

ion

x

x

x

Met

hods

use

d

x

x

xx

x

xx

xx

Deg

ree

of p

reci

sion

in

fo/ r

elia

bilit

y

x

x

x

x

Rep

orts

etc

.

xx

xx

xx

x

x

Seite

42

Seite

43

Key-note papers

Tab.

2: C

ompa

rison

of t

he in

tens

ity-a

sses

smen

t in

Switz

erla

nd, I

taly

and

Aus

tralia

Tab.

2: V

ergl

eich

Inte

nsitä

t – G

efah

rena

bsch

ätzu

ng in

der

Sch

wei

z, in

Ital

ien

und

in A

ustra

lien

Swit

zerl

and

low

inte

nsit

ym

oder

ate

inte

nsit

yhi

gh in

tens

ity

rock

fall

E<30

kJ30

kJ<

E<30

0kJ

E>30

0kJ

E=en

ergy

cont

inou

s sl

ides

v≤2c

m/y

ear

dv, D

, T

2cm

/yea

r<v<

10cm

/yea

r

dv, D

, T

v>10

cm/y

ear,

(or

1m d

islo

catio

n pe

r ev

ent)

dv, D

, T

v=ve

loci

tydv

=va

riat

ion

of v

, ac

cele

ratio

nD

=di

ffere

ntia

l m

ovem

ent

T=th

ickn

ess

spon

tane

ous

slid

es

M<

0.5m

0.5m

<M

<2m

; h<

1mM

>2m

; h>

1mM

=th

ickn

ess

of

pote

ntia

lly d

ispl

aced

m

ass

flow

(ear

th fl

ow)

M<

0.5m

0.5m

<M

<2m

; h<

1mM

>2m

; h>

1mh=

thic

knes

s of

ac

cum

ulat

ion

of

shal

low

slid

e or

flow

cree

p (+

Perm

afro

st)

v≤2c

m/y

ear

dv, D

, T

2cm

/yea

r<v<

10cm

/yea

r

dv, D

, T

v>10

cm/y

ear,

disl

ocat

ion

per

even

t >1m

dv, D

, T

subs

iden

cedo

lines

pot

entia

lly e

xist

ing

or

solu

ble

rock

s (g

ypsu

m, e

tc.)

pres

ence

of d

olin

es v

erifi

eddo

lines

and

dan

ger

of

colla

psin

g R

aetz

o &

Lou

p ([

32],

200

9)

Ital

y in

tens

ity 1

inte

nsity

2in

tens

ity 3

inte

nsity

4in

tens

ity 6

inte

nsity

9

rock

fall

SG=

1 an

d v=

1 (m

eani

ng:

bloc

k di

am.<

0.5m

ex

trem

ely

slow

, <16

mm

/ye

ar) o

r v=

2 (m

eani

ng: v

ery

slow

(16m

m/

year

to r

apid

[1

.8m

/hou

r])

SG=

2 (m

eani

ng:

bloc

k di

amet

er

0.5-

2m),

v=1

(mea

ning

ex

trem

ely

slow

, <16

mm

/ye

ar),

or:

SG=

1 (<

0.5m

) an

d v=

2 (1

6mm

/yea

r to

1,

8m/h

our)

SG=

3 (d

>2m

), v=

1 (<

16m

m/

year

) or:

SG

=1

(<0.

5m),

v=3

(ver

y hi

gh

to e

xtre

mel

y ra

pid:

3m

/min

to

5m

/sec

.)

SG=

2 (d

=0.

5-2m

), v=

2 (1

6mm

/yea

r to

1,

8m/h

our)

SG=

2 (d

=0.

5-2m

), v=

3 (3

m/

min

. to

5m/

sec.

)

SG=

3 (d

>2m

), v=

3 (3

m/m

in.

to 5

m/s

ec.)

SG=

geom

etry

fact

or,

v=ve

loci

ty fa

ctor

slid

e

SG=

1 (<

0.5m

), v=

1 (1

6mm

/ye

ar to

1.8

m/

hour

)

SG=

2 (d

epth

: 2-

15m

), v=

1 (<

16m

m/y

ear)

, or

: SG

=1

(<2m

), v=

2 (1

6mm

/yea

r to

1,

8m/h

our)

SG=

3 (d

epth

>15

m),

v=1

(<16

mm

/ye

ar) o

r: S

G=

1 (d

epth

<2m

), v=

3 (v

ery

high

to

ext

rem

ely

rapi

d: 3

m/m

in

to 5

m/s

ec.)

SG=

2 (d

epth

: 2-

15m

), v=

2 (1

6mm

/yea

r to

1,

8m/h

our)

SG=

2 (d

epth

: 2-

15m

), v=

3 (3

m/m

in. t

o 5m

/sec

.)

SG=

3 (d

epth

>15

m),

v=3

(3m

/min

. to

5m

/sec

.)

Kra

nitz

& B

ensi

([21

], 2

009)

Aus

tral

iaW

heth

er la

ndsl

ide

inte

nsity

is r

equi

red

for

haza

rd z

onin

g is

to b

e de

term

ined

on

a ca

se-b

y-ca

se

basi

s. F

or r

ock

fall

haza

rd z

onin

g it

is li

kely

to b

e re

quir

ed. T

he la

ndsl

ide

inte

nsity

is a

sses

sed

as a

sp

atia

l dis

trib

utio

n of

:

rock

fall,

roc

k av

alan

che

The

kine

tic e

nerg

y or

or

the

tota

l dis

plac

emen

t or

the

diffe

rent

ial d

ispl

acem

ent,

or

slid

eTh

e ve

loci

ty o

f slid

ing

coup

led

with

slid

e vo

lum

e or

the

tota

l dis

plac

emen

t or

the

diffe

rent

ial

disp

lace

men

t, or

flow

The

peak

dis

char

ge p

er u

nit w

idth

(m3/

m/s

ec.,

e.g.

deb

ris

flow

s)

For

basi

c an

d in

term

edia

te le

vel a

sses

smen

ts o

f int

ensi

ty o

nly

the

velo

city

and

vol

ume

mig

ht b

e as

sess

ed, b

ut fo

r ad

vanc

ed a

sses

smen

ts o

f roc

k fa

ll or

deb

ris

flow

haz

ard

the

ener

gy s

houl

d be

as

sess

ed.

sour

ce: A

GS

([2]

, 200

7a)

Seite

44

Seite

45

Key-note papers

Anschrift der Verfasser / Authors’ addresses:

Richard Bäk

Amt der Kärntner Landesregierung

Abt. 15 Umwelt

Unterabteilung Geologie und Bodenschutz

Flatschacher Straße 70, A – 9020 Klagenfurt

Karl Mayer

Bayerisches Landesamt für Umwelt

Abt. 6 Wasserbau, Hochwasserschutz,

Gewässerschutz

Ref. 61 Hochwasserschutz und alpine

Naturgefahren

Lazarettstraße 67

D – 80636 München

Gerlinde Posch-Trözmüller

Geologische Bundesanstalt

Fachabteilung Rohstoffgeologie

Neulinggasse 38, A-1030 Wien

Andreas von Poschinger

Bayerisches Landesamt für Umwelt

Abt. 10 Geologischer Dienst

Ref.106 Ingenieurgeologie, Georisiken,

Lazarettstraße 67, D – 80636 München

Hugo Raetzo

Federal Office for the Environment FOEN

Bundesamt für Umwelt BAFU

CH - 3003 Bern, Schweiz

Literatur / References:

[1] AGS - AUSTRALIAN GEOMECHANICS SOCIETY, SUB-COMMITTEE ON LANDSLIDE RISK MANAGEMENT (2000): Landslide Risk Management Concepts and Guidelines. Australian Geomechanics, Vol 35, No 1, March 2000.

[2] AGS (2007a). Guideline for Landslide Susceptibility, Hazard and Risk Zoning for Land Use Planning. Australian Geomechanics Society. Australian Geomechanics, Vol 42, No 1, March 2007.

[3] AGS (2007b). Commentary on Guideline for Landslide Susceptibility, Hazard and Risk Zoning for Land Use Planning. Australian Geomechanics Society. Australian Geomechanics, Vol 42, No 1, March 2007.

[4] AGS (2007c). Practice Note Guidelines for Landslide Risk Management. Australian Geomechanics Society. Australian Geomechanics, Vol 42, No 1, March 2007.

[5] AGS (2007d). Commentary on Practice Note Guidelines for Landslide Risk Management 2007. Australian Geomechanics Society. Australian Geomechanics, Vol 42, No 1, March 2007.

[6] AGS (2007e). The Australian GeoGuides for slope management and maintenance. Australian Geomechanics Society. Australian Geomechanics, Vol 42, No 1, March 2007.

[7] BÄK, EBERHART, GOLDSCHMIDT, KOCIU, LETOUZE-ZEZULA & LIPIARSKI: Ereigniskataster und Karte der Phänomene als Werkzeug zur Darstellung geogener Naturgefahren (Massenbewegungen), Arb. Tagg. Geol. B.-A., Gmünd 2005.

[8] BWG - BUNDESAMT FÜR WASSER UND GEOLOGIE: Naturgefahren, Symbolbaukasten zur Kartierung der Phänomene, 2002

[9] CRUDEN D.M. UND VARNES D.J.: Landslide types and processes. In: A. Keith Turner & Robert L. Schuster (eds): Landslide investigation and mitigation: 36-75. Transportation Research Board, special report 247. Washington: National Academy Press, 1996.

[10] GIRAUD, R.E., SHAW, L.M.: Landslide Susceptibility Map of Utah. MAP 228DM, Utah Geological Survey, Utah Department of Natural Resources, Salt Lake City 2007.

[11] GUZZETTI, F.: Landslide hazard and risk assessment. Diss. Math.-Naturwiss. Fak. Univ. Bonn, Bonn 2005.

[12] HEINIMANN, H.R., VISSER, R.J.M., STAMPFER, K.: Harvester-cable yarder system evaluation on slopes: A Central European study in thinning operations. In: Schiess, P. and Krogstad, F. (Eds.): COFE Proceedings “Harvesting logistic: from woods to markets”, 41-46. Portland, OR, 20-23 July, 1998.

[13] ISPRA INSTITUTE FOR ENVIRONMENTAL PROTECTION AND RESEARCH: Landslides in Italy. Special report 2008. 83/2008, Rome 2008.

[14] KIENHOLZ, H., KRUMMENACHER, B.:Empfehlungen Symbolbaukasten zur Kartierung der Phänomene Ausgabe 1995, Mitteilungen des Bundesamtes für Wasser und Geologie Nr. 6, 41 S., Reihe Vollzug Umwelt VU-7502-D, Bern 1995.

Com

pari

son

of

haza

rd m

aps

Cou

ntri

es/ p

roje

cts

Aus

tria

: W

LVSw

itze

rlan

d:

FOEN

/BA

FUIt

aly:

Friu

li, V

enet

oIt

aly:

G

uzze

tti

Fran

ce:

PPR

Aus

tral

ia:

AG

SU

SA:

Was

hing

ton

Scal

e1:

2,00

0-1:

5,00

01:

2,00

0- 1

:10,

000

deta

ilna

tiona

l is

poss

ible

, re

gion

al

1:10

,000

(u

rban

), -1

:25,

000

(rur

al)

1:5,

000-

1:25

,000

1:

12,0

00

Bas

ic d

ata:

su

scep

tibili

ty m

apev

entu

ally

x

x

Bas

ic d

ata:

inve

ntor

yx

xx

xx

xx

Ret

urn

peri

ods

cons

ider

ed fo

r la

nd

use

(pro

babi

lity)

150

year

s

30 y

ears

100

year

s30

0 ye

ars

(Res

idua

l ris

k zo

nes

for

RP>

300y

)

30 y

ears

100

year

s30

0 ye

ars

>30

0 ye

ars

Met

hod

(ass

essm

ent,

mod

ellin

g)

quan

titat

ive,

st

atis

tic,

empi

rica

l

quan

titat

ive,

st

atis

tic, q

ualit

ativ

e (in

cl. fi

eld

inve

stig

atio

n)

quan

titat

ive,

st

atis

tical

(in

cl. fi

eld

inve

stig

atio

n)

empi

rica

l, pr

obab

ilist

icqu

alita

tive

stat

istic

and

em

piri

cal

stat

istic

al

Lege

nd:

Leve

ls o

f haz

ard

2 (fo

r to

rren

t an

d de

bris

flo

w),

indi

catio

n fo

r la

ndsl

ides

and

ro

ck fa

ll

54

52

(3)

53

Tab.

3: C

ompa

rison

of d

iffer

ent h

azar

d m

aps,

thei

r sca

les

and

lege

nds

(leve

ls o

f haz

ard)

Tab.

3: V

ergl

eich

von

ver

schi

eden

en G

efah

renk

arte

n, M

aßst

äben

und

Leg

ende

n (G

rad

der G

efah

ren)

Seite

46

Seite

47

[15] KLINGSEISEN, B., LEOPOLD, PH.: Landslide Hazard Mapping in Austria.-GIM International 20 (12): 41-43, 2006.

[16] KLINGSEISEN, B., LEOPOLD, PH., TSCHACH, M.: Mapping Landslide Hazards in Austria: GIS Aids Regional Planning in Non-Alpine Regions. ArcNews 28 (3): 16, 2006.

[17] KOCIU, A., LETOUZE-ZEZULA, G., TILCH, N., GRÖSEL, K.: Georisiko-Potenzial Kärnten; Entwicklung einer GIS-basierten Gefahrenhinweiskarte betreffend Massenbewegungen auf Grundlage einer digitalen geologischen Karte (1:50,000) und eines georeferenzierten Ereigniskatasters. Endbericht, Gefährdungskarte, Ausweisung von Bereichen unterschiedlicher Suszeptibilität für verschiedene Typengruppen der Massenbewegung. Bund/Bundesländerkooperation KC-29, Bibl. Geol. B.-A., Wiss. Archiv, Wien, 2006

[18] KOCIU, A., TILCH N., SCHWARZ L,. HABERLER A., MELZNER S.: GEORIOS - Jahresbericht 2009; Geol.B.-A. Wien 2010.

[19] KOLMER, CH.: Geogenes Baugrundrisiko Öberösterreich. Vortrag im Rahmen des Landesgeologentages 2009, 26.2.2009, St. Pölten, 2009.

[20] KOMAC, M.; RIBICIC, M.: Landslide Susceptibility Map of Slovenia 1:250,000. Geological Survey of Slovenia, Ljubljana 2008.

[21] KRANITZ, F., BENSI, S.: The BUWAL method. In: Posch-Trözmüller, G. (Ed.): Second Scientific Report to the INTERREG IV A project MASSMOVE - Minimal standards for compilation of danger maps like landslides and rock fall as a tool for disaster prevention. Attachment 4 to the second progress report, Geological Survey of Austria, Wien, 2009.

[22] Malet, J.-P.; Thiery, Y.; Maquaire, O.; Sterlacchini, S.; van Beek, L.P.H.; van Asch, Th.W.J.; Puissant, A.; Remaitre, A.: Landslide risk zoning: What can be expected from model simulations? JRC Expert Meetings on Guidelines for Mapping Areas at Risk of Landslides in Europe 23-24 October 2007, JRC, Ispra EU, 2007.

[23] MAYER, K.: Maßnahme 3.2a „Schaffung geologischer und hydrologischer Informationsgrundlagen“. Vorhaben „Gefahrenhinweiskarte Oberallgäu“. Bayerisches Landesamt für Umwelt, München 2007.

[24] MAZENGARB, C.: The Tasmanian Landslide Hazard Map Series: Methodology. Tasmanian Geological Survey Record 2005/04, Mineral Resources Tasmania, 2005.

[25] MIDDELMANN, M. H. (ED.): Natural Hazards in Australia: Identifying Risk Analysis Requirements. Geoscience Australia, Canberra 2007.

[26] MORTON, D.M., ALVAREZ, R.M., CAMPBELL, R.H.: Preliminary soil-slip susceptibility maps, southwestern California. USGS Open-File Report OF 03-17, Riverside, 2003.

[27] NÖSSING, L.: Gefahrenzonenplanung in Südtirol. Vortrag im Rahmen des Landesgeologentages 2009, 26.2.2009, St. Pölten 2009.

[28] OLLER, P., GONZALEZ, M., PINYOL, J., MARTINEZ, P.: Hazard mapping in Catalonia. Vortrag Workshop AdaptAlp, 17.3.2010, Bozen 2010.

[29] POSCH-TRÖZMÜLLER, G.: AdaptAlp WP 5.1 Hazard Mapping - Geological Hazards. Literature Survey regarding methods of hazard mapping and evaluation of danger by landslides and rock fall. Final Report, Geologische Bundesanstalt, Wien, 2010

[30] RAETZO, H.: Hazard assessment in Switzerland – codes of practice for mass movements, International Association of Engineering Geology IAEG Bulletin, 2002.

[31] REATZO, H. & LOUP, B.: Geological hazard assessment in Switzerland (this issue)

[32] RAETZO, H. & LOUP, B. ET AL.; BAFU: Schutz vor Massenbewegungen. Technische Richtlinie als Vollzugshilfe. Entwurf 9. Sept. 2009.

[33] REEVES, H.: Geohazards: The UK perspective. Vortrag Workshop AdaptAlp, 17.3.2010, Bozen 2010.

[34] RUDOLF-MIKLAU F. & SCHMIDT F.: Implementation, application and enforcement of hazard zone maps for torrent and avalanches control in Austria, Forstliche Schriftenreihe, Universität für Bodenkultur Wien, Bd. 18, p. 83-107, 2004.

[35] RUFF, M.: GIS-gestützte Risikonanalyse für Rutschungen und Felsstürze in den Ostalpen (Vorarlberg, Österreich). Georisikokarte Vorarlberg. Diss. Univ. Karlsruhe, 2005.

[36] SCHWEIGL, J.; HERVAS, J.: Landslide Mapping in Austria. JRC Scientific and Technical Report EUR 23785 EN, Office for Official Publications of the European Communities, 61 pp. ISBN 978-92-79-11776-3, Luxembourg, 2009.

[37] SGD, PERSONENKREIS GEOGEFAHREN: Geogene Naturgefahren in Deutschland- Empfehlungen der Staatlichen Geologischen Dienste (SGD) zur Erstellung von Gefahrenhinweiskarten., 2007.

[38] TILCH, N.: Datenmanagementsystem GEORIOS (Geogene Risiken Österreich). Vortrag im Rahmen des Landesgeologentages 2009, 26.2.2009, St. Pölten 2009.

[39] VARNES, D.J. AND IAEG COMMISSION ON LANDSLIDES AND OTHER MASS-MOVEMENTS:Landslide hazard zonation: a review of principles and practice. The UNESCO Press, Paris, 1984.

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Zusammenfassung:In den Bergregionen treten an Steilhängen verschiedene Arten von Massenbewegungen auf, die Wasser und Sedimente mit sich führen: Muren, Bergsturz und Steinschlag. Das Ziel dieser Abhandlung ist es, einen kurzen Überblick über die vergangenen Analysen der Gefahren von Hangmassenbewegungen zu geben. Obwohl der Schwerpunkt auf Berg-stürzen liegt, können die präsentierten Ansätze auch zur Gefahrenbeurteilung von Muren und Steinschlag verwendet werden. Insbesondere Bergstürze und Muren sind sehr häufig miteinander verflochten. Im Folgenden wird „Bergsturz“ im weiteren Sinn als ein Begriff verwendet, der nicht nur auf einen Erdrutsch zu beziehen ist, sondern auch auf andere Hangmassenbewegungen.Schlüsselwörter: Bergstürze, Muren, Felssturz, numerische Ansätze, Bergsturzgefahrenanalyse

movements on slopes, including rock-fall, topples

and debris flow, that involve little or no true

sliding”. Cruden (1991) moderated the accepted

definition as “the movement of a mass of rock,

earth or debris down a slope”. Later different

working groups were established to support a

specific level of standardisation in fields related

to landslides (UNESCO, IUGS, ISSMGE, ISRM

and IAEG) and created the JTC (Joint Technical

Committee on Landslides and Engineered Slopes),

which continues to work for the standardisation

and promotion of research on landslides among

the different disciplines. A large set of definitions

was later presented by ISSMGE TC32 (Technical

Committee on Risk Assessment and Management,

2004) where international terms recognized for

hazard, vulnerability, risk and disaster can also

be found. Since these definitions were published,

many approaches have been implemented

(Einstein, 1988; Fell, 1994; Soeters and van Westen,

1996; Wu et al., 1996; Cruden and Fell, 1997; van

Westen et al., 2003; Lee and Jones, 2004; Glade et

al., 2005) allowing one to conclude that nowadays

definitions regarding landslides risk assessment

are generally accepted. The latest information of

guidelines for landslide susceptibility, hazard and

risk zoning are published by JTC-1 (2008) and van

Westen et al. (2008).

1. The “Early Ages”

The first extensive papers on the use of spatial

information in a digital context for landslide

susceptibility mapping date back to the late

seventies and early eighties of the last century.

Among the pioneers in this field were Carrara

et al. (1977) in Italy and Brabb et al. (1978) in

California. Nowadays, practically all research

on landslide susceptibility and hazard mapping

makes use of digital tools for handling spatial data

such as GIS, GPS and Remote Sensing. These tools

also have defined, to a large extent, the type of

analysis that can be carried out. It can be stated

that to a certain degree the capability of GIS

tools and the accuracy of the in-situ and remote

sensing data have determined the current state of

the art in landslide hazard and risk assessment.

Many publications about landslides and some

worldwide landslide research problems can be

found in the literature of Einstein (1988), Fell

(1994), Dai et al. (2002) and Glade et al. (2005).

2. Terminology

The term landslide was defined by Varnes and

IAEG (1984) as “almost all varieties of mass

An Overview of Approaches for Hazard Assessment of Slope Mass Movements

Ein Überblick über die Ansätze zur Gefahrenbeurteilung von Massenbewegung

Summary:In mountainous areas, various types of mass movements occur on steep slopes involving water and sediment: debris flows, landslides and rockfalls. The aim of this paper is to gather a short overview of the past analyses that dealt with the hazard assessment of slope mass movements. Although the main focus is on landslides, the approaches presented can be used to assess debris flows and rockfall hazards. In particular, landslides and debris flow are very often interlaced between each other. In the following text, the term “landslide” will be used as a term that might not always be strictly connected to only landslides but also to other slope mass movements. In a way it has a broader meaning.Keywords: landslides, debris-flows, rockfall, numerical approaches, landslide hazard assessment

MATEJA JEMEC, MARKO KOMAC

Key-note papers

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51

Landslide related data can be grouped into four

main sets, Table 1 (Soeters and van Westen, 1996).

Debris flows are processes that

have several sub-categories and different

characteristics. Debris flows are gravity-induced

mass movements, intermediate between land

sliding and water flooding, with mechanical

characteristics different from either of these

processes (Johnson, 1970). According to Varnes

(1978), debris flow is a form of rapid mass

movement of rocks and soils in a body of granular

solid, water, and air, analogous to the movement

of liquids. In the landslide classification of Cruden

and Varnes (1996), debris flows are flow-like

landslides with less than 80% of sand and finer

particles. Velocities vary between very rapid and

extremely rapid with typical velocities of 3 m/min

and 5 m/sec, respectively. Landslides and debris

flow are very often interlaced between each

other (Fig.1). In many cases, heavy precipitation

is recognised as the main cause, and thresholds

under different climatic conditions have been

empirically evaluated (Caine, 1980; Canuti et

al., 1985; Fleming et al., 1989; Mainali and

Rajaratnam, 1994; Anderson, 1995; Cruden and

Varnes, 1996; Finlay et al., 1997; Crosta, 1998;

Crozier, 1999; Dai et al., 1999; Glade, 2000;

Alcantara-Ayala, 2004; Fiorillo and Wilson, 2004;

Lan et al., 2004; Malet et al., 2005; Wen and

Aydin, 2005). Landslides may mobilise to form

debris flows by three processes: (a) widespread

Coulomb failure within a sloping soil, rock, or

sediment mass, (b) partial or complete liquefaction

of the mass by high pore-fluid pressure, and (c)

conversion of landslide translational energy to

internal vibrational energy (Iverson et al., 1997).

Key-note papers

Fig. 1: Classification of slope mass movements as a ratio of solid fraction and material type. Modified after Coussot and Meunier (1996).

Abb. 1: Klassifikation von Massenbewegungen als Verhältnis von Geschiebefraktion und Materialart. Modifiziert nach Coussot und Meunier (1996).

Data layer and types Accompanying data in tables Used methods for data collecting

1. Landslide occurrence

Landslides Type, activity, depth, dimensions, etc Fieldwork, orthophoto, satellite images

2. Environmental (preparatory) factors

Terrain mapping units Units description In-situ survey (fieldwork), satellite images

Geomorphological units Geomorphological description Ortophoto, fieldwork, high resolution DEM

Digital elevation model (DEM) Altitude classes SRTM DEM data, topographic map

Slope map Slope angle classes With GIS form DEM

Aspect map Slope direction classes With GIS form DEM

Slope length Slope length classes With GIS form DEM

Slope shape Concavity/convexity With GIS form DEM

Internal relief Altitude/area classes With GIS form DEM

Drainage density Longitude/area classes With GIS form DEM

Lithologies Lithology, rock strength, weathering process

Fieldwork and laboratory tests, archives, orthophoto

Soils and material sequences Soils types, materials, depth, grain size, distribution, bulk density

Modelling form lithological map, geomorphological map and slope map, fieldwork and laboratory analysis

Structural geological map Fault type, length, dip, dip direction, fold axis Fieldwork, satellite images, orthofoto

Vertical movements Vertical movements, velocities Geodetic data, satellite data

Land use map Land use type, tree density root depth Satellite images, orthofoto, fieldwork

Drainage Type, order and length Orthophoto, topographic map

Catchment areas Order, size Orthophoto, topographic map

Water table Depth of water table in time Hydraulic stations

3. Triggering factors

Rainfall and maximum probabilities Precipitation in time Meteorological stations and modelling

Earthquakes and seismic acceleration

Earthquakes database and maximum sesismic acceleration

Seismic data, engineering geological data and modelling

4. Elements at risk

Population Number, sex, age, etc. Statistics information

Transportation system and facilities Roads and railroad types, facilities types

Atlas, topographic map, local information

Lifeline utility system Types of lifeline network and capacity of fascilities

Atlas, topographic map, local information

Building Type of structure and occupation Topographic map, Housing information

Industry Industry production and type Atlas, topographic map, local information

Services facilitiesNumber and type of health, educational, cultural and sport facilities

Atlas, topographic map, local information

Tourism facilities Type of touristy facilities Atlas, topographic map, local information

Natural resources Area without natural resources combined Atlas, topographic map, local information

Tab. 1: Summary of data needed for landslide hazard and risk assessment. Adapted from Soeters and van Westen (1996).

Tab. 1: Zusammenfassung der Daten für Erdrutsch-Gefährdungs- und Risikoanalyse. Adaptiert von Soeters und van Westen (1996).

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van Westen and Terlien, 1996; Soeters and Westen,

1996; van Asch et al., 1999; Zaitchik et al., 2003;

Mazengarb, 2004; Schmidt and Dikau, 2004;

Mayer et al., 2010), which is based on hydrological

and slope instability models to evaluate the safety

factor. Montgomery et al. (1994, 1998 and 2000)

have attributed a great importance to precipitation

and many other investigations have also been

carried out about the relationship between rainfall

and landslides (Crozier, 1999; Lida, 1999; Dai

and Lee, 2001; Guzzetti et al., 2007). For rainfall

induced failures, these models couple shallow

subsurface flow caused by rainfalls of various

return periods, predicted soil thickness and soil

mantle landslides. Numerous studies have used

rainfall characteristics, such as duration, intensity,

maximum and antecedent rainfall during a

particular period, to identify the threshold value for

landslide initiation. Many authors (Caine, 1980;

Caine and Mool, 1982; Brabb, 1984; Cannon

and Ellen, 1985; Jakob and Weatherly, 2003)

applied the rainfall intensity duration equation

to estimate the threshold. With regard to specific

rainfall characteristics, Wieczorek and Sarmiento

(1983) used total rainfall duration before specific

rainfall intensity occurs; Govi et al. (1985) applied

total rainfall during a specific period after rainfall

starts; and Crozier (1986) utilized the ratio of

total rainfall to antecedent rainfall. Guzzetti et

al. (2004) identified the local rainfall threshold

on the basis of local rainfall and landslide record

and concluded that landslide activity in Northern

Italy initiates 8-10 hours after the beginning of a

storm. However, many other investigations have

been published about the relationship between

rainfall and landslides and attribute a large

impact to precipitation for the time duration of

landslides (Carrara, 1991; Mongomery et al.,

1994, 1998; Terlien et al., 1995; Crozier, 1999;

Laprade et al., 2000; Alcantara-Ayala, 2004; Coe

et al., 2004; Fiorillo and Wilson, 2004; Lan et al.,

2004; Wen and Aydin, 2005; Zezere et al., 2005;

Giannecchini, 2006; Jakob et at., 2006). While

some of them deal with specific cases, others are

more concerned with the statistical relationship

for creating correlations models and even produce

forecasting models based on rainfall threshold

values.

One of the relatively new methods

applied to landslide hazard and susceptibility

assessment are artificial neural network (ANN)

tools. ANN is a useful approach for problems

such as regression and classification, since it

has the capability of analyzing complex data

at varied scales such as continuous, categorical

and binary data. The concept of ANN is based on

learning form data with known characteristics to

derive a set of weighting parameters which are

used subsequently to recognize the unseen data

(Horton, 1945).

Lee et al. (2003b) developed landslide

susceptibility analysis techniques using a multi-

layered perception (MLP) network. The results

were verified by ranking the susceptibility index

in classes of equal area and showed satisfactory

agreement between the susceptibility map and

the landslide location data. Lee et al. (2003a)

obtained landslide susceptibility by using neural

network models and compared neural models with

probabilistic and statistical ones. They also show a

combination of ANN for determination of weights

used spatial probabilities to create a landslide

susceptibility index map (Lee et al., 2004). Rainfall

and earthquake scenarios as triggering factors for

landslides have been used in hazard assessment

with ANNs (Lee and Evangelista, 2006; Wang and

Sassa, 2006). Several studies recognize ANN as a

promising tool for these applications and most of

them use a Multi layer Perceptron (MLP) network

and a back propagation algorithm for training

the network (Rumelhart et al., 1986; Arora et

al., 2004; Ercanoglu, 2005; Ermini et al., 2005;

Key-note papers

and morphogenetic behaviour of the landslides,

and computing capabilities of software and

hardware tools).

Firstly, inventory analysis, which are

based on the analysis of the spatial and temporal

distribution of landslide attributes and such

inventories are the basis of most susceptibility

mapping techniques. On detailed landslide

inventory maps, the basic information for

evaluating and reducing landslide hazards on

a regional or local level may be provided. Such

maps include the state of activity, certainty of

identification, dominant type of slope movement,

primary direction, and estimated thickness of

material involved in landslides, and the dates of

known activity for each landslide (Wieczorek,

1984).

Secondly, the popular heuristic analysis

(Castellanos and van Westen, 2003; R2 Resource

Consultants, 2005; Ruff and Czurda, 2007;

Firdaini, 2008) based on expert criteria with

different assessment methods. The landslide

inventory map is accompanied with preparatory

factors to be the main input for determining

landslide hazard zoning. Experts then define the

weighting value for each factor.

Many researchers utilize statistical

analysis (Neuland, 1976; Carrara, 1983; Pike,

1988; Carrarra et al., 1991; van Westen, 1993;

Chung & Fabbri, 1999; Gorsevski et al., 2000;

Dhakal et al., 2000; Zhou et al., 2003; Saha et al.,

2005; Guinau et al., 2007; Komac and Ribičič,

2008; Magliulo et al., 2008; Miller and Burnett,

2008; Pozzoni et al., 2009; Komac et al., 2010),

where several parameter maps are surveyed to

apply bivariate and multivariate analysis. The

key of this method is the landslide inventory map

when the past landslide occurrences are needed

to forecast future landslide areas.

The next approach is deterministic

analysis (van Westen, 1994; Terlien et al., 1995;

Rockfall is one of the most common mass

movement processes in mountain regions and is

defined as the free falling, bouncing or rolling

of individual or a few rocks and boulders, with

volumes involved generally being < 5 m3 (Berger

et al., 2002). Numerous studies exist concerning

various aspects of rockfall, such as the dynamic

behaviour (Ritchie, 1963; Erismann, 1986; Azzoni

et al., 1995), boulder reaction during ground

contact (Bozzolo et al., 1986; Hungr and Evans,

1988; Evans and Hungr, 1993), or runout distances

of falling rocks (Kirkby and Statham, 1975; Statham

and Francis, 1986; Okura et al., 2000). Much

research was also done on the possible triggers

of rockfall, such as freeze-thaw cycles (Gardner,

1983; Matsuoka and Sakai, 1999; Matsuoka,

2006), changes in the rock-moisture level (Sass,

2005), the thawing of permafrost (Gruber et al.,

2004), the increase of mean annual temperatures

(Davies et al., 2001), tectonic folding (Coe and

Harp, 2007) or the occurrence of earthquakes

(Harp and Wilson, 1995; Marzorati et al., 2002).

In addition, several studies exist on the long-term

accretion rates of rockfall (Luckman and Fiske,

1995; McCarroll et al., 1998). Furthermore, since

the late 1980s, the field of numeric modelling

has become a major topic in the field of rockfall

research (Zinggerle, 1989; Guzzetti et al., 2002;

Dorren et al., 2006; Stoffel et al., 2006).

3. Numerical approaches to landslide hazard

assessment

According to Van Westen (1993), the landslide

hazard assessment methods have been divided

into four groups of analysis. We’ve added an

additional group – Artificial Neural Networks. The

selection of one method over another depends on

several factors (the data costs and availability, the

scale, the output requirements, the geological and

geomorphological conditions, the tectonogenetic

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Gomez and Kavzoglu, 2005; Wang et al., 2005;

Pradhan and Lee, 2007, 2009a, 2009b, 2009c;

Pradhan et al., 2009; Youssef et al., 2009). Ermini

et al. (2005) and Catani et al. (2005) used unique

conditions units for the terrain unit definition in

ANNs analysis. More critical analyses compare

ANN techniques with other methods such as

logistic regression, fuzzy weighing and other

statistical methods (Ercanoglu and Gokceoglu,

2002; Lu, 2003; Neaupane and Achet, 2004;

Miska and Jan, 2005; Yesilnacar and Topal, 2005;

Kanungo et al., 2006; Lee, 2007). In the neural

network method, Nefeslioglu et al. (2008) showed

that ANNs give a more optimistic evaluation of

landslide susceptibility than logistic regression

analysis. Melchiorre et al. (2006) did further

research on the behaviour of a network with

respect to errors in the conditioning factors by

performing a robustness analysis and Melchiorre

et al. (2008) improved the predictive capability

and robustness of ANNs by introducing a cluster

analysis. Neaupane and Achet (2004) used

ANN for monitoring the movement. Moreover,

Kanungo et al. (2006) showed that a landslide

susceptibility map derived from combined

neural and fuzzy weighting procedure is the best

amongst the other weighting techniques. Lui et

al. (2006) assessed the landslide hazard using

ANNs for a specific landslide typology (debris

flow), considering among the triggering factors

frequency of flooding, covariance of monthly

precipitation, and days with rainfall higher than a

critical threshold.

4. Approaches to landslide hazard assessment

The landslide susceptibility assessment is a

particular step in the landslide hazard assessment

and is usually based on the comparison of

the previously surveyed landslides and the

conditional or preparatory causal factors. With

this combination a GIS is obtained in a landslide

susceptibility map. In susceptibility analyses,

triggering causal factors are often not considered.

Some research has been done specifically related

to the landslide susceptibility assessment (Lee et

al., 2003; Sirangelo and Braca, 2004; Guzzetti

et al., 2006). Several countries have published

national landslide susceptibility maps that are

based on their national landslide inventory

(Brabb et al., 1999; Guzzetti, 2000; Komac and

Ribičič, 2008). One of the proven techniques for

landslide susceptibility assessment is the weights

of evidence (WofE) modelling. Many landslide

susceptibility have been carried out using this

method (van Westen, 1993; Fernandez, 2003; van

Westen et al., 2003; Lee and Choi, 2004; Suzen

and Doyuran, 2004; Neuhauser and Terhorst,

2007; Magliulo et al., 2008). Essentially, the

WofE method is a bivariate statistical technique

that calculates the spatial probability and odds of

landslides given a certain variable.

Many investigations have included

landslide runout in the analyses for landslide

hazard assessment. With research on landslide

runout or travel distance started in mid Nineties

of the last century (Hungr, 1995; Finlay et al.,

1999; Chen and Lee, 2000; Okura et al., 2000;

Fannin and Wise, 2001; Wang et al., 2002; Crosta

et al., 2003; Hunter and Fell, 2003; Bertolo and

Wieczorek, 2005; Hungr et al., 2005; Malet et

al., 2005; Crosta et al., 2006; van Asch et al.,

2006; Pirulli et al., 2007; van Asch et al., 2007a;

van Asch, et al., 2007b) where authors use three

types of approaches for runout analysis. These are

the empirical approach from previous landslides

and geomorphological analysis, the deterministic

approach from the geotechnical parameters and

the dynamic approach from numerical modelling

of runout.

Key-note papers

Numerical approach Basic description of approach References

Inventory analysisAnalysis of the spatial and temporal distribution of landslide attributes

Wieczorek (1984)

Heuristic analysis Based on expert criteria with different assessment methods

Castellanos and van Westen (2003);R2 Resource Consultants (2005); Ruff and Czurda (2007); Firdaini (2008)

Statistical analysisSeveral parameter maps are surveyed to apply bivariate and multivariate analysis

Neuland (1976); Carrara (1983); Pike (1988); Carrarra et al. (1991); van Westen (1993); Chung and Fabbri (1999); Gorsevski et al. (2000); Dhakal et al. (2000); Zhou et al. (2003); Saha et al. (2005); Guinau et al. (2007); Komac and Ribičič (2008); Magliulo et al. (2008); Miller and Burnett (2008); Pozzoni et al. (2009); Komac et al. (2010)

Deterministic analysis

rainfall

Apply hydrological and slope instability models to evaluate the safety factor

Use rainfall characteristic to identify the threshold value for landslide initiation

van Westen (1994); Terlien et al. (1995); van Westen and Terlien (1996); Soeters and Westen (1996); van Asch et al. (1999); Zaitchik et al. (2003); Mazengarb (2004); Schmidt and Dikau (2004); Mayer et al. (2010)

Caine (1980); Caine and Mool (1982); Wieczorek and Sarmiento (1983); Brabb (1984); Cannon and Ellen (1985); Govi et al. (1985); Crozier (1986); Carrara (1991); Terlien et al. (1995); Montgomery et al. (1994, 1998 and 2000); Crozier (1999); Lida (1999); Laprade et al. (2000); Dai and Lee (2001); Jakob and Weatherly (2003); Alcantara-Ayala (2004); Coe et al. (2004); Fiorillo and Wilson (2004); Guzzetti et al. (2004); Lan et al. (2004); Zezere et al. (2005); Wen and Aydin (2005); Giannecchini (2006); Jakob et al. (2006); Guzzetti et al. (2007)

Artificial neural network (ANN)

Learning from data with known characteristics to derive a set of weighting parameters, which are used subsequently to recognize the unseen data

Horton (1945); Rumelhart et al. (1986); Ercanoglu and Gokceoglu (2002); Lee et al. (2003a); Lee et al. (2003b); Lu (2003); Arora et al. (2004); Lee et al. (2004); Neaupane and Achet (2004); Catani et al. (2005); Ercanoglu (2005); Ermini et al. (2005); Gomez and Kavzoglu (2005); Miska and Jan (2005); Wang et al. (2005); Yesilnacar and Topal (2005); Kanungo et al. (2006); Lee and Evangelista (2006); Lui et al. (2006); Melchiorre et al. (2006, 2008); Wang and Sassa (2006); Lee (2007); Pradhan and Lee (2007,2009a, 2009b, 2009c); Nefeslioglu et al. (2008); Pradhan et al. (2009); Youssef et al. (2009)

Tab. 2: Review of numerical approaches to landslide hazard assessment with short description of approach and references.

Tab. 2: Überprüfung von numerischen Ansätzen zur Gefahrenabschätzung von Rutschungen mit einer kurzen Darstellung des Ansatzes und Referenzen.

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Komac (2006) designed multivariate statistical

processing techniques in order to obtain several

landslide susceptibility models with data at scale

1:50,000 and 1:100,000. Based on the statistical

results, several landslides susceptibility maps

were created.

Quantitative landslide risk assessment

has been used for specific slopes or very small

areas using probabilistic methods or percentage

of losses expected (Whitman, 1984; Chowdhury,

1988). Probabilistic values (0-1) are obtained

at the expense of a certain amount of monetary

or human loss. Quantitative risk analysis and

consequent assessment uses information about

hazard probability, values of elements at risk

and their vulnerability. Among the quantitative

approaches found in literature there are some

basic similarities but also some differences

between the approaches. They include either

estimation of hazard or estimation of vulnerability

and consequences (Morgan, 1992; Einstein, 1988,

1997; Fell, 1994; Fell et al., 2005; Anderson et al.,

1996; Ragozin, 1996; Ragozin and Tikhvinsky,

2000; Lee and Jones, 2004; AGS, 2000).

5. Landslide risk management

At the end of the assessment process when

landslide susceptibility and risk assessment

have been identified, results and measures

obtained should or may be included into the

landslide risk management process governed

by decision makers to mitigate landslide risk of

the community or, at this level, several further

approaches are possible. The strategies may

be grouped into planning control, engineering

solution, acceptance, and monitoring or warning

systems. The risk assessed can be compared

with the acceptance criteria to decide upon the

landslide mitigation measures required.

Landslide (or any natural hazard for that matter)

assessment process is just one of several steps in

the (Landslide) Risk Management Cycle (RMC),

which doesn’t end at the stage where results of

assessment process are included in the RMC. RMC

is a live system where each measure/provision

results in a consequence(s) that influence(s)

further development in and steps of this cycle. In

a way we could define it as a spiral rather than as

a circular process since the same position is never

reached again.

6. Conclusion

In this paper, different approaches for the evaluation

of slope mass processes are reviewed. In general,

all analyses are based on the assumption that

historical landslides and their causal relationships

can be used to predict future ones (“past is a key

to the future”). However, we can see that many

researchers use different approaches to evaluate

landslides, debris flow or rockfall hazard risk

assessment, which mainly depend on data

availability. In developing countries, usually the

lack of financial support to produce risk assessment

maps for dangerous areas results in emphasis

on remediation measures. Whereas in countries

with high standards, the approach to the topic is

focused into prevention and into remediation if

disasters occur. In any event the obstacles related

to the availability of data are smaller each day

due to low-cost satellite information, the use of

SRTM, ASTER and Google Earth, which ease the

creation of landslide inventory databases, a basis

for any further hazard assessments. The landslide

inventory map is probably the most important data

set to work on for producing a reliable prediction

map of spatial and temporal probability for

landslides or other slope mass movements and a

necessity for any type of analyses.

Key-note papers

and the risk areas are categorized generally in

three or five classes as very high, high, moderate,

low and very low. This method is applicable for

spatial analysis using GIS and usually applied at

national or regional levels. This approach were

found in literature from Lateltin (1997), AGS

(2000), Budetta (2004), Cascini (2004), Ko Ko et

al. (2004), IADB (2005), Nadim et al. (2006).

With the semi-qualitative landslide

risk assessment approach, weights are assigned

under certain criteria, which provide numbers

as outcome, instead of qualitative classes

(0-1, 0-10 or 0-100). It could be applicable to

any scale, but more reasonably used at medium

scale. Semi-quantitative approach efficiently uses

spatial multi-criteria techniques implemented in

GIS that facilitate standardization, weighting and

data integration in a single set of tools. More

details about the weighting system are published

by Brand (1988), Koirala and Watkins (1988),

Chowdhury and Flentje (2003), Blochl and

Braun (2005), Castellanos Abella and van Westen

(2005) and Saldivar-Sail and Einstein (2007).

When implementing the semi-quantitative

model, usually the multi-criteria evaluation is

used (see references below). The input is a set

of maps that are the spatial representation on

the criteria, which are grouped, standardised

and weighted in a criteria tree. Meanwhile the

output is one or more composite index maps

indicating the completion of the model used.

The theoretical background for the multi-

criteria evaluation is based on the Analytical

Hierarchical Process (AHP) developed by Saaty

(1977). The AHP has been extensively applied

on decision making problems (Saaty and Vargas,

2001). Recently some research has been carried

out to apply AHP to landslide susceptibility

assessment (Barredo et al., 2000; Mwasi,

2001; Nie et al., 2001, Wu and Chen, 2009).

Landslide vulnerability assessment is a

fundamental component in the evaluation

of landslide risk (Leone et al., 1996). Most

publications about vulnerability are related to

hazard and risk assessment (Mejia-Navarro et al.,

1994; Leone et al., 1996; Ragozin and Tikhvinsky,

2000; van Westen, 2002; Hollenstein, 2005). The

main object of these investigations determined

the elements of risk which have impact on

structures on its surface and estimate the cost.

The vulnerability maps are expressed with values

between 0 and 1, where 0 means no damage and

1 means total loss. Generally, the vulnerability

to landslides may depend on runout distance;

volume and velocity of sliding; elements at risk

(buildings and other structures), their nature and

their proximity to the slide; and the elements

at risk (person), their proximity to the slide, the

nature of the building/road that they are in, and

where they are in the building, on the road, etc

(Finlay, 1996).

The aim of landslide hazard and risk

assessment studies is to protect the population,

the economy and environment against potential

damage caused by landslides (Crozier and Glade,

2005). Risk in this context, is seen as a disaster

that could happen in the future. The total risk

map could be obtained by combining hazard and

vulnerability and made directly or specific risk or

consequence maps can be created and analyzed

in order to achieve some preliminary conclusions.

The classification of the landslide risk assessment

is still in progress. At the moment the classification

is based on the level of quantification dividing the

landslide risk assessment methods in qualitative,

semi-qualitative and quantitative (AGS, 2000;

Powell, 2000; Walker 2000; Chowdhury and

Flentje, 2003).

The qualitative landslide risk assessment

approach is based on the experience of the experts

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Anschrift der Verfasser / Authors’ addresses:

Mateja Jemec

Dimičeva ulica 14

SI – 1000 Ljubljana, Slovenia

mateja.jemec@geo-zs.si

Marko Komac

Dimičeva ulica 14

SI – 1000 Ljubljana, Slovenia

marko.komac@geo-zs.si

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R2 RESOURCE CONSULTANTS, 2005. Upper Nehalem Watershed Analysis. Oregon Department of Forestry (Salem) 1–231.

RAGOZIN, A.L., 1996. Modern problems and quantitative methods of landslide risk assessment. Senneset K (Ed.) Landslides - Gliessements de Terrain. Rotterdam, A.A. Balkema. 1:339-44.

RAGOZIN, A.L. AND TIKHVINSKY, I.O., 2000. Landslide hazard, vulnerability and risk assessment, 8th International symposium on landslides. Thomas Telford, Cardiff, Wales.

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Both provisions were classified as binding and

directly applicable.5

In addition, the “Mountain Forests

Protocol”6 aims to preserve and, whenever

necessary, to develop or increase mountain forests

as a near-natural habitat (art. 1.1) and imposes the

duty of the Contracting Parties to give priority to the

protective function of mountain forests (art. 6.1).

The “Spatial Planning and Sustainable

Development Protocol“7 establishes the obligation

to determine the areas subject to natural hazards,

where building of structures and installations

should be avoided as much as possible (art.

9.2.e). The spatial planning policies also take

into account the protection of the environment,

in particular with regard to the protection against

natural hazards (art. 3.f).

2.2. Findings

In international law, only certain provisions

established in the protocols to the Alpine

Convention refer to the obligation to map

geological hazards. But farther-reaching,

additional substantive elaborations arising out of

these duties are not revealed before the respective

national implementation measures.

3. European law

3.1. Soil protection law

The communication from the European

Commission in 2002 about a Strategy for Soil

Protection8 aims at the further development of

1. Introduction

A glance at the legal framework on assessment

and mapping of geological hazards1 is difficult.

No coherent legal system on the

management of natural disasters can be found at

either the international or European level. Also, a

legal fragmentation can be detected at a national

level. Therefore, the art is to filter something like

a legal essence out of diverse dispersed norms,

which are often only partly related to this topic

and follow different legal approaches.2 This will

be the attempt in the following sections. Naturally,

the essay will not exceed a more or less abundant

outline of the issue.

2. International law

2.1. Alpine Convention

The Alpine Convention3 and its protocols

are the only source of international law. The

“Soil Conservation Protocol”4 provides for the

obligation to draw up maps of Alpine areas “which

are endangered by geological, hydrogeological

and hydrological risks, in particular by land

movement (mass slides, mudslides, landslides),

avalanches and floods”, and to register those areas

and to designate danger zones when necessary

(art. 10.1).

Likewise, areas damaged by erosion and

land movement shall be rehabilitated in as far

as this is necessary for the protection of human

beings and material goods (art. 11.2).

1 For the “Natural hazards profile“ of landslips, rock fall, ava-lanches and landslides, see RUDOLF-MIKLAU, Naturgefahren-Management in Österreich (2009), p. 21 et seq.2 For an overview regarding norms of prevention, see RUDOLF-MIKLAU (fn. 1), p. 97 et seq.3 BGBl. 1995/477.4 BGBl. III 2002/235.

5 BMLFUW (ed.), Die Alpenkonvention: Handbuch für ihre Umsetzung (2007), p. 112. Implementation analysis by SCHMID, Das Natur- und Bodenschutzrecht der Alpenkon-vention. Anwendungsmöglichkeiten und Beispiele, in: CIPRA Österreich (ed.), Die Alpenkonvention und ihre rechtliche Umsetzung in Österreich – Stand 2009, Tagungsband der Jahrestagung von CIPRA Österreich, 21.-22.Oktober 2009, Salzburg (2010), p. 33 et seq.6 BGBl. III 2002/233.7 BGBl. III 2002/232..

Legal Framework for Assessment and Mapping of Geological Hazards on the International, European and National Levels

Rechtlicher Rahmen für Analyse und Kartierung geologischer Gefahren auf internationaler, europäischer und nationaler Ebene

Summary:Legal standards for the assessment and mapping of geological hazards are rather scarce at the international and European level. Certain protocols to the Alpine Convention provide for the obligation to map geological hazards, but they fail to adopt substantive standards for it. At a European level, standards such as those for priority areas are only provided for in drafts such as the proposal for a Directive establishing a framework for the protection of soil or are mentioned in the Communication on the Community approach to prevent natural disasters. At a national level, there are legal provisions in connection with preventive planning on natural disasters, although the general problem on the coexistence of multiple area-related definitions persists. The extensive exposition of hazards in forestry law remains a central is-sue. The sources and materials encountered to this end are, however, not enough to derivate consistent standards and provisions for the assessment and mapping.

Zusammenfassung:Rechtliche Vorgaben betreffend Analyse und Kartierung geologischer Gefahren sind sowohl auf internationaler als auch europäischer Ebene selten. Bestimmte Protokolle zur Alpenkon-vention sehen Kartierungspflichten für geologische Risiken vor, ohne allerdings materielle Vorgaben zu treffen. Im Europarecht finden sich solche Regeln lediglich in Entwürfen wie bei den prioritären Gebieten im Vorschlag einer EU-Bodenrahmenrichtlinie oder sie werden wie im Gemeinschaftskonzept zur Verhütung von Naturkatastrophen erst in Aussicht gestellt. Auf nationaler Ebene bestehen in der Regel Rechtsvorschriften im Zusammenhang mit präventiven Planungen bei Naturgefahren, wenngleich das allgemeine Problem des Neben-einanders von mehreren gebietsbezogenen Festlegungen besteht. Als zentrale Vorschriften gelten die flächenhaften Gefahrendarstellungen im Forstrecht. Das vorgefundene Material reicht jedenfalls nicht aus, um einheitliche Standards und Vorgaben für Analyse und Kartie-rung ableiten zu können.

ROLAND NORER

Key-note papers

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3.4. Spatial planning law

Regarding the quantitative aspects of soil

protection, a separate communication on the

topic of “Planning and Environment – the

Territorial Dimension” has been announced for a

some time now. This communication should deal

with rational land-use planning, as addressed by

the Sixth Environment Action Programme.22 The

announced content, however, does not refer to a

special relevance for the prevention of landslides.

Hence, at present the only object of an integrated

and sustainable management at the EU level is

the flood prevention programme in transnational

river areas included in the European Spatial

Development Perspective (ESDP).23

3.5. Disaster law

The Communication of the European Commission

of February 200924 was another attempt to

establish measures, based on the already existing

instruments, for a Community approach on the

prevention of natural and man-made disasters.

Three key elements were mentioned for

the Community approach: creating the conditions

for the development of knowledge based disaster

prevention policies at all levels of government,

linking the actors and policies throughout the

disaster management cycle and making existing

instruments perform better for disaster prevention.

In particular, the subsection “Developing

guidelines on hazard/risk mapping” (3.1.3) is

of great interest. Here, the Commission tries

to collect and unify information about hazard/

risks by developing Community guidelines for

hazard and risk mapping, building upon existing

Community initiatives. However, these should

focus on disasters with potential cross-border

impact, exceptional events, large-scale disasters,

and disasters for which the cost of recovery

measures appears to be disproportionate when

compared to that of preventive measures. Also, a

more efficient targeting of Community funding25

is dealt with (3.3.1) by establishing an inventory

of existing Community instruments capable

of supporting disaster prevention activities, as

well as by developing a catalogue of prevention

measures (e.g. measures integrating preventive

action in reforestation/afforestation projects).

Furthermore, a Council Decision

establishing a Community Civil Protection

Mechanism25 deals with assistance intervention

in the event of major emergencies, or the

imminent threat thereof. However, a regulation

on geological mass movements similar to the EU

Directive on the assessment and management of

flood risks27, with its flood hazard maps and flood

risk maps, does not currently exist.

3.6. Findings

Some relevant regulations can be found at the

European level. However, only one of them, Cross

Compliance, is in force and affects the topic dealt

with in this essay in a rather marginal way. By

contrast, the Proposal for a Directive establishing

a Framework for the Protection of Soil, which has

been put on hold, contemplates the designation

of landslide risk areas and the establishment of

Key-note papers

22 Towards a Thematic Strategy for Soil Protection (fn. 8), Sec-tion 2.1, 6.1.; REISCHAUER, Bodenschutzrecht, in: Norer (ed.), Handbuch des Agrarrechts (2005), p. 491.23 European Commission (ed.), ESDP European Spatial Development Perspective. Towards Balanced and Sustainable Development of the Territory of the European Union (1999), Section 146.24 Communication from the Commission to the European Parliament, the Council, the European Economic ad Social Committee and the Committee of the Regions. A Community approach on the prevention of natural and man-made disasters, COM(2009) 82 final, 23.02.2009.

25 Especially the European Agricultural Fund for Rural De-velopment, the Civil Protection Financial Instrument, LIFE+, the ICT Policy Support Programme, the Research Framework Programme.26 Council Decision 2007/779/EC of 8 November 2007, OJ 2007 L 314/9.27 Directive 2007/60/EC on the assessment and management of flood risks, OJ 2007 L 288/27.

In particular, the EU Directive establishing a

Framework for the Protection of Soil turned out

to be fiercely disputed.16 Since 2007, after an

attenuated version failed to obtain the majority

in the EU Environment Council, the future of this

proposal remains uncertain.

3.2. Environmental law

In the remaining European environmental laws,

certain provisions about erosion can be found.17

However, there are no further provisions dealing

with the topic of this essay.

3.3. Agricultural law

The situation is rather similar in the area of

European agricultural law. Different standards

are included in the general provisions on direct

payments (cross compliance)18, in which there is

an obligation to maintain all agricultural land in

good agricultural and environmental condition,

such as those regarding soil erosion.19 In contrast,

the regulation on support for rural development20

includes in its Axis 2 some links with supporting

measures, such as afforestation (cf. art. 50.6).21

political commitment to soil protection in order

to achieve a more comprehensive and systematic

protection. As soil formation is an extremely slow

process, soil can essentially be considered as a

non-renewable resource.9 It proceeds to mention

eight main threats to soil in the EU10, including

“erosion” and “floods and landslides”. These are

intimately related to soil and land management.

“Floods and mass movements of soil cause

erosion, pollution with sediments and loss of soil

resources with major impacts for human activities

and human lives, damage to buildings and

infrastructures, and loss of agricultural land”.11

In 2006, the European Commission followed

suit with a Thematic Strategy for Soil Protection12

and with a Proposal for a Directive establishing

a framework for the protection of soil13, the latter

of which provides in its art. 6 for priority areas

(first draft: risk areas) with regard to landslides.

The addendum landslides “brought about by the

down-slope, moderately rapid to rapid movement

of masses of soil and rock material” fell victim to

the changes made by the European Parliament.14

Also, a programme of measures shall be adopted

within five years of the implementation of the

Directive (art. 8). A list of common elements for

the identification of areas at risk of landslides can

be found in the appendix.15 8 Communication from the Commission to the Council, the European Parliament, the Economic and Social Committee and the Committee of the Regions – Towards a Thematic Strategy for Soil Protection, COM(2002) 179 final.9 Communication from the Commission to the Council, the European Parliament, the Economic and Social Committee and the Committee of the Regions – Thematic Strategy for Soil Protection, COM(2006) 231 final, Section 1.10 Towards a Thematic Strategy for Soil Protection (fn. 8), Section 3.11 Towards a Thematic Strategy for Soil Protection (fn. 8), Section 3.8.12 Thematic Strategy for Soil Protection (fn. 9).13 Proposal for a Directive of the European Parliament and of the Council establishing a Framework for the Protection of Soil and amending Directive 2004/35/EC, COM(2006) 232 final.2..14 European Parliament legislative resolution of 14 Novem-ber 2007 on the proposal for a directive of the European Parliament and of the Council establishing a framework for the protection of soil and amending Directive 2004/35/EC, P6_TA(2007)0509.15 Annex I Section 5: soil typological unit (soil type), properties, occurrence and density of landslides, bedrock, topography, land cover, land use (including land management, farming systems and forestry), climate and seismic risk.

16 Cf. in detail NORER, Bodenschutzrecht im Kontext der euro-päischen Bodenschutzstrategie (2009), p. 17 et seq.17 Like the Directive 2000/60/EC establishing a framework for Community action in the field of water policy (“Wasserrahmen-richtlinie“), OJ 2000 L 327/1.18 Art. 4 et seq. Council Regulation (EC) No. 73/2009 estab-lishing common rules for direct support schemes for farmers under the common agricultural policy and establishing certain support schemes for farmers, OJ 2009 L 30/16.19 Art. 6 in conjunction with Annex III Regulation (EC) 73/2009; § 5.1 in conjunction with Annex INVEKOS-CC-V 2010, BGBl. II 2009/492.20 Council Regulation (EC) No. 1698/2005 on support for rural development by the European Agricultural Fund for Rural Deve-lopment (EAFRD), OJ 2005 L 277/1.21 Cf. Recital 32, 38, 41 and 44 Regulation (EC) 1698/2005. For Austrian implementation see Sonderrichtlinie zur Umsetzung der forstlichen und wasserbaulichen Maßnahmen im Rahmen des Österreichischen Programms für die Entwicklung des ländlichen Raums 2007 – 2013 „Wald & Wasser“, BMLFUW-LE.3.2.8/0054-IV/3/2007 idF BMLFUW-LE.3.2.8/0028-IV/3/2009.

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4.6. Findings

In the light of the arid gain at the international and

European legal level, at a first glance the respective

national systems seem to constitute the determining

factor, by implementing higher-ranking guidelines

or autonomously. However, norms related to the

assessment and mapping of geological hazards,

such as the law of natural disaster management

at all40, remain fragmentated between the various

regulations (“Querschnittsmaterien”). Relevant

provisions exist, primarily in forestry law with its

extensive hazard descriptions, but also marginally

in spatial planning law. This fact, however, would

not allow the development of uniform standards

and provisions for assessment and mapping of

geological hazards.41

5. Conclusion

Legal provisions regarding the assessment and

mapping of geological hazards are tenuously

sown at the international and European level.

Unlikely enough, at the national level more legal

provisions exist in connection with preventive

planning42 for natural hazards. Here, the existing

instruments partially conduct the assessment of

mass movements, although the general problem

of the coexistence of different area-related

definitions still remains.43

A convincing and coherent overall view cannot

be offered. Whereas the available legal set of tools

remains within the same course of action, no

relevant changes coming from the international

and European level are to be expected in the

near future. Admittedly, the creation of uniform

technical standards by all those involved as a

further step towards self-regulation should be

brought to mind.

Anschrift des Verfassers / Author’s address:

Univ.-Prof. Dr. Roland Norer

University of Lucerne

School of Law

Hofstraße 9

P.O. Box 7464

CH-6000 Luzern 7

Switzerland

Key-note papers

39 In Austria e.g. § 5.1.5 Styria Building Act (Steiermärkisches Baugesetz), LGBl. 1995/59, according to which a plot area is only suitable for building if the risks posed by „flood debris accumulation, rockfall, landslides” are not to be expected. From the perspective of avalanche protection see in detail KHAKZ-ADEH (fn. 37), p. 58 et seq.40 For Austria see e.g. HATTENBERGER, Naturgefahren und öffentliches Recht, in: Fuchs/Khakzadeh/Weber (ed.), Recht im Naturgefahrenmanagement (2006), p. 67 ; RUDOLF-MIKLAU (fn. 1), p. 57 and list 61 et seq., speaking of „Kompetenzlawine“.41 WEBER/OBERMEIER, Verwaltungs- und zivilrechtliche Aspek-te von Steinschlaggefährdung und –schutz, Studie im Auftrag des Bundesministeriums für Land- und Forstwirtschaft, Umwelt und Wasserwirtschaft (2008, unveröffentlicht), p. 29, suggest for Austria f.i. an extension of the competence „Wildbach- und Lawinenverbauung“ towards other natural hazards. The politi-cal feasibility seems little realistic.42 For Austria see in detail RUDOLF-MIKLAU (fn. 1), p. 129 et seq.; HATTENBERGER (fn. 40), p. 73 et seq.43 For Austria see HATTENBERGER (fn. 40), p. 84 et seq.

4.3. Soil protection law

The rules on soil protection can be divided in two

categories with different aims: on the one hand,

qualitative soil damage such as contaminating

activities and structural damages and on the

other hand, quantitative soil loss, such as soil

degradation and erosion.35 The second category

could also be of interest for mass movements.36

4.4. Spatial planning law

As a general rule, rules on areas with a higher

risk of mass movements in connection with the

designation of building sites37 or special use in

grassland can be mainly found in spatial planning

law. Further contents in this regard remain

missing.38

4.5. Building law

A similar situation applies to building law. The

suitability as a building site for areas with a higher

risk of mass movements is not given.39

action programmes. Furthermore, a Community

approach on the prevention of natural disasters

sets out guidelines for the unification of hazard

mapping in large-scale disasters.

4. National law

4.1. Forestry law

Many times, the catchment area of mountain

torrents and avalanches, as well as references to

rock fall and landslip areas, are established within

the national forestal spatial planning.28 It can even

include the layout of forests with a protective

function29 or the extensive hazard description

structured in risk levels.30 The protective effect of

the forest especially implies “the protection against

natural peril and contaminating environmental

influences as well as the conservation of the soil

against torrents and drift, boulders accumulation

and landslides”.31 Thus, forests with a direct

protective function against the above-mentioned

hazards could be signalised by means of an

administrative act (Bannwälder).32

4.2. Water law

Such regulations are limited to measures for flood

prevention33, although geological risks are at

times also included34.

35 Cf. HOLZER/REISCHAUER, Agrarumweltrecht. Kritische Analyse des „Grünen Rechts“ in Österreich (1991), p. 47; REISCHAUER (fn. 22), p. 477.

32 Such as in § 27.2.a Austrian Forestry Act 1975.

36 In Austria e.g. the pertinent national provisions only provide for land-use measures for soil in erosion areas; see § 5 Bur-genland Soil Protection Act (Burgenländisches Bodenschutz-gesetz), LGBl. 1990/87; § 27 Upper Austria Soil Protection Act 1991 (Oberösterreichisches Bodenschutzgesetz), LGBl. 1997/63; § 7 Salzburg Soil Protection Act (Salzburger Bo-denschutzgesetz), LGBl. 2001/80; § 6 Styria Agricultural Soil Protection Act (Steiermärkisches landwirtschaftliches Boden-schutzgesetz), LGBl. 1987/66.

33 In Austria e.g. Section 4 of the Water Law Act 1959, BGBl. 1959/215 (Wv).

37 In Austria e.g. § 37.1.a Tyrol Spatial Planning Act (Tiroler Raumordnungsgesetz), LGBl. 2006/27, according to which certain areas are excluded as building sites when f.i. there is a risk of „rockfall, landslide or other gravitated natural hazards”. From the perspective of avalanche protection see in detail KHAKZADEH, Rechtsfragen des Lawinenschutzes (2004), p. 37 et seq.

34 In Austria e.g. Water Construction Development Act (Was-serbautenförderungsgesetz), BGBl. 1985/148 (Wv), expressly mentions the necessary protection against “rock fall, mudflow and landslides” in the requirements for granting and allocation of federal funds to pursuit the objectives in the Act (§ 1.1.1.b).

38 F.i. the Recommendation Nr. 52 of the Austrian Spatial Pl-anning Conference (ÖROK) about preventive handling with na-tural hazards in Spatial Planning (2005) also puts an emphasis in floods. Cf. for Austria altogether KANONIER, Raumplanungs-rechtliche Regelungen als Teil des Naturgefahrenmanagements, in: Fuchs/Khakzadeh/Weber (ed.), Recht im Naturgefahrenma-nagement (2006), p. 123 et seq.

29 In Austria e.g. Forestry Development Plan (Waldentwick-lungsplan) based on § 9 Austrian Forestry Act 1975.30 In Austria e.g. hazard and risks mapping (Gefahren- und Risikokarten), here geological hazard mapping (no legal basis).31 Such as in § 6.2b Austrian Forestry Act 1975.

28 In Austria e.g. the mapping of risk areas is based on § 11 Aus-trian Forestry Act 1975, BGBl. 1975/440, in conjunction with § 7.a Regulation on the mapping of risk areas, BGBl. 1976/436, including brown areas of reference, which posed other hazards than mountain torrents and avalanches, such as rock fall and landslips. Cf. JÄGER, Raumwirkungen des Forstrechts, in: Hauer/Nußbaumer (ed.), Österreichisches Raum- und Fachplanungsrecht (2006), p. 181 et seq.; STÖTTER/FUCHS, Umgang mit Naturgefahren – Status quo und und zukünftige Anforderungen, in: Fuchs/Khakzadeh/Weber (ed.), Recht im Naturgefahrenmanagement (2006), p. 21 et seq.

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combination for one language and one country.

It is particularly relevant for this project, as the

usage of a term varies greatly within a language

depending on the region where it is used, as

it is the case for German (Germany, Austria,

Switzerland).

Easy and intuitive queries are essential

for the usability of the glossary. Although the

user friendliness mostly depends on the graphical

user interface and is hard to control through the

database design, there are still aspects that need

to be considered in conception. It is important to

determine what possible queries will be offered

to the user (e.g. a search by synonyms, case and

special character insensitive searches, etc.) and to

adapt the database design accordingly.

Editing and adding glossary terms after

the initial import should also be possible and

requires saving metadata for each entry, e.g. time

and date of the creation or the last edit of a term.

Using that information, it is easy to reconstruct the

history of an entry at a later point in time.

1. Requirements for the relational database

Before the actual database is deigned, it is essential

to assess the exact requirements for the glossary.

This eases the following conceptional work a lot

and minimizes time-consuming adjustments and

changes to the model later on.

First a list of attributes needed for a single

glossary term as well as a type for those attributes

(e.g. numbers, text, keys etc.) is to be defined.

The type of attribute determines which relations

can be saved in the database and what kind of

information can be queried using them. Every

attribute corresponds at least to one column in the

main glossary table.

The unique language to which a

term is assigned is a fundamental attribute in

a multilingual glossary. Because of the pan-

European character of the glossary, it is necessary

to specify the languages more precisely by linking

them to a specific country, resulting in a unique

Zusammenfassung:Ausgangslage und Motivation für dieses Projekt ist die schon „traditionelle“ Problematik der unterschiedlichen Verwendung und Definition der Begrifflichkeiten in der Fachliteratur zum Themenbereich Massenbewegungsprozesse. Dies hat zur Folge, dass die Arbeitsweisen der Experten in den verschiedenen geologischen Ämtern in den Projektpartnerländern nicht ein-heitlich sind und es daher immer wieder zu Missverständnissen und Schwierigkeiten bei der Abstimmung gemeinsamer Projekte kommt. Aufgrund dieser Komplexität und der Unklarheit, die speziell im deutschsprachigen Raum, aber auch europaweit, besonders im Hinblick auf die Klassifikation der Massenbewegungen existiert, soll ein mehrsprachiges Glossar erstellt werden, in welchem im Sinne der internationalen Harmonisierung in Absprache mit den einzelnen Projektpartnerländern die von den jeweiligen geologischen Ämtern verwendeten administrativen Begriffe eingestellt und in Beziehung gesetzt werden. Das gesamte Projekt gliedert sich grundsätzlich in einen technischen und einen inhaltlichen Teil, wobei die erste Projektphase vom technischen Bereich bestimmt wird. Da die harmonisierten Begrifflichkei-ten und Definitionen für alle beteiligten Länder und auch für eine breitere Öffentlichkeit zu-gänglich gemacht werden soll, wird eine relationale Datenbank erstellt, in welcher die Inhalte logisch verknüpft werden und welche zu Projektende in die LfU-Homepage integriert wird.

Internationally Harmonized Terminology for Geological Risk: Glossary (Overview)

Internationale Harmonisierung der Fachterminologie für geologische Risiken: Glossar (Überblick)

Summary:Purpose and motivation for this project are the difficulties traditionally encountered when using or defining mass movements terms in scientific papers. This results in different methods and concepts being used by geological agencies and finally leads to misunderstandings and problems in cooperative international projects. In order to tackle that complexity and ambiguity, found not only in the German-speaking geology, but generally throughout Europe, a multilingual glossary shall be created. This glossary aims at an international harmonization by providing the user with a selection of official terms used by the geological agencies in a specific country and by setting relations to similar terms employed in other countries. The resulting harmonized terms and definitions should be made available to all partners and to the general public on the internet through the Bavarian Environment Agency homepage. The first step is to design and implement the technical infrastructure required to store and query the terms. For this purpose, a relational database management system will be used as a back-end.

KARL MAYER, BERNHARD LOCHNER

Key-note papers

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The nomenclature used throughout the database

follows a simple naming convention. Depending

on the function or content of a particular table,

its name is prefixed differently. The prefix “tdta-”

stands for tables in which actual data is being stored,

“tkey-” is used for key tables (key attributes can

only take a value from a predefined set of keys) and

“trel-” for relation tables. Unique IDs are prefixed

with “id-” and meta-attributes with “meta-”.

For most of the tables the multilingual concept

required by the direct translation provides a

second table with an identical name and the suffix

“-Lng”. Those language tables hold the text values

of the different glossary terms. The first “section”

is the core of the database, with its element tables

tdtaElement and tdtaEleGlossarTerm. The glossary

terms are stored in the latter, whereas the main

element table holds additional information related

to the system and not to the glossary itself (mostly

through the usage of foreign keys).

Key-note papers

tdtaElement

PK idelement

FK4FK2FK1FK5FK3

elementtypeidworkflowstatusmetaownermetacreatoridreadaccessidwriteaccessdeletedmetamasterlang

tdtaEleGlossarTerm

PK,FK1 idelement

FK3FK4FK2

termreferenceidtopicidlangidcountrysearchtermsearchsynonyms

tdtaEleGlossarTermLng

PK,FK1, FK2PK,FK1

idelement lang

title description

tdtaElementLng

PK,FK1, PK,FK2

idelement lang

title summarymetacreatedmetalasteditmetatranslator

Fig. 3: Main tables

Abb. 3: Haupttabellen

tdtaEleGlossarTerm

PK,FK1 idelement

FK3FK4FK2

termreferenceidtopicidlangidcountrysearchtermsearch- synonyms

tdtaEleGlossarTermLng

PK,FK1 PK,FK2

idcountry lang

countryterm

tkeyLangLng

PK,FK1 PK,FK2

idcountry lang

langtermidlanguage

tkeyLanguage

PK idlanguage

langlanguagesort

tkeyLanguageLng

PK,FK1PK

idlanguagelang

languagesort

tkeyTopicLng

PK,FK1 PK,FK2

idtopic lang

topicterm

tkeyCountry

PK idcountry

countrysort

tkeyLang

PK idlang

langsort

tkeyTopic

PK idtopic

topicsort

Fig. 4: Auxiliary tables

Abb. 4: Behelfstabellen

meters. The relation to “rock fall” (i.e. similar

meaning) would be a looser one. The relations

between “cliff falls“, “block falls“, “boulder falls“

and “Felssturz“, “Steinschlag“, “Blockschlag“

could be defined in a similar manner.

(Note: the values used above are examples and do

not necessarily match any official values)

1.2 Database model

This chapter describes in detail the different

“sections” of the database. For the purpose

of clarity, the database was divided into four

“sections” or “areas” which correspond to a set of

interrelated tables. The following diagram shows

the relations between those “sections”.

Finally, the database should, to some

extent, be expandable if future needs for

extensions or additional functions arise.

1.1 Relations

The classical approach followed by most

glossaries is a single translation layer; a direct

translation of each term into exactly one term

of another language. This corresponds to a 1: n

relation between the entities (i.e. glossary terms)

in an entity-relationship model (ERM). Such a

direct translation supposes an equivalence of

the terms’ definition and meaning. In this new

glossary, the relations between the different

terms should be defined solely by their technical

meaning, resulting in two possible relations: same

meaning or similar meaning. A direct translation is

still required in order to provide the user with the

exact translation of a definition in his language.

Following example should help clarifying

the concept of “meaning” vs. “definition”:

The English term “rock fall” is usually

translated into “Felssturz” or “Bergsturz” in

German, but that translation usually doesn't

consider the effective volume transported.

However, if the technical meaning is taken into

account, “Bergsturz”, which corresponds to a

minimum volume of 106 cubic meters, would

have the same meaning as “rock avalanche”, also

characterized by volume values above 106 cubic

Fig. 2: Overview of the database model components

Abb. 2: Übersicht über die Komponenten des Datenbankmodells

Glossary

• Terms• Relations• Translation tables

Auxiliary

• Key tables• Relation tables

User Management

• Users & groups• Permissions

Metadata

• Workflow• History

Fig. 1: Example of a multilingual glossary where each term has exactly one translation in each other language. The primary key of the language table ('tdtaTermLng') is defined by its ID and language

Abb. 1: Beispiel eines mehrsprachigen Glossars, in dem jeder Begriff genau eine Übersetzung für jede weitere Sprache hat. Der Primärschlüssel der Tabelle mit dem Textinhalt ('tdtaTermLng') ist somit über ID und Sprache definiert.

tdtaTerm

PK idterm

idworkflowstatusmetacreatormetaowneridreadaccessidwriteaccessdeletedmetamasterlangmetalastedit

tdtaTermLng

PK, FK1 PK idterm lang

term description

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element, which can be displayed as a list to an

authorized user.

Finally, user and group management

defines the group(s) a user belongs to and which

read/write rights a group or a specific user owns

(through the tdtaElement table)

1.3 Data capture and import

The primary data capture is done via an Excel

table with a predefined format. This table is used

as an interface to import data records in the

database. The person responsible for filling out

this table must ensure that the relations between

the terms are set correctly. Other errors, such as

duplicate IDs, can be handled to some extent by

the database itself. The integration of the database

into the homepage from the Bavarian Environment

Agency (LfU) and a graphical user interface to

manually add or edit single terms is planned in

the final stage of the project.

2. Contents of the glossary

In view of a different use of landslide-terms in the

European countries, a multilingual glossary can help

to improve the collaboration between the experts.

Also, progress concerning the comparability of the

methods dealing with geological hazards in the

several countries is to be achieved.

Key-note papers

Fig. 6: User and group management

Abb. 6: Benutzer- und Gruppenverwaltung

trelUserGroup

PK,FK2PK,FK1

iduseridgroup

tdtaGroup

PK idgroup

groupname

description

tkeyPermissionLevelLng

PK,FK1PK

idpermissionlevellang

permissionlevelterm

tkeyPermissionLevel

PKidpermissionlevel

permissionlevelsort

tdtaElement

PK idelement

FK4

FK2

FK1

FK5

FK3

elementtypeidworkflowstatusmetaownermetacreatoridreadaccessidwriteaccessdeletedmetamasterlang

tdtaUser

PK iduser

FK1

usernamepasswordemailorganisationfullnameinactivesuperadminlastloginloginipmaingroup

For each term, following fields are available:

• 'term': the actual text value (direct

translation using the -Lng table)

• ‘reference’: source of information and date

• 'idlang' and 'idcountry': foreign keys

pointing to a unique combination of

language/country

• 'idtopic': foreign key specifying the topic of

this term

• 'searchterm' and 'searchsynonyms': used

for insensitive searches

• 'picture': paths to pictures depicting a term

The auxiliary tables are mainly key tables defining

the different languages, countries and topics used

in the main table. They also contain the relation

table used to specify relations between terms

based on a relation code (“similar” or “same”).

Metadata is partly stored in the tdtaElement table

using foreign keys. Those keys point to external

metadata tables such as tkeyWorkflowstatus

or tdtaUser, where, for example, information

about the status, author or owner of an element

are defined. tdtaHistory works similarly to a log

by saving all actions performed on a specific

Fig. 5: Metadata tables

Fig. 5: Metadata tables

tkeyWorkflowStatus

PK idworkflowstatus

workflowstatussort

tkeyWorkflowStatusLng

PK,FK1PK,FK2

idworkflowstatuslang

workflowstatus-term

tkeyLanguage

PK idlanguage

langlanguagesort

tkeyLanguageLng

PK,FK1PK

idlanguagelang

languagesort

tkeyelementActionLng

PK,FK1PK

idelementactionlang

FK2 elementactiontermidlanguage

tkeyElementAction

PK idelementaction

FK1 elementactionsortidhistory

tdtaHistory

PK idhistory

FK2

FK1

idelementlangiduserlogdatetimeinfoidelementaction

tdtaElement

PK idelement

FK4

FK2

FK1

FK5

FK3

elementtypeidworkflowstatusmetaownermetacreatoridreadaccessidwriteaccessdeletedmetamasterlang

tdtaEleGlossarTerm

PK,FK1 idelement

FK3

FK4

FK2

termreferenceidtopicidlangidcountrysearchtermseyrchsynonyms

tdtaUser

PK iduser

FK1

usernamepasswordemailorganisationfullnameinactivesuperadminlastloginloginipmaingroup

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• Falls (Sturzprozess – Steinschlag - z.B.

Steinschlag)

• Subrosion (Subrosionsprozess - z.B.

Doline)

As mentioned above, the different terms lists

will be integrated in the official homepage of

the Bavarian Environment Agency in a final step.

Therefore, the terms are collected in a predefined

Key-note papers

id term lang country definition reference topic same_rel

similar_rel

2016 Abflusslose Senke de DE

Senke ohne natürlich möglichen oberirdischen Wasserabfluss. In einem fluviatil geprägten Relief stellt sie eine Anomalie dar, die u.U ein Hinweis auf Hangbewe-gungen sein kann

LfU BayernAllgemeine Geo-morphologie

2066aktive Maß-nahmen

de DE

Schutzmaßnahme, die dem Na-turereignis aktiv entgegenwirkt, um die Gefahr zu verringern oder um den Ablauf eines Ereig-nisses oder dessen Eintretens-wahrscheinlichkeit wesentlich zu verändern. Neben den klassi-schen, punktuellen technischen Schutzmaßnahmen wie zum Beispiel Stützmauer oder Felsan-ker sind auch flächendeckende Maßnahmen im Einzugsgebiet, beispielsweise Aufforstungen oder Entwässerungen, dieser Kategorie zuzuordnen.

LfU Bayern Maßnahmen

2070Aktuelle Hang-bewegung

de DE

Hangbewegung die zum Zeit-punkt der Aufnahme aktiv oder bezüglich ihres Alters für die Untersuchungen relevant war.

LfU Bayern Rutschungs-dynamik

2029 Anbruch de DEHangbereich aus dem eine Hangbewegung ihren Ausgang nimmt.

LfU Bayern Anbruch-formen

2027 Auslöser de DE

Der Auslöser/Anlass für das Versagen eines Hanges liegt in externen Faktoren. Dieser löst eine quasi sofortige Reaktion aus, die ihrerseits wieder Aus-löser für die nächste Reaktion sein kann (Kausalitätskette). Die Auslöser reduzieren zum Beispiel die Festigkeit der im Hang anstehenden Gesteine. Mögliche Auslöser können sein: Niederschläge, Schneeschmelze, Frost- Tauwechsel, Erdbeben, Menschlicher Eingriff.

LfU Bayern Allgemeines

2092Bach-schwinde (Ponor)

de DEÖffnungen an der Erdoberfläche über die Oberflächenwasser in den Untergrund eindringt.

LfU Bayern Subrosionspro-zess/Allgemein

2079 Bergsturz de DE

Hangbewegung mit großem Volumen und hoher Dynamik, die oftmals dafür sorgt, dass die Massen am Gegenhang weit aufbranden. Volumen > 1.000.000m³.

LfU Bayern Sturzprozess - Bergsturz

Fig. 7: Extract of the “Basic-Terms-Table” in German

Abb. 7: Auszug aus der Deutschen Begriffstabelle

• General geomorphology (Allgemeine

Geomorphologie - z.B. Grat)

• General (Allgemeines - z.B.

Primärereignis)

• Fracture forms (Anbruchformen - z.B.

Bergzerreissung)

• Path of movement (Bewegungsbahnen -

z.B. Sturzbahn)

• Flow process slow (Fließprozess – langsam

- z.B. Solifluktion)

• Flow process rapid (Fließprozess – schnell

- z.B. Blockstrom)

• Flow process very rapid (Fließprozess –

sehr schnell - z.B. Murgang)

• Risk (Gefahr-Gefährdung-Risiko - z.B.

Restrisiko)

• Maps (Karten - z.B. Gefahrenkarte)

• Classification – processes (Klassifikation –

Prozesse - z.B. Sturzprozess)

• Measures (Maßnahmen - z.B. aktive

Maßnahmen)

• Slides combined (Rutschprozess –

Kombinierte Rutschung - z.B. Rutschung

mit kombinierter Gleitfläche)

• Slides rotational (Rutschprozess

– Rotationsrutschung - z.B.

Rotationsrutschung)

• Slides translational (Rutschprozess

– Translationsrutschung - z.B.

Translationsrutschung)

• Landslide dynamics (Rutschungsdynamik -

z.B. aktuelle Hangbewegung)

• Landslide features (Rutschungsmerkmale -

z.B. Rutschungkopf)

• Falls (Sturzprozess – Bergsturz - z.B.

Bergsturz)

• Falls (Sturzprozess – Blockschlag - z.B.

Blockschlag)

• Falls (Sturzprozess – Felssturz - z.B.

Felssturz)

In general, the glossary implies terms and

definitions to landslides and corresponding maps,

considering “danger, hazard and risk” caused by

several kinds of geological hazards. Due to the

“alpine – character” of the project, the glossary

contains all the languages spoken in the Alpine

region plus English and Spanish for two additional

European countries dealing with geological

hazards. Therefore, the glossary consists of the

following six languages:

• German – Germany, Switzerland, Austria

(three different lists)

• Italian – Italy

• French – France

• Slovenian – Slovenia

• Spanish – Spain (Castilian and Catalan)

• English – United Kingdom

2.1 Basic list for Germany

For the development of such a glossary, it is

necessary to create a “basic list” in which all

the desired terms and definitions are included.

Therefore a table with 92 terms and definitions

for geological hazards (in German) was drafted.

Based on this, the other language lists were

developed. More information on the approach of

this “Harmonization” is available in chapter 3.2.

In order to facilitate this process, all

the terms are structured in different topics.

This classification is very useful for simplifying

the comparability between the languages. For

example, it’s much easier to get the English term

for “Stauchwulst” if the English expert knows that

you are searching for an accumulation term. This

topical limitation helps the translator to get the

several experts on the right track.

The “basic list” is structured into the

following topics:

• Accumulation (Ablagerungen - z.B.

Schuttkegel)

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Key-note papers

Fig. 8: Extract of the “suggested-terms list” for England

Abb. 8: Auszug aus der vorgeschlagenen Begriffsliste für England

German English

id term definition reference topic topic term definition

2001 Stauchwulst

Wulst aus Gesteinsmaterial. Sie tritt vor allem an der Stirn einer Rutsch- oder Kriechmasse auf

LfU Bayern Ablagerungen accumulation toe???? accumulation at the toe/foot of the main body.

2002 MurwallMurablagerung am seitlichen Rand des Murkanales

LfU Bayern Ablagerungen accumulation accumulation at flank of the main body.

2003 Blockland-schaft

Gelände, in dem weiträu-mig Blöcke und Gesteins-schollen verteilt sind. Herkunft der Blöcke in der Regel von großen Fels- od. Bergstürzen, aber auch von Talzuschüben.

LfU Bayern Ablagerungen accumulation BlocLandscape????

Area in which blocs are shared spacious. Bloc are comming from rock col-lapses, block falls or sags.

2004 Murkegel, -fächer

Unter Murkegel sind kegel-förmige Ablagerungen v.a. an Gerinnen zu verstehen, deren Böschungswinkel meist mehr als 8-10° beträgt Sie sind oft noch durch die typischen dammartigen Wülste entlang des Randes eines ehemaligen Murstro-mes gekennzeichnet.

LfU Bayern Ablagerungen accumulationConed accumulation es-pacially at channels with a naturel slope of 8-10°.

2005Schwemm-kegel, -fächer

Schwemmkegel weisen im Gegensatz zu Murkegeln meist Böschungswinkel von weniger als 10° auf, größere Geschiebeblöcke fehlen.

LfU Bayern Ablagerungen accumulation

Coned accumulation es-pacially at channels with a naturel slope less than 10° and with no big blocs.

2006 Schuttkegel

Schuttkegel entstehen v. a. durch Steinschlag. Sie lagern sich an Steilwände und dort bevorzugt im Bereich von Steinschlagrinnen an

LfU Bayern Ablagerungen accumulation coned debris/detritus????

"coned debris/detritus" are caused by rock falls. They accumulate at the rock face.

2007 Buckelfläche

Gelände, das durch unruhige Morphologie (weiche Formen) gekennzeichnet ist.

LfU Bayern Ablagerungen accumulation undulating area????

Area which is characterized by undulating morphologie.

2008 Sturzmasse Ablagerung infolge eines Sturzprozesses. LfU Bayern Ablagerungen accumulation Accumulation caused by a

fall process.

2009 Rutschmasse Ablagerung infolge eines Rutschprozesses LfU Bayern Ablagerungen accumulation Accumulation caused by a

slide process.

2010 Rutsch-scholle

Teilweise im Verband befindlicher Gesteinskomplex, der als ganze Scholle abrutscht.

LfU Bayern Ablagerungen accumulation sliding bloc/clod/massif????

A coplex of rocks which is sliding as one bloc/clod/massif.

2011 Sturzblock Einzelblock >1m³, infolge eines Sturzprozesses. LfU Bayern Ablagerungen accumulation (fall) bloc???? One bloc (<1m³) of an fall

process.

Excel table with a unique ID for each term. This

ID is used to establish the relations between the

different languages and also to integrate these in

the relational database. Fig. 6 shows an extract

of this Excel table with the basic terms from

Germany.

2.2 “Harmonisation” of terms and methods

“…A glossary will facilitate transdisciplinary

and translingual cooperation as well as support

the harmonization of the various methods…”

(www.adaptalp.org).

Striving for “Harmonization” of regional

terms and methods seems to be a guiding principle

not only in WP 5 of the AdaptAlp project but in

multiple European cooperation projects.

In the literature, a lot of definitions are

used for the term harmonization. According to

the business dictionary, harmonization is an

“adjustment of differences and inconsistencies

among different measurements, methods,

procedures, schedules, specifications, or systems

to make them uniform or mutually compatible”

(www.businessdictionary.com).

This definition implies some important

points which are mentioned as main goals in many

projects supported by the EU. The adjustment of

differences and the achievement of compatibility

also play a major role in work package 5:

“AdaptAlp will evaluate, harmonise and improve

different methods of hazard zone planning

applied in the Alpine area. The comparison of

methods for mapping geological and water risks

in the individual countries” (www.adaptalp.org)

will be brought into focus.

Concerning the development of the

multilingual glossary for geological hazards, the

“Harmonization” is implemented by the following

approach.

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Key-note papers

are sent to the responsible persons for orientation

and preparation. Furthermore, Fig. 7 shows an

extract of the “suggested terms list” for England.

A picture paints a thousand words, therefore also

pictures and illustrations are used within the talks.

2.2.3 Data preparation and presentation

Concerning the data preparation, the main issues

are already described in the technical description

above. The central point to fully exploit the

possibilities of the database structure is the correct

setting of the relations between the different terms

(over the ID).

Regarding to the data presentation, at

this stage of the project no final results can be

shown. As mentioned in the introduction of this

article, the main output of the project will be an

online glossary which is linked to the homepage

of the Bavarian Environment Agnecy (LfU). The

layout of this web page should be clear and

simple for everyone to use. Therefore existing

online glossaries are compared and “best-

practice” examples are pulled out as inspiration.

Fig. 8 shows the “Inter Active Terminology for

Europe” glossary from the European Union which

approximately fulfils the desired criteria for the

geological hazard glossary.

3. Conclusion

As mentioned in the introduction, this article

presents no final results because the project runs

until February 2011. Nevertheless, provisional

results, theoretical and practical approaches

could be shown. The database model presented

in this article fulfils all requirements stated

by a multilingual glossary focusing on mass

movements and other geological hazards. The

multilingual concept provides the user with a

direct translation of a term in a foreign language

and sets relations to other terms based on its

technical meaning. Although the structure of the

model may seem complex, the multiple functions

offered by external tables and the stronger data

integrity fully compensate for a higher level of

complexity. To achieve this complexity, not only

the structure of the relational database but also

the contents should satisfy the guidelines. The

term “Harmonisation” is playing a central role

in the work for the glossary where the contents

are concerned. Only terms, which are officially

used by the regional responsible agencies,

are registered in the glossary and the relations

between the different expressions are also defined

by several experts. The topics in this glossary

are not defined by a translation agency, which

undoubtedly would have the linguistic ability

but not the specialist background. Due to this

approach, every involved country or region gets

the chance to determine the terms and definitions

they use and that procedure improves the overall

result. The connection to the LfU – Homepage

ensures accessibility for all interested persons.

This is an important contribution to one of the

main goals of the whole project, namely the

improvement of the cooperation by the European

countries in dealing with geological hazards.

Anschrift der Verfasser / Authors’ addresses:

Karl Mayer

Bavarian Environment Agency (LfU)

(Office Munich)

Lazarettstraße 67

80636 Munich – GERMANY

Bernhard Lochner

alpS – Centre for Natural Hazard

and Risk Management

Grabenweg 3

6020 Innsbruck - AUSTRIA

2.2.1 Basic rules

In order to tackle the complexity and ambiguity,

found not only in German-speaking geology,

but generally throughout Europe, a multilingual

glossary shall be created. This glossary aims at

international harmonization by providing the

user with a selection of official terms used by

the geological agency in a specific country and

by setting relations to similar terms employed in

other countries. Unlike many other glossaries,

which are more like dictionaries working with

direct translations; this glossary consists of terms

and definitions which are used by the official

agencies from the involved countries. So the big

difference from many other word lists is the way

of getting the topics.

2.2.2 Data acquisition

Basically the data acquisition is made during

short visits in the involved countries. Building

on the German “basic list”, in these talks “term

after term” is discussed with the respective person

responsible. With regard to linguistic problems,

each “Harmonization” is carried out with the

help of native speakers who also be well versed in

the thematic of geological hazards. The terms are

related in the following three forms:

• Same meaning (the term has the same

meaning in both languages)

• Similar meaning (the term has a similar

meaning in both languages)

• Not existing (no term with the same or

similar meaning exists)

To facilitate the harmonization process, in the

run-up to the visits, several national literature

lists with suggested terms are worked out with

the native speakers. These lists also contain short

descriptions of the desired expressions and they

Fig. 9: Screenshot of the online “Inter Active Terminology for Europe” from the EU (Source: http://iate.europa.eu)

Abb. 9: Screenshot de online „Inter Active Terminology for Europe” der EU (Quelle: http://iate.europa.eu)

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but it is not digitally available. And then there are

states that can rely on a lot of digitally available

data and are working on generating landslide

susceptibility maps. The following provides a short

summary about the efforts in the federal states.

Mass-movement inventories in Austria

Since 1978 the Geological Survey of Austria

has been gathering and displaying information

(e.g. documents, photos, inventory maps)

about gravitational mass movements and other

hazardous processes. Due to the increasing

amount of data, the Department of Engineering

Geology of the Geological Survey of Austria

developed a complex data management system

called GEORIOS. It consists of a Geographical

Information System (GIS), which is the basis for

the digital storage and display of data and overlay

of different data types. Additionally the data

management system consists of a relational data

base, which manages additional thousands of

meta-information (documents, photos etc.).

Introduction

In Austria there are several public organizations

([12] HÜBL et al. 2009) involved in the assessment

of rapid gravitational mass movements such

as rock falls and landslides. Inventories of such

events are maintained by the Austrian Torrent and

Avalanche Control (WLV) and the Geological

Survey of Austria (GBA) apart from independent

assessments done by the national railway and

road administrations.

On the level of the federal administrations,

different approaches to documenting and/or

forecasting such mass movements are being followed.

These organizations deal with those hazards using

different approaches (method and target).

As there are no legal instructions in Austria

as to how to deal with the evaluation of mass

movements, the federal states all follow a different

course of action. Also, the status of available

historical data is very different in the individual

states. In some of the federal states, almost no data

is available, others have collected a lot of data

Fig. 1: Inventory of mass movements in Austria (source Geol. B.-A.: www.geologie.ac.at)

Abb. 1: Karte der Massenbewegungen in Österreich (Quelle: Geol. B.-A.: www.geologie.ac.at)

Standards and Methods of Hazard Assessment for Rapid Mass Movements (Rock Fall and Landslide) in Austria

Standards und Methoden der Gefährdungsanalyse für schnelle Massenbewegungen (Steinschläge und Rutschungen) in Österreich

Summary:This presents the Austrian approach for the documentation and prediction of landslides and rock falls from various inventories (GEORIOS - Geological Survey, Torrent and Avalanche Control, inventories of the federal states) via the hazard zone planning leading to the development of process related susceptibility maps. The different legal obligations of the respective organizations leads to different results regarding the type, the extent and the quality of the expertise.

Zusammenfassung:Der „österreichische“ Weg zur Erfassung von historischen bzw. zur Vorhersage von zukünftigen Steinschlagprozessen und Rutschungen von den verschiedenen Ereigniskatastern (GEORIOS – Geologische Bundesanstalt, Wildbach- und Lawinenkataster, Ereigniskataster der Länder) über die Gefahrenzonenplanung bis zur Erstellung von Prozessdispositionskarten wird darge-stellt. Dabei sind unterschiedliche gesetzliche Verpflichtungen und Zielsetzungen für die damit befassten Organisationen maßgeblich für die Art, den Umfang und die Qualität der erreichten Aussagen.

MICHAEL MÖLK, THOMAS SAUSGRUBER, RICHARD BÄK, ARBEN KOCIU

Hazard assessment and mapping of mass-movements in the EU

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The Austrian Torrent and Avalanche Control (WLV)

also maintains an inventory covering torrential

floods, avalanches, landslides and rock falls – the

so called “Wildbach- und Lawinenkataster”.

Standards of susceptibility/hazard

assessment in Austria

Because of the lack of a regulatory framework

or technical standard concerning landslides and

rock falls in Austria - only the course of actions

concerning floods, avalanches and debris flows

are regulated by law (ordinance of hazard zone

mapping,[33] RUDOLF-MIKLAU F. & SCHMIDT

F., 2004) - the federal states all follow a different

course of action.

For example, in Vorarlberg risk maps

(susceptibility map, vulnerability map, risk map)

were produced in the course of a university

dissertation ([34] RUFF, 2005). For modelling,

bivariate statistics (for landslides) and cost

analysis (for rock fall) were used, working with a

25x25m raster. The susceptibility, meaning spatial

susceptibility, is presented in 5 classes (very low,

low, medium, high, very high). The inventory map

is included in the susceptibility map. On the other

hand, the local department of the Austrian Service

for Torrent and Avalanche Control (WLV) creates

“hazard maps” within the “hazard zoning plan”.

In Upper Austria, Lower Austria,

Burgenland and Carinthia, different approaches

are chosen to develop susceptibility maps

(different scales, processes) derived from existing

data sets and maps ([30] POSCH-TRÖTZMÜLLER

G., 2010): Main focus of Burgenland is

concentrated on shallow landslides with an

annual rate of movement of 1-2cm. For the

prediction of landslide susceptibility based on

morphological and geological factors, the method

called “Weights of Evidence” was chosen ([15]

KLINGSEISEN et al., 2006). Three (respectively

4) hazard zones were classified ([“high Hazard”],

“hazard”, “hazard cannot be excluded”, “no

hazard”, [15] KLINGSEISEN et al., 2006). In

Lower Austria up until now the susceptibility maps

have been created using a heuristic approach

based on geological expertise, historical data and

interpretation of DEM and aerial photos. Three

to ten classes of susceptibility are delineated at

a scale ranging from 1:50,000 to 1:25,000 ([36]

SCHWEIGL & HERVAS 2009). To offer assistance

for the municipalities in land-use planning,

landslide susceptibility maps were generated for

the major settled areas in Upper Austria (OÖ).

For each type of mass movement, the priority,

which is a susceptibility class, was evaluated on

the basis of the intensity and the probability of an

event. The priority was classified in 3 stages (high

– medium – low; [18] KOLMER, 2005). As these

maps include the intensity and the frequency of

mass movements, they can be called “hazard

maps” by definition. Nevertheless it has to be

Fig. 4: WLV-Inventory of mass movements in Austria (source: www.die-wildbach.at)

Abb. 4: Ereignisdatenbank der WLV (Quelle: www.die-wildbach.at)

• The inventory map/event map

(“Ereigniskarte”) contains only information

about processes for which an event date is

known (5W–questions: What, When, Where,

Who, Why). The symbols are correlated to

process type and magnitude (triangle – small

events, pentagon – great events).

• The thematic inventory map contains

only information related to a type of

process, categorized according to the

quality of the data.

The database includes detailed

information about the mass movements (geology,

hydrology, geometric and geographical data,

studies or tests carried out, mitigation measures)

and the source of information (archives, etc.), and

also information about who carried out the field

work and added the data into the database.

There are already 22,000 mass

movements stored in the database. The

compilation of a part of the mass movements

in Austria is publicly accessible via the internet

(www.geologie.ac.at) in German and English.

However, the web application includes only

events such as slides, rock falls, or more complex

mass movements which have been published

already in the media or the internet and are freely

available for everyone ([16]KOCIU et al 2007).

An engineering geological database, as

well as a bibliographical database is also included

in the GEORIOS system.

In cooperation with the Geological

Survey of Carinthia, the Geological Survey of

Austria has created not just one “inventory map”,

but a “level of information”, as is explained in the

following ([17] KOCIU et al 2010):

Level of information:

• Process index map, map of phenomena

(“Prozesshinweiskarte”, “Karte der

Phänomene”): These kinds of maps can have

different scales (1:50,000 and bigger) and

can be of varying quality with information

about process areas as phenomena of mass

movements that have already happened.

• The event inventory (“Ereigniskataster”)

records only those processes for which an

event date is known (5W–questions), it is

independent of a scale and can contain

processes without information on location.

In Carinthia, a digital landslide inventory

was created with historical events of the

last 50 years ([1] BÄK et al 2005).

Hazard assessment and mapping of mass-movements in the EU

Fig. 2: Event inventory of Carinthia with 5W-questions and quality remarks MAXO (M-sure; A-estimate; X-uncertain; O-unknown)

Abb. 2: Ereignisdatenbank von Kärnten mit 5W-Fragen und Qualitätskriterien „MAXO“

Fig. 3: Event map of Carinthia (brown – landslides; blue – earth flow; red – rock fall; green – earth fall)

Abb. 3: Ereigniskarte von Kärnten

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events, a thorough mapping of the phenomena

involved and an accurate interpretation of the

failure with the subsequent processes.

The WLV is legally obliged to do an

inventory of all events regarding natural hazards,

such as torrential processes, avalanches, rock-falls

and landslides in the so called “Wildbach- und

Lawinenkataster – WLK” ([8] Forstgesetz 1975).

The GBA defines its very own tasks, among others:

“the assessment and evaluation of geogenically

induced natural hazards". These inventories

(WLV, GBA, geological surveys of provinces like

Carinthia) are established to guarantee a complete

documentation of processes and events that can

eventually endanger infrastructure and/or people.

The data collected in the inventories allow for

better information and further evaluation of where,

when, how often and with which intensities those

events took place. These inventories can form

an important basis for the elaboration of hazard

maps and related hazard zones, which give the

authorities good evidence to optimize land-use

planning and avoid areas that tend to be exposed

to natural hazards. For already developed areas,

the assessment of the type of process, magnitude,

run-out, location, frequency etc. allows for a better

priority-rating and design of mitigation measures.

The elaboration of hazard zone maps

([8] Forstgesetz 1975 and [2] BGBl. 436/1976)

for potentially endangered zones caused by

natural hazards (except flooding by rivers and

earthquakes, which are done by other authorities)

for all communities is the task of the Austrian

Torrent and Avalanche Control (WLV).

The delineation of potential emmission-

zones of rapid mass movements, such as rock falls

and landslides, are not mandatory and therefore

can be illustrated as “brown hazard indication

areas” by the WLV.

The legal implication of these indication

areas lies in the obligation of the authorities

issuing building permits to consult an expert to

evaluate the hazard for the planned construction

site explicitly, otherwise the community can be

excluded from public funding for the financing of

mitigation measures in the future.

Standards, guidelines, official and legal documents

Several standards issued by the IAEG (Internat.

Association of Engineering Geology –UNESCO

Working Party of World Landslide Inventory

[42] to [47]) exist for the documentation and

classification of landslides. Furthermore, for the

documentation of landslide and rock fall events

(avalanches and torrential processes are covered

as well) there is a short course of the Universität

für Bodenkultur Wien, Dpt. f. Bautechnik und

Naturgefahren, Inst. f. Alpine Naturgefahren,

which certifies documentalists for those processes.

For the assessment and evaluation of rock

fall processes and the design of protection

measures an Austrian Standard is currently under

development ([28] ONR 24810: Technischer

Steinschlagschutz).

State of the art in the practice

The code of practice is to be brought up to the

state of the art due to the absence of binding

standards. The state of the art according to the

“Wasserrechtsgesetz WRG 1959 §12a(1)” is

defined in Austria as the following: The use of

modern technological methods, equipment and

modes of operation with proven functionality

which represent the status of progress based on

relevant scientific expertise.

Rock fall hazard assessment

The state of the art regarding the assessment and

evaluation of hazard for rock fall processes can

Hazard assessment and mapping of mass-movements in the EU

For a small study area in Styria, the Geological

Survey of Austria generated a susceptibility map

for spontaneous landslide (soil slips and earth

flows) at a scale of 1:50,000 using neural network

analysis ([35] SCHWARZ et al., 2009). Any

susceptibility class is not a ranking of the degree

of slope stability, but a description of the relative

propensity/probability of a landslide of a given

type and of a given source area to occur.).

At the Geological Survey of Austria

(GBA), susceptibility maps in different scales and

with different methods (heuristic approach, neural

network analysis) have already been generated. ([17]

KOCIU et al., 2010, [21] MELZNER et al., 2010,

[38] TILCH et al., 2009, [39] TILCH et al., 2010, [40]

TILCH et al., 2010, [41] TILCH et al 2009).

Legal situation, requirements by the law,

responsibility of different authorities

The key feature for susceptibility/hazard

mapping is a good documentation of historic

taken into account that the method of generating

these maps included neither field work nor remote

sensing techniques. The method of assessment is

based solely on geological expertise.

Using the digital geological map of

Carinthia (1:50,000), the inventory map of mass

movements (landslides and rock falls), DEM

(10m x10m raster), land-use and lithological-

geotechnical characteristics of bedrock and

unconsolidated sediments, process-related

susceptibility maps for Carinthia were generated in

a collaboration of the Geological Survey of Austria

(GBA) and the Geological Survey of Carinthia at

a scale of 1:200,000 ([1] BÄK et al., 2005). Of

course these maps still lack information about

intensity and recurrence period or probability of

occurrence. Due to the imprecision of input data

used, the accuracy of predictions regarding the

susceptibility for rapid mass-movements based on

maps like the ones mentioned above is limited.

Fig. 5: Susceptibility map for spontaneous shallow landslide at Gasen – Haslau ([35] Schwarz et al 2009).

Abb. 5: Dispositionskarte für spontane, flachgründige Rutschungen im Bereich Gasen-Haslau ([35]Schwarz et al 2009).

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Landslide hazard assessment

General

Landslides present complex natural phenomena

for both the variability of processes and the

dimensions. A landslide may exhibit a translational

sheet slide of some square meters involving the

ground surface or a deep seated mass movement

of several cubic kilometres.

Rapid landslides with reference to [6]

CRUDEN & VARNES (1996) feature velocities

of some metres per minute to several meters per

second. In Austria, the main processes exhibit

different slides and debris slides. Very rapid to

rapid flow slides, which one can find for example

in Scandinavia or in Canada, have no relevance

in Austria.

Slides include rotational, translational

and compound slides. Rotational slides own a

circular sliding surface, which results from shear

failure in relatively homogenous rock or soil of low

strength. Translational

slides take place in

rock on forgiven more

or less planar features

like bedding planes,

joints etc. The failure

results when the shear

resistance on the plane

is exceeded. Relatively

often one can find

these slides in the soil

cover of the ground,

called sheet slides,

where the sliding

surface is formed by a

weak clay layer, such

as a gley horizon in the

range of groundwater

fluctuations.

The combination of a rotational and a translational

sliding mechanism is called a compound slide.

These may develop in horizontally stratified soils

and rocks, where the upper part of the slope shows

a rotational failure which is constrained by a plane

of weakness at the base (e. g. a claystone layer).

A process that frequently can be observed

in Austria are debris slides (e. g. Gasen and Haslau

2005, Vorarlberg). These failures occur in porous

soils, especially after extraordinary water input

resulting from precipitation and/or snow melt

leading to an excess of pore water pressure. The

mass movement often starts as a rotational slide,

which turns into a debris flow down slope.

When assessing landslide hazards, it

is important to distinguish between preparatory

factors and the triggers ([46] WL/WPLI 1994). The

triggering of the occurrence of a mass movement is

the last step of destabilization over a longer period

of time. Concerning [37] THERZAGHI (1950) the

stability of slopes is stated by the factor of safety,

which is expressed by the ratio between driving

Fig. 7: An Example of changes of the factor of safety with time after [46] WL/WPLI (1994)

Abb. 7: Beispiel für die Veränderung der Sicherheit eines Einhanges über die Zeit, nach [46] WL/WPLI (1994)

For the design of mitigation measures, a

probabilistic approach is going to be defined

as a standard procedure in Austria ([28] ONR

24810) following the concept of partial factors of

safety ([26] EUROCODES) for actions/resistances

and varying accepted probabilities of failure

depending on the casualty and reliability-classes

of [27] Eurocode 0.

be described by the following workflow. The

methods to be applied are just roughly described,

for a detailed description see the cited literature.

Depending on the objective of the assessment, the

tools to be applied may vary in respect to the scale

of the result, being more coarse at regional scale

and detailed at slope-scale.

Standard procedure for the assessment of rock fall

hazards (best practice):

Preparation

• Definition of the boundaries of the project

area in compliance with the stakeholder

• Acquisition of basic data (topografic maps,

geology, land use, literature, studies etc.)

• Collection of historic event information

(written and oral)

Field work:

• Collection of properties of the forest (if

relevant), identification (by field work and/

or according to e. g. [12] JABOYEDOFF

1999) and

• Evaluation of detachment areas

description of discontinuities

(type, dip/direction, opening, filling …),

properties of rock mass,

relevant failure mechanisms,

probabilistic distribution of

joint-bordered rock bodies

• Scree slopes: block-size distribution

(statistics)

• Analysis of rock fall processes ([22]

MELZNER et al 2010, [23] MELZNER et al

2010, [24] MÖLK 2008):

Rough estimation of run out e. g. by

shadow angle (regional scale)

2D or 3D modelling (probabilistic):

provides run out length, energy and

bouncing-height distributions for slope-

scale problems

Fig. 6: Delineation of potential conflict areas at regional extent using an empirical model ([21] Melzner et al 2010).

Abb. 6: Abgrenzung potenzieller Wirkungsbereiche mittel ein-fachen empirischen Modellansätzen ([21] Melzner et al 2010).

Hazard assessment and mapping of mass-movements in the EU

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and an evaluation of the mechanical model.

Furthermore, a monitoring allows the prediction

of failure time under certain circumstances (e.g.

[9] FUKUZONO 1985, [19] KRÄHENBÜHL

2006, [32] ROSE & HUNGR 2007)

Future development

The development of forecast-models for the

prognosis of the location and/or time of rapid

gravitational mass movements to take place

or even the meteorological settings which will

trigger such events is at an early stage. Due to

the fact that the authorities are strongly asking for

such tools, many practitioners and scientists are

focusing on that topic.

The multitude of parameters influencing

the development of the erosion processes in

question will keep the stakes high and will not

allow for providing the authorities with the accurate

models they ask for within a considerable time.

Given the necessary detailed parameters, such as

geology, hydrogeology, geotechnical parameters

etc., triggering, influencing or allowing for the

processes in question are at hand, and all the

necessary models are developed, it is highly likely

that they will work in certain regions with similar

or corresponding geological, morphological and

meteorological conditions only.

The accuracy of these models will

necessarily depend highly on a thorough

calibration with well-documented events.

This emphasizes the necessity of a consistent

documentation of events, to provide the model-

developers with calibration data.

This means that the expertise of experts

applied at defined locations with all the necessary

field work and assessment of natural parameters,

fed in apt models will not become obsolete in

the near and very probably not even in the far

future. Models showing the disposition of a given

environment to tend to mass-movements and

also forecasting the location, time and run-out

of such processes will be a precious tool for the

experts although a replacement of a thorough

evaluation of the conditions on site is not to be

expected anytime.

Anschrift der Verfasser / Authors’ addresses:

Michael Mölk

Forsttechnischer Dienst für

Wildbach und Lawinenverbauung,

Geologische Stelle

Liebeneggstr. 11

6020 Innsbruck

michael.moelk@die-wildbach.at

Thomas Sausgruber

Forsttechnischer Dienst für

Wildbach und Lawinenverbauung

Geologische Stelle

Liebeneggstr. 11

6020 Innsbruck

thomas.sausgruber@die-wildbach.at

Richard Bäk

Abt. 15 Umwelt

Geologie+Bodenschutz

Flatschacher Straße 70

9020 Klagenfurt

richard.baek@ktn.gv.at

Arben Kociu

Geologische Bundesanstalt

Fachabteilung Ingenieurgeologie

Neulinggasse 38

1030 Wien

arben.kociu@geologie.ac.at

Hazard assessment and mapping of mass-movements in the EU

State of the art in landslide assessment

For several years, high resolution Lidar data

have been available for most regions in Austria

bearing landslide activity. They are a powerful

tool to recognize geomorphological structures

of landslides ([49] ZANGERL et al., 2008). A

main advantage of Lidar data in comparison

to conventional photos is the information on

shaded areas and of areas covered with wood.

Additionally, remote sensing systems (e.g.

airborne and satellite-based multispectral and

radar images) provide information on unstable,

slowly creeping slopes, which may fail and

transfer into a rapid moving masses ([31] PRAGER

et al., 2009).

Until recently, susceptibility/hazard

maps in Austria were often made on demand.

For some years authorities (LReg Kärnten, WLV

Oberösterreich und Vorarlberg) are going to make

comprehensive hazard maps giving a basis on

decision-making for land use and development.

Landslide inventories (databases of WLV, GBA,

several federal states) in combination with GIS

applications are used to get rapid information to

areas prone to landslides.

Collected surface data in combination

with subsurface data gained from trenches

and boreholes or seismic refraction, ground-

penetrating radar and electrical resistivity profiles

allow for the drawing of an underground-model

and deduce the type of failure mechanism which

is most likely to occur.

Geotechnical data are also required

to assess the factor of safety and the probability

of failure by means of analytical calculations

or numerical modelling (e.g. [29] Poisel et al.

2006). Additional information on the process

can be provided by a monitoring system. This

serves as a check for the taken assumptions

forces and resisting forces. Stable slopes feature a

factor of safety over one, meaning that the resisting

forces exceed the driving forces. If the driving

forces are greater than the resisting forces the slope

fails, i.e. the factor of safety drops under one.

Fig. 5 ([46] WL/WPLI 1994) shows the

development of a stable slope to one that fails.

Since the slope is exposed to weathering, erosion

processes etc. the factor of safety of the slope

decreases to the point where it is close to failure

(marginally stable). At this point the slope is

susceptible to many triggers.

When assessing landslide hazard the

following information is needed regarding the

ground conditions:

• geology and structures

• hydrogeology,

• type of process

• velocity of the process

• geotechnical properties of materials

involved

• potential role of human activities (triggers?).

State of the practice in landslide assessment

Conventional methods are based on observations

of potentially unstable slopes. Aerial photos,

both stereographic and orthophotos, have been

used since decades to detect these slopes by

characteristic geomorphological phenomena in

combination with available geological maps ([4]

BUNZA 1996, [14] KIENHOLZ 1995). This first

analysis is completed by mapping in the field. The

data are commonly presented in landslide hazard

maps, which show the spatial distribution of

different hazard classes. Additionally chronicles,

which occasionally exist at the town halls, turned

out to be very useful.

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[36] SCHWEIGL, J.; HERVAS, J. (2009): Landslide Mapping in Austria. JRC Scientific and Technical Report EUR 23785 EN, Office for Official Publications of the European Communities, 61 pp. ISBN 978-92-79-11776-3, Luxembourg, 2009.

[37] TERZAGHI, K. (1950): Mechanism of landslides. Geological Society of America. Berkey Volume 1950, 83-124

[38] TILCH, N. (2009): Datenmanagementsystem GEORIOS (Geogene Risiken Österreich). Vortrag im Rahmen des Landesgeologentages 2009, St. Pölten 2009.

[39] TILCH, N. (2010): Räumliche und skalenabhängige Variabilität der Datenqualität und deren Einfluss auf mittels heuristischer Methode erstellte Dispositionskarten für Massenbewegungen im Lockergestein - eine Fallstudie im Bereich Niederösterreichs –, 12. Geoforum Umhausen 14.-15.10.10, Niederthai, (http://www.geologie.ac.at/pdf/Poster/poster_2010_geoforum_tilch.pdf).

[40] TILCH, N. (2010):Erstellung von Dispositionskarten für Massenbewegungen – Herausforderungen, Methoden, Chancen, Limitierungen.- Vortrag Innsbrucker Hofgespräche 26.05.2010, Innsbruck; (http://bfw.ac.at/050/pdf/IHG_26_05_2010_Tilch_Schwarz.pdf)

[41] TILCH, N., MELZNER, S., JANDA, C. & A. KOCIU (2009): Simple applicable methods for assessing natural hazards caused by landslides and erosion processs in torrent catchments. European Geosciences Union (EGU), General Assembly, 19-24th April 2009, Vienna. (http://www.geologie.ac.at/pdf/Poster/poster_2009_egu_tilch_etal.pdf)

[42] WP/WLI - Working Party on Landslide Inventory (International Geotechnical Societies of UNESCO) (1990): Suggested Nomenclature for Landslides . – Bull. Intern. Ass. Eng. Geology, No. 41, Paris 1990

[43] WP/WLI - Working Party on Landslide Inventory (International Geotechnical Societies of UNESCO) (1990): Suggested Method for Reporting a Landslide . – Bull. Intern. Ass. Eng. Geology, No. 41, Paris 1990

[44] WP/WLI - Working Party on Landslide Inventory (International Geotechnical Societies of UNESCO) (1991): A Suggested Method for a Landslide Summary. – Bull. Intern. Ass. Eng. Geology, No. 43, Paris 1991

[45] WP/WLI - Working Party on Landslide Inventory (International Geotechnical Societies of UNESCO) (1993): A Suggested Method for describing the Activity of a Landslide. – Bull. Intern. Ass. Eng. Geology, No. 47, Paris 1993

[46] WP/WLI - Working Party on Landslide Inventory (International Geotechnical Societies of UNESCO) (1994): A Suggested Method for Reporting Landslide Causes. – Bull. Intern. Ass. Eng. Geology, No. 50, Paris 1994

[47] WP/WLI - Working Party on Landslide Inventory (International Geotechnical Societies of UNESCO) (1995): A Suggested Method for the Rate of Movement of a Landslide. – Bull. Intern. Ass. Eng. Geology, No. 52, Paris 1995

[48] WYLLIE D. C. (2006): Risk management of rock fall hazards. – Sea to Sky Geotechnique, Conference Proceedings, 25-32, Vancouver 2006.

[49] ZANGERL C., PRAGER C., BRANDNER. R., BRÜCKL E., EDER S., FELLIN W., TENTSCHERT E., POSCHER G., & SCHÖNLAUB H. (2008): Methodischer Leitfaden zur prozessorientierten Bearbeitung von Massenbewegungen. Geo.Alp, Vol. 5, S. 1-51, 2008.

[50] ZANGERL C.; PRAGER, Ch. (2008): Influence of geologcial structures on failure initiation, internal derformation and kinematics of rock slides. American Rock Mechanics Association, 08-63, (2008)

Hazard assessment and mapping of mass-movements in the EU

[20] MELZNER, S., LOTTER, M. & A. KOCIU (2009): Development of an efficient methodology for mapping and assessing potential rock fall source areas and runout zones. European Geosciences Union (EGU), General Assembly, 19-24th April 2009, Vienna. (http://www.geologie.ac.at/pdf/Poster/poster_2009_egu_melzner.pdf)

[21] MELZNER, S., DORREN, L. , KOCIU, A. & R. BÄK (2010B): Regionale Ausweisung potentieller Ablöse- und Wirkungsbereichen von Sturzprozessen im Oberen Mölltal/Kärnten. Poster Präsentation beim Geoforum Umhausen 2010, Niederthai, Tirol. (Poster download on GBA homepage www.geologie.ac.at)

[22] MELZNER, S., TILCH, N., LOTTER, M., KOÇIU, A. & BÄK, R. (2010C): Rock fall susceptibility assessment using structural geological indicators for detaching processes such as sliding or toppling. European Geosciences Union (EGU), General Assembly, 02-07 Mai 2010, Wien. (http://www.geologie.ac.at/pdf/Poster/poster_2010_egu_melzner_etal.pdf)

[23] MELZNER, S., MÖLK, M., DORREN, L. & R. BÄK (2010A): Comparing empirical models, 2D and 3D process based models for delineating maximum rockfall runout distances. European Geosciences Union (EGU), General Assembly, 02-07 Mai 2010, Vienna. (http://www.geologie.ac.at/pdf/Poster/poster_2010_egu_melzner_2d_3d.pdf)

[24] MÖLK, M. (2008): Regionalstudie Wipptal Südost: Erfassung und Darstellung von Naturgefahrenpotentialen im Regionalen Maßstab nach EtAlp Standards. Poster Präsentation beim Geoforum Umhausen 2008, Niederthai, Tirol.

[25] MÖLK M. und NEUNER G. (2004): Generelle Legende für Geomorphologische Kartierungen des Forsttechnischen Dienst für Wildbach und Lawinenverbauung, Geologische Stelle, Innsbruck, S.49, 2004

[26] ÖNORM EN 1990: Eurocode: Grundlagen der Tragwerksplanung

[27] ÖNORM EN 1997-1: Eurocode 7: Entwurf, Berechnung und Bemessung in der Geotechnik. Teil 1: Allgemeine Regeln

[28] ONR 24810: Technischer Steinschlagschutz: Begriffe und Definitionen, geologisch-geotechnische Grundlagen, Bemessung und konstruktive Ausgestaltung, Instandhaltung und Wartung. – In preparation, foreseen publication: 2011

[29] POISEL, R., ANGERER, H., PÖLLINGER, M., KALCHER, T., KITTL, H. (2006): Assessment of the Risks Caused by the Landslide Lärchberg ? Galgenwald, Austria. Felsbau 24, No. 3, S. 42-49 (2006)

[30] POSCH-TRÖZMÜLLER, G. (2010): Adapt Alp WP 5.1 Hazard Mapping - Geological Hazards. Literature Survey regarding methods of hazard mapping and evaluation of danger by landslides and rock fall. Final Report, Geologische Bundesanstalt, Wien, 2010 (www.ktn.gv.at/Verwaltung/Abteilungen/Abt.15 Umwelt, Thema Geologie und Bodenschutz)

[31] PRAGER, Ch.; ZANGERL, Ch.; NAGLER, Th. (2009): Geological controls on slope deformations in the Köfels rockslide area (Tyrol, Austria). AJES 102/2 (2009), 4-19

[32] ROSE, N.D. and HUNGR O. (2007): Forecasting potential rock slope failure in open pit mines using the inverse-velocity method. Int. Jour. of Rock Mech. and Min. Science, 44, 308-320, 2007.

[33] RUDOLF-MIKLAU F. & SCHMIDT F. (2004): Implementation, application and enforcement of hazard zone maps for torrent and avalanches control in Austria, Forstliche Schriftenreihe, Universität für Bodenkultur Wien, Bd. 18, p. 83-107, 2004

[34] RUFF, M. (2005): GIS-gestützte Risikonanalyse für Rutschungen und Felsstürze in den Ostalpen (Vorarlberg, Österreich). Georisikokarte Vorarlberg. Diss. Univ. Karlsruhe, 2005.

[35] SCHWARZ, L., TILCH, N. & KOCIU. A. (2009): Landslide sucseptibility mapping by means of artificial Neuronal Networks performed for the region Gasen-Haslau (eastern Styria, Austria) – 6th European Congress on regional Geoscientific Cartography and Information Systems. (http://www.geologie.ac.at/pdf/Poster/poster_2009_euregio.pdf)

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[2] BGBl. Nr. 436/1976: Verordnung des Bundesministers für Land- und Forstwirtschaft vom 30. Juli 1976 über die Gefahrenzonenpläne

[3] BMLFUW (2010): Richtlinie für die Gefahrenzonenplanung-LE.3.3.3/0185-IV/5/2007 vom 12. Jänner 2010[4] BUNZA, G. (1996): Assessment of landslide hazards by means of geological and hydrological risk mapping

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[7] DORREN, L., JONNSON, M., KRAUTBLATTER, M., MOELK, M. AND STOFFEL, M. (2007): State of the Art in Rock-Fall and Forest Interactions, Schweizerische Zeitschrift für Forstwesen 158 (2007) 6: S 128-141[8] Forstgesetz 1975, § 11

[9] FUKOZONO T. (1985): A new method for predicting the failure time of a slope. Proc. 4th Int. Conf. and field workshop on landslides, Tokyo, 145-150, 1985.

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[12] HÜBL, J., KOCIU, A., KRISSL, H., LANG, E., LÄNGER, E., RUDOLF-MIKLAU, F., MOSER, A., PICHLER, A., RACHOY, Ch., SCHNETZER, I., SKOLAUT, Ch., TILCH, N. & TOTSCHNIK, R. (2009): Alpine Naturkatastrophen – Lawinen-Muren-Felsstürze-Hochwässer, 120 S..- Leopold Stocker – Verlag, Graz.

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[16] KOCIU A. et al. (2007): Massenbewegungen in Österreich. – JB der Geol. B.-A. Band 147, Heft 1+2, S 215-220. – Wien 2007

[17] KOCIU, A., TILCH N., SCHWARZ L,. HABERLER A., MELZNER S. (2010): GEORIOS - Jahresbericht 2009; Geol.B.-A. Wien 2010.

[18] KOLMER, Ch. (2009): Geogenes Baugrundrisiko Öberösterreich. Vortrag im Rahmen des Landesgeologentages 2009, St. Pölten 2009.

[19] KRÄHENBÜHL R. (2006): Der Felssturz, der sich auf die Stunde genau ankündigte. Bull. Angew. Geol., 11(1), 49-63, 2006.

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step the hazard of landslides is assessed according

to the methods used in the Swiss strategy against

all natural hazards (e.g. floods, avalanches). The

hazard assessment is then integrated into land use

planning and in the risk management (3. step).

First step: Hazard identification

Landslides can be classified according to the

estimated depth of the sliding plane (< 2m: shallow;

2-10 m: intermediate; >10 m: deep) and the long

term mean velocity of the movements (< 2 cm/year:

substabilised; 2-10 cm/year: slow; > 10 cm/year:

active). These depth and velocity parameters are

not always sufficient to estimate the potential

danger of a landslide. Differential movements must

also be taken into account since they can generate

buildings to topple or cracks to open.

Rock falls are characterized by their speed

(< 40 m/s), the size of their elements (Østone < 0.5 m,

Øblock > 0.5 m) and the volumes involved. Rock

avalanches with huge volumes (v > 1million m3)

and high speed (> 40 m/s) can also happen

although these are rare.

Due to heavy rainfall, debris flows and

very shallow landslides are frequent in Switzerland.

These are moderate volume (< 20,000 m3) and

high speed features (1-10 m/s). These phenomena

are very dangerous and annually cause important

traffic disruptions and fatalities.

A map of landslide phenomena and

an associated technical report provide signs

and indications of slope instability as observed

in the field. The map represents phenomena

related to dangerous processes and delineates the

vulnerable areas.

Field interpretation of these phenomena

allows areas vulnerable to landslides to be

mapped. This is based on the observation and

interpretation of landforms, on structural and

geomechanical properties of slope instabilities,

Introduction

Switzerland is a country exposed to many natural

hazards. These hazards include earthquakes, floods,

forest fires, snow avalanches, rock falls and debris

flows. More than 6% of Switzerland is affected by

hazards due to slope instability. These areas occur

mainly in the Prealps and in the Alps. The Randa

rock avalanches of 1991 are a good example of the

potential of such hazards. Thirty million m3 of fallen

debris cut off the valley for two weeks. In another

case, a landslide was reactivated with historically

unprecedented rates of displacement up to 6 m/

day, causing the destruction of the village of Falli-

Hölli in the year 1994.

The legal and technical background

conditions for the protection against landslides

have undergone considerable changes since the

80’s. The flooding of 1987 promoted the federal

authorities to review criteria governing natural

hazard protection. The Federal Flood Protection

Law and the Federal Forest Law came into force in

1991. Their purpose is to protect the environment,

human lives and property from the damage caused

by water, mass movements, snow avalanches and

forest fires. Following the promulgation of these

new regulations, greater emphasis has been

placed on preventive measures. Consequently,

hazard assessment, the identification of protection

objectives, purposeful planning of preventive

measures and the limitation of the residual

risk are of central importance. The cantons are

now required to establish inventories and maps

denoting areas of hazards, and to take them

into account in the land use planning. For the

improvement of the inventories and the hazard

maps, the federal government provides subsides

to the cantonal authorities (50%).

In a first step the landslides are identified

and classified. During this phase inventories and

maps of phenomena are established. In a second

Geological Hazard Assessment in Switzerland

Geologische Gefahrenbeurteilung in der Schweiz

Summary:Geological hazard assessments are based on Swiss laws dealing with natural hazards. Guidelines are published by the Federal Office for the Environment (FOEN/BAFU). According to the integrated risk management, the methods are applied for all natural hazards (landslides, floods, snow avalanches). The hazard maps are dealing with five degrees: high (red), medium (blue), low (yellow), residual (yellow-white), no hazard (white).

Zusammenfassung:Geologische Gefahren werden in der Schweiz gemäß den eidgenössischen Gesetzen über den Wald und den Wasserbau erhoben und beurteilt. Dazu hat das zuständige Bundesamt (heute das Bundesamt für Umwelt BAFU) entsprechende Empfehlungen und Richtlinien veröffentlicht. Im Sinne des integralen Risikomanagements werden für alle Gefahrenprozesse vergleichbare Methoden angewendet und anschließend in der Planung umgesetzt. Das gilt für geologische Massenbewegungen, Hochwasser und Lawinen. Für diese Prozesse werden Gefahrenkarten erstellt, die immer fünf Gefahrenstufen ausscheiden: Hohe, mittlere und geringe Gefahr sowie Restgefährdung und keine Gefährdung. Daraus entstehen die roten, blauen, gelben, gelb-weiß gestreiften und weißen Zonen auf den Gefahrenkarten.

HUGO RAETZO, BERNARD LOUP

Hazard assessment and mapping of mass-movements in the EU

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allow an overview of the different natural disasters

and potential associated damage in Switzerland.

Second step: Hazard assessment of landslides

Hazard is defined as the occurrence of a potentially

damaging natural phenomena within a specific

period of time in a given area. Hazard assessment

implies the determination of the magnitude or

intensity of an event over time. Mass movements

often correspond to gradual (landslides) or unique

(falls, debris flows) events. It is sometimes difficult

to make an assessment of the return period of

a massive rock avalanche, or to predict when a

dormant landslide may reactivate.

Some federal recommendations have

been proposed in the 90’s for the management

of landslides and floods. Since 1984 similar

recommendations have already existed for snow

avalanches. Hazard maps, according to the federal

“recommendations“ (guidelines), express three

degrees of danger, represented by corresponding

colours: red, blue and yellow (Fig. 1). The various

hazard zones are delineated according to the

landslide phenomena maps, the register of slope

instability events and additional documents.

Numerical models (analysis of block trajectories,

calculations of factors of safety) may be used to

determine the extent of areas endangered by rock

falls, or to present quantitative data on the stability

of a potentially unstable area.

A chart of the degrees of danger has been

developed in order to guarantee a homogeneous

and uniform means of assessment of the different

kinds of natural hazards across Switzerland

(floods, snow avalanches, landslides…) – for

example, Fig.1 for fall processes. Two major

parameters are used to classify the danger: the

intensity, and the probability (frequency or return

period). Three degrees of danger have been

defined. These are represented by the colours red,

blue and yellow. The estimated degrees of danger

have implications for land use. They indicate the

level of danger to people and to animals, as well

as to property. In the case of mass movement,

people are considered safer inside the buildings

than outside.

A description of the magnitude of

potential damage caused by an event is based on

the identification of threshold values for degrees

of danger, according to possible damage to

property. The intensity parameter is divided into

three degrees:

High intensity: People and animals are at risk

of injury inside buildings; heavy damage to

buildings or even destruction of buildings is

possible.

Medium intensity: People and animals are

at risk of injury outside buildings, but are at

low risk inside buildings; lighter damage to

buildings should be expected.

Low intensity: People and animals are slightly

threatened, even outside buildings (except

in the case of stone and block avalanches,

which can harm or kill people and animals);

superficial damage to buildings should be

expected.

Criteria for the intensity assessment:

There is generally no applicable measure to define

the intensity of slope movements. However,

indicative values can be used to define classes

of high, mean and low intensity. Applied criteria

usually refer to the zone affected by the process,

or to the threatened zone.

For rock falls, the significant criterion is the

impact energy in the exposed zone (translation

and rotation energy). The 300 kJ limit corresponds

to the impact energy to which can be resisted

by a reinforced concrete wall, as long as the

structure is properly constructed. The 30 kJ limit

An additional distinction is made between

potential, inferred or proved events. According to

the scale of mapping (e.g. 1:50,000 for the Master

Plan, 1:5,000 for the Local Plan), this legend may

contain a large number of symbols.

Inventories: Recommendations for

the definition of a uniform Register for slope

instability events has been developed, including

special sheets for each phenomenon (landslides,

floods, snow avalanches). Each canton is currently

compiling the data for its own register. These

databases (StorMe) are transferred to the FOEN to

and on historical traces. Extensive knowledge of

past and current events in a catchment area is

essential if zones of future instability are to be

identified.

Some recommendations for the uniform

classification, representation and documentation

of natural processes have been established by the

Swiss federal administration. Consequently, the

definition of features on a natural hazard map is

based on a uniform legend for landslides, floods

and snow avalanches. The different phenomena

are represented by different colours and symbols.

RED: high hazard

•Peopleareatriskofinjurybothinsideandoutsidebuildings.

•Arapiddestructionofbuildingsispossible.

or:

•Eventsoccurringwithalowerintensity,butwithahigherprobabilityofoccurrence.Inthiscase, people are mainly at risk outside buildings, or buildings can no longer house people.

The red zone mainly designates a prohibition domain (area where development is prohibited).

BLUE: moderate hazard

•Peopleareatriskofinjuryoutsidebuildings.Riskisconsiderablylowerinsidebuildings.

•Damagetobuildingsshouldbeexpected,butnotarapiddestruction,aslongastheconstruction type has been adapted to the present conditions.

The blue zone is mainly a regulation domain, in which severe damage can be reduced by means of appropriate protective measures (area with restrictive regulations).

YELLOW: low hazard

•Peopleareatslowriskofinjury.

•Slightdamagetobuildingsispossible.

The yellow zone is mainly an alerting domain (area where people are notified at possible hazard).

YELLOW-WHITE HATCHING: residual danger

Low probability of high intensity event occurrence can be designated by yellow-white hatching. The yellow-white hatched zone is mainly an alerting domain, highlighting a residual danger.

WHITE: no danger or negligible danger, according to currently available information.

Hazard assessment and mapping of mass-movements in the EU

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correlated with recurrent meteorological conditions.

The probability of mass movement occurrence

should mainly be established for a given duration of

land use. Thus, the probability of potential damage

during a certain period of time, or the degree

of safety of a specific area should be taken into

account, rather than the frequency of dangers.

The probability of occurrence and the

return period can be mathematically linked, if

attributed to the same reference period:

p = 1 – (1 – 1/T)n

Whereby p is the probability of occurrence, n

represents the given time period (for example 30

or 50 years), and T is the return period.

For example, considering a time period of 30

years, an event with a 30-year return period has

a 64% probability of occurrence (or about 2 in

3), of 26% (or about 1 in 4) for a 100-year return

period, and of 10% (or about 1 in 10) for a 300-

year return period.

The calculation of the probability of

occurrence clearly shows that even for a rather

high return period (300 years), the residual danger

remains not significant.

In principle, the probability scale does

not exclude very rare events, neither does it

exclude the intensity scale for high magnitude

events. Hazards with a very low probability of

occurrence are usually classified as residual

dangers under the standard classification. In the

Fig. 1: Matrix for the assessment of hazards

Abb. 1: Matrix für die Gefahrenbeurteilung

RED

BLUE

YELLOW

YELL

OW

/ W

HIT

E

INTE

NSI

TY

PROBABILITY

low

high

med

ium

low very lowhigh medium

Hazard assessment and mapping of mass-movements in the EU

converted to danger classes. Other criteria as

velocity changes or accelerations (dv), differential

movements (D) and thickness of the landslide (T)

can lead to increase resp. to reduce the intensity

class as derived from the long term velocity.

For earth flows and debris flows,

the intensity depends on the thickness of the

potentially unstable layer. The boundaries defining

the three intensity classes are set at 0.5 m and 2 m.

Probability: Probability of landslides is defined

according to three classes. The class limits are set

at 30 and 300 years and are equivalent to those

established for snow avalanches and floods. The

100-year limit corresponds to a value applied in

the design of flood protection structures.

The results of probability calculations to

determine if mass movements occur remain very

uncertain. Unlike floods and snow avalanches, mass

movements are usually non-recurrent processes.

The return period, therefore, only has a relative

meaning, except for events involving stone and

block avalanches and earth flows, which can be

corresponds to the maximum energy that oak-

wood stiff barriers can resist (e.g. rail sleeper).

For rock avalanches, the high intensity class

(E > 300 kJ) is always reached in the impact zone.

The target zones affected by block avalanches

of low to medium intensity can only be roughly

delineated. Therefore, it is recommended not to

artificially delineate zones affected by low to

medium intensities.

Most landslides: A low intensity movement has an

annual mean speed of lower than 2 cm per year.

A medium intensity has a speed ranging from

one to 10 cm per year. The high intensity class

is assigned to velocities higher than 10 cm per

year and to shear zones or zones with clear

differential movements (D). It may also be assigned

if reactivated phenomena have been observed or,

if horizontal displacements greater than one meter

per event may occur. Finally, the high intensity

class can also be assigned to very rapid shallow

landslides (speed > 0.1 m/day). In the area affected

by landsliding field, intensity criteria can be directly

Phenomena Low intensity Medium intensity High intensity

Rock fall E < 30 kJ 30 < E < 300 kJ E > 300 kJ

Rock avalanche - - E > 300 kJ

Landslide v ≤ 2 cm/y v : 2-10 cm/y v>10 cm/year

dv, D, T dv, D, T dv, D, T

v > 0.1 m/day for shallow landslides; displacement > 1 m per event

Earth flows and debris flows

potential e < 0.5 m 0.5 m < e < 2 m e > 2 m

real - h < 1 m h > 1 m

E: kinetic energy; e: thickness of the unstable layer; h: height of the earthflow deposit; v: long term mean velocity, dv: variation of velocity (accelerations), D: differential movements, T: thickness of the landslide.

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The degrees of danger are initially assigned

according to their consequences for construction

activity. They must minimise risks to the safety

of people and animals, as well as minimising

as possible damage to property. In agricultural

zones, buildings affected by different degrees of

danger are constrained by the same conditions as

those in built-up areas.

Conclusions

In Switzerland legal and technical references are

published to clarify which responsibilities the

authorities have and how the assessment has to

be done in order to apply the concept of integral

risk management. The hazard map indicates

which areas are unsuitable for use, according

to existing natural hazard. The integration of

hazard maps into land use planning (including

construction conditions, building licences)

and the development of protective measures to

minimise damage to property are main objectives.

When the hazard map is compared with

existing land use conflicts may occur. Since it is

difficult or impossible to change land use, specific

construction codes are required to reach the

desired protection level. Hazard maps are also

considered in planning protective measures as

well as the installation of warning systems and

emergency plans. The federal recommendations

are on attempt to mitigate natural disasters by

restricting development on unstable areas.

Anschrift der Verfasser / Authors’ addresses:

Hugo Raetzo

Federal Office for the Environment FOEN

Bundesamt für Umwelt BAFU

3003 Bern

Schweiz

Bernard Loup

Federal Office for the Environment FOEN

Bundesamt für Umwelt BAFU

3003 Bern

Schweiz

Literatur / References:

BUNDESAMT FÜR RAUMPLANUNG, BUNDESAMT FÜR WASSERWIRTSCHAFT & BUNDESAMT FÜR UMWELT, WALD UND LANDSCHAFT, (1997). Empfehlungen, Berücksichtigung der Massenbewegungsgefahren bei raumwirksamen Tätigkeiten, EDMZ, 3000 Bern.

CRUDEN D.M. UND VARNES D.J.:Landslide types and processes. In: A. Keith Turner & Robert L. Schuster (eds): Landslide investigation and mitigation: 36-75. Transportation Research Board, special report 247. Washington: National Academy Press, 1996.

KIENHOLZ, H., KRUMMENACHER, B. et al.:Empfehlungen Symbolbaukasten zur Kartierung der Phänomene Ausgabe 1995, Mitteilungen BUWAL Nr. 6, 41 S., Reihe Vollzug Umwelt VU-7502-D, Bern 1995.

RAETZO et al.: Hazard assessment of mass movements – codes of practice in Switzerland, International Association of Engineering Geology IAEG Bulletin, 2002.

RAETZO, H. & LOUP, B.; BAFU: Schutz vor Massenbewegungen. Technische Richtlinie als Vollzugshilfe. Entwurf 9. Sept. 2009.

VARNES, D.J. and IAEG Commission on Landslides and other Mass-Movements: Landslide hazard zonation: a review of principles and practice. The UNESCO Press, Paris, 1984.

Hazard assessment and mapping of mass-movements in the EU

According to Art. 6 of the Federal Law for Land

use Planning, the cantons must identify all areas

that are threatened by natural hazards.

The cantonal Master Plan is a basic

document for land use planning, infrastructural

coordination and accident prevention. It consists

of a map and a technical report, and is based on

studies. The Master Plan allows for deciding the

following:

• It shows how to coordinate activities

associated with different land uses.

• It identifies the goals of planning and

specifies the necessary stages.

• It provides legal constraints to the

authorities in charge of land use planning.

The objectives of the Master Plan with respect to

natural hazards are:

• To early detect conflicts between land use,

development and natural hazards.

• To refine the survey of basic documents

concerning natural hazards.

• To formulate principles that can be applied

by the cantons to the issue of protection

against natural hazard.

• To define necessary requirements and

mandates to be used in subsequent

planning stages.

The constraints on Local Planning already allow

and ensure appropriate management of natural

hazards with respect to land use. The objective

of these constraints is to delineate danger zones

by highlighting restrictions, or to establish legal

frameworks leading to the same ends.

At the same time danger zones can be

delineated on the local plan with areas suitable

for construction as well as additional protection

zones.

domain of dangers related to mass movements,

the limit for a residual danger has been set for an

event with a 300-year return period.

The degree of hazard is defined in a

hazard matrix based on intensity and probability

criteria (Raetzo & Loup 2009). The resulting

hazard map is mainly used for planning (land

use), while the design of protection measures

needs more detailed investigations. In general

the methods used are related to the product,

scales and the risk in order to respect economic

criteria: low efforts are done for the Swiss

indicative map (level 1), important efforts

are done when a hazard map is established

or reviewed (level 2). Detailed analyses and

engineering calculations are foreseen for the

planning of countermeasures (level 3). Applying

this concept rising efforts for geological

investigations are planned when the assessment

on the second or third level takes place.

Third step: Land use planning and risk management

The hazard map is a basic document used in

land use planning. Natural hazards should be

taken into account particularly in the following

situations:

• Elaboration and improvement of cantonal

Master Plan and Communal Local Plans for

land use.

• Planning, construction, transformation of

buildings and infrastructures.

• Granting of concessions and planning

for construction and infrastructural

installations.

• Granting of subsidies for building and

development (road and rail networks,

residences), as well as for slope stabilisation

and protection measures.

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2) Landslide studies that have direct consequences

to land planning laws, at local scale or higher.

GIS methods allow for performing analyses

over wide areas that are useful to be included

in basin plans or master plans. National or local

laws can require standard ways to present the

results (common graphical signs on the maps,

for example).

Legal framework in Italy and Piemonte

High Level Legislation (national level)

The national Law n. 445/1908 (Transfer and

consolidation of unstable towns) and Royal

Decree R.D. n. 3267/1923 (Establishment of areas

subject to hydro-geological constrains) were the

first public regulations on land use planning. At

the beginning of ‘70s, land use management was

transferred to the regions.

The national Law n. 183/1989

introduced land use planning at a basin scale: the

government sets the standards and general aims

without fixing a methodology to analyze and

evaluate the dangers, hazards, and risks related

to natural phenomena. The same law designated

the Autorità di Bacino (Basin Authorities) whose

main goal is to draw up the Basin Plan, a tool for

planning actions and rules for conservation and

protection of the territory.

About Po basin, the last plan adopted

in 2001 is called PAI (Piano per l’Assetto

Idrogeologico or Hydrogeological System Plan

of River Po Basin). It tries to verify the geological

instability of the whole territory as regards the

land use planning through a process of upgrading

and feedback with the local urban management

plans. Moreover, all the municipalities are

classified according different risk levels, mainly

from a qualitative point of view. For landslides it

has two atlases (1:25,000 scale):

Introduction

When facing a natural hazard, risk management

can be divided in several stages:

a) danger characterization, hazard assessment

and vulnerability analysis;

b) risk evaluation and assessment;

c) risk prevention (protective works, land use

regulation, monitoring, etc.);

d) crisis and post-crisis management;

e) feedback from experience.

It is essential to properly distinguish the three

aspects of landslides studies:

• DANGER. Threat characterization (typology,

morphology even quantitative, inventory…);

• HAZARD. Spatial and temporal probability,

intensity and forecasting of evolution

(scenarios) are needed;

• RISK. Interaction between a threat having

particular hazard and human activities. We

need vulnerability and damage analysis.

These differences are theoretically well known by

all technicians but often there are some problems

when they have to be applied in a legal framework.

So, it is not so unusual to find inventory maps used

as hazard maps or damage maps called risk maps.

Therefore, we have to distinguish two situations:

1) Landslides studies that have no influence from

legal point of view. Typical cases are the studies

carried out by universities about relevant

landslides. The aim is, for example, to understand

the mechanical features of instability or to study

different ways of evolution of the phenomenon

(scenarios) in order to assess residual risk. Any

method to assess landslide hazard and risk can

be used. They include statistical, deterministic,

numerical, etc. methods for hazard and

qualitative or matrix calculus for risk. Landslide

inventory can be made by means of historical,

morphological, etc. approach.

Landslide Mapping in Piemonte (Italy): Danger, Hazard & Risk

Kartierung von Rutschungen im Piemont (Italien): Gefahren & Risiken

Summary:This paper briefly describes the legal framework of landslide danger, hazard and risk mapping in Italy and Piemonte. Laws or rules that indicate how a landslide analysis (danger, hazard, risk) has to be done, do not exist. As a general remark, it has to be observed that public legislation defines general principles and lines of conduct, functions, activities and authorities involved, while the regional administrations apply restrictions on land use through different regional laws.

Keywords: Landslide, danger, hazard, risk, Piemonte, Italy

Zusammenfassung:Diese Abhandlung beschreibt kurz den gesetzlichen Rahmen der Kartografie von Rutschungs-gefahren und -risiken in Italien und im Piemont. Es gibt keine Gesetze oder Verordnungen dar-über, wie eine Rutschungsanalyse (Gefahren und Risiken) auszuführen ist. Als eine allgemeine Bemerkung ist festzustellen, dass die öffentliche Gesetzgebung allgemeine Prinzipien und Richtlinien, Funktionen, Aktivitäten und betreffende Befugnisse festlegt, die Regionalverwal-tungen hingegen erlegen auf der unterschiedlichen landesgesetzlichen Basis Einschränkungen hinsichtlich der Bodennutzung auf.

Schlüsselwörter: Rutschung, Gefahr, Gefährdung, Risiko, Piemont, Italien

STEFANO CAMPUS

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government to give answers for development

regulation (to reduce or eliminate landslides

losses). According to the national Law n.

267/1998, the government enforced legislative

measures at the national level, including the

procedure to define landslide risk areas.

Another important aspect of the

Law n. 267/1998 regards the development of

“extraordinary plans” to manage the situations of

higher risk (R.M.E.-Aree a Rischio Molto Elevato),

where safety problems or functional damages

are possible. Local and regional authorities

are obliged to define, design and apply proper

measures to risk mitigation, with national funding.

In Piedmont, these actions have been applied in

some significant cases such as in Ceppo Morelli

(Valle Anzasca in northern part of Piemonte),

classified as a very high-risky area.

Low Level Legislation (Local Urban Development Plan)

The classification of areas made by the Po Basin

Authority is a binding act. The municipality must

adopt a new town development plan taking into

account that classification. If the municipality

wants to change PAI classification, a deep analysis

of the areas has to be done to justify new land use

destination.

Regione Piemonte Regional Law for

Urban Development L.R. n. 56/1977, which is the

main legal instrument of land use management at

a local scale, as well as the Regional Law L.R. n.

45/1989 which regulates land use modification

and transformation in areas subject to

environmental protection, divides areas in more

detailed classes having (almost) same meaning of

PAI classification.

In Piemonte, the local management plan

(required by the Regional Law L.R. n. 56/1977)

includes the danger/hazard zoning in order

to identify landslide prone areas on the basis

of geological and morphological features and

historical analysis.

In a state of emergency (as established by

the Regional Law n. 38/1978, which regulate and

organise interventions related to severe instability

phenomena), a specific article of the regional law

56/1977 (art. 9/bis) allows inhibiting or suspending

development in the involved areas. Consequently,

new land-use planning must be realised (upgrade/

revision of the local management plan).

The last integrations to this law

(Circolare del Presidente della Giunta Regionale,

n. 7/LAP/1996 and Nota Tecnica Esplicativa, n.

12/1999) introduced the concept of hazard and

risk zoning, classifying the whole territory in

different classes where land uses are precisely

regulated and defined, where building is

forbidden, where preventive measures have to be

taken, etc…

It is important to clarify that Regione

Piemonte does not have an official regional

Geological Survey. Some geological functions

are executed by Arpa Piemonte (Agency

for Environmental Protection) having two

“geological” departments: one dedicated to

Geological Informative System, research and

applied projects, the other one deals with

geological aspects of municipality urban plans.

Therefore, we produce landslide danger,

hazard and risk analyses that have not any legal

consequences.

Within many regional, national and

European projects, Arpa Piemonte carried

out many experiences in fields of assessing

methodology for landslides hazard assessment:

for instance, the IMIRILAND Project within Fifth

Framework Programme, Interreg PROVIALP

Project Fall or national Project of Geological

Cartography for shallow and planar landslides

hazard maps in the southern hilly part of Piemonte

region called Langhe (fig. 2).

2) Atlas of Landslides. It is an inventory, in

which polygons and points are divided in 3

classes (fig. 1):

• Fa-Area with Active Landslides (“very

high hazard”). No new buildings or

infrastructures are allowed. Only measures

of protection and reduction of vulnerability;

• Fq-Area with Quiescent Landslides (“high

hazard”). Some enlargements are allowed.

New buildings are allowed according to

city development plan.

• Fs-Area with Stabilized Landslides

(“medium-moderate hazard”). The

development of these areas is indicated in

the city development plan.

The catastrophic event of May 1998, which caused

heavy damages and victims in municipalities

of Sarno and Quindici (Campania), urged the

1) Atlas of Hydro-geological Risks (landslides,

floods, alluvial fans, avalanches) at the

municipal level. Every municipality is valued

on the basis of the hazard, vulnerability

and expected damage. Landslide hazard is

function of ratio between area of landslides

within municipal boundaries and whole area

of municipality.

It has 4 qualitative classes:

• R1-moderate risk. Social damages and few

economic losses are possible.

• R2-medium risk. Few damages to buildings

and infrastructures without loss of

functionality.

• R3-high risk. Problems to human safety.

Many damages and economic losses.

• R4-very high risk. Deaths and severe

injuries are possible.

Fig. 1: Example of Atlas of Landslides published by Po River Basin Authority (elaboration by Arpa Piemonte).

Abb. 1: Beispiel des „Atlas of Landslides“ (Bergsturz-Atlas), veröffentlicht von Po River Basin Authority (Ausarbeitung von ARPA Piemonte).

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existing landslides (fig. 3). Every region decided

by itself if the results of IFFI Project (danger maps)

do or do not have or a legal value. Currently, in

Piemonte landslides inventory coming from IFFI

Project is not a legal basis but it is one of the tools

available that can be consulted.

In any event, IFFI represents a very

important tool for the planners who finally have

the first homogeneous, shared, detailed and most

complete knowledge of the landslide occurrence

on the whole territory.

As a general remark for Italy, it has

to be observed that public legislation defines

general principles and lines of conduct, functions,

activities and authorities involved, while the

regional administrations apply restrictions on land

use through different regional laws.

Final remarks

• Laws or rules that indicate how a landslide

analysis (danger, hazard, risk) has to be

done, do not exist;

• There is often some confusion among

danger, hazard and risk. An inventory

map can be used as hazard map (i.e.

susceptibility map), without any prevision

of scenarios;

• There is some lack of trust in quantitative

methods. Qualitative approach seems to be

preferred;

The technicians who make the maps have to

think firstly:

• Who will be the end users?

• What will be the use of maps?

• Is the scale of work suitable for this?

• Are the complexity of methods (time,

resources, needed input data…) and

results appropriate and understandable for

decision makers?

Anschrift des Verfassers / Author’s address:

Stefano Campus

Arpa Piemonte

Dipartimento Tematico Geologia e Dissesto

via Pio VII 9, 10135 TORINO (ITALY)

stefano.campus@regione.piemonte.it

Literatur / References:

ARPA PIEMONTE, (2006),Note illustrative della Carta della Pericolosità per Instabilità dei Versanti alla scala 1:50,000 Foglio n. 211 Dego. (S. Campus, F. Forlati & G. Nicolò editors), Apat, Roma. (in Italian);

ARPA PIEMONTE, (2007), Evaluation and prevention of natural risks. (S. Campus, F. Forlati, S. Barbero & S. Bovo editors), Balkema Publisher;

ARPA PIEMONTE, (2008), Interreg IIIa 2000-2006 Alpi Latine Alcotra. Progetto n. 165 PROVIALP-Protezione della Viabilità Alpina. Final Report (in Italian);

ARPA PIEMONTE, (2010), Geographic Information System on-line - http://webgis.arpa.piemonte.it

V.A. (2004), Identification and mitigation of large landslides risks in Europe. The IMIRILAND project. (C. Bonnard, F. Forlati & C. Scavia editors), Balkema Publisher;

Hazard assessment and mapping of mass-movements in the EU

authorities and made locally by the regions. It

is the first try of an inventory based on common

graphical legend and glossary.

In Piemonte, over 35,000 landslides

were recognized by interpreting aerial photos

and field surveys and the Informative System of

Landslides is constantly updated with inclusion of

new landslides or corrections and deepening of

So complete coverage of basic information is

available (lithology, geotechnical geo-database,

landslides inventory, etc…), but only few rigorous

applications of hazard & risk assessment.

One of the available tools produced

by Arpa Piemonte is the regional part of Italian

Landslides Inventory (IFFI). It is a national program

of landslide inventory, sponsored by national

Fig. 3: Arpa Piemonte Web-GIS Information Service of the IFFI Project.

Abb. 3: ARPA Piemonte, Web-GIS Informationsdienst des IFFI-Projekts.

Fig. 2: Extract from the shallow landslides hazard map of 1:50,000 scale sheet Dego in Piemonte. The traffic light colors indicate increasing hazard (from green to red), referring to return periods of critical rainfall (Arpa Piemonte, 2006).

Abb. 2: Auszug aus dem Gefahrenzonenplan rutsch-gefährdeter, oberflächen-naher Hänge im Maßstab von 1:50.000 Dego im Piemont. Die Ampelfarben veranschaulichen die zunehmende Gefahr (von grün zu rot) mit Bezug auf Wiederkehrdauern kriti-schen Niederschlags (ARPA Piemonte, 2006).

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but they can be mitigated or avoided, applying

adequate legislation measures supported by

corresponding expert argumentation. Although

Slovenian legislation (and hence also measures)

mainly focuses on the remediation phase and

mitigation of consequences of SMM events that

have already occurred, it’s biggest deficiency lays

in the area of prevention measures. While, in the

case of rare SMM events, the current approach of

exclusively post-event measures is conditionally

sustainable, in the case of frequent events it

1. Introduction

Slovenian territory occupies the Eastern flank of

the Alpine chain. As in other areas of the Alpine

region, Slovenia is exposed to different slope mass

movements (SMM) above the average of the rest of

Europe. SMM that represent substantial problems

can be generally divided into three groups, 1)

landslides, 2) debris-flows, and 3) rock falls. The

majority of SMM events cannot be prevented,

Fig 1: Relation between hazards on one side and elements at risk on the other, and the risk in between (after Alexander, 2002).

Abb. 1: Beziehung zwischen Gefahren und gefährdeten Elementen, und das dazwischen liegende Risiko (nach Alexander, 2002).

Zusammenfassung:Slowenien liegt in einem komplexen Raum Adria – Dinaren – Pannonisches Becken, und seine allgemeine geologische Struktur ist bestens bekannt. Aufgrund seiner außerordentlich heterogenen geologischen Lage ist Slowenien Hangmassenbewegungen (SMM = slope mass movement) sehr stark ausgesetzt. Die slowenische Gesetzgebung (und darauf beruhend auch die entsprechenden Maßnahmen) sind vorwiegend auf die Schadenbehebungsphase und die Begrenzung der Auswirkungen bereits aufgetretener SMM-Vorkommnisse ausgerichtet, es man-gelt jedoch an vorbeugenden Maßnahmen. Der Zweck dieses Artikels ist die Präsentation von Gefahrenhinweiskarten über Hangmassenbewegungen auf nationaler und regionaler Ebene, die zum Schutz vor schnellen Massenbewegungen in Slowenien erstellt wurden und die eine fachlich fundierte Grundlage für die entsprechenden Präventivmaßnahmen bilden. Der nächste logische Schritt wäre, dieses Know-how und diese Ansätze in die Gesetzgebung zu integrieren.Schlüsselwörter: Massenbewegungen, Gesetzgebung, Gefahrenhinweiskarte, Slowenien

Standards and Methods of Hazard Assessment for Rapid Mass Movements in Slovenia

Standards und Methoden der Gefährdungsanalyse für schnelle Massenbewegungen in Slowenien

MARKO KOMAC, MATEJA JEMEC

Summary:Slovenia is situated on the complex Adria – Dinaridic – Pannonian structural junction and its general geological structure is well known. As a consequence of an extraordinarily heterogeneous geological setting, Slovenia is highly exposed to slope mass-movement processes. While Slovenian legislation (and based on that also measures) mainly focuses on the remediation phase and mitigation of consequences of SMM events that have already occurred, its biggest deficiency lays in the area of prevention measures. The purpose of this paper is to represent slope mass movement susceptibility maps on a national and a local level that have been developed for protection from rapid mass movements in Slovenia and which form an expert foundation for the prevention measures. The next logical step would be to incorporate this knowledge and approach into legislation.Keywords: mass movement processes, legislation, susceptibility map, Slovenia

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Water Act (Official Gazette RS, no. 67/02, 4/09)

Protection against the harmful effects of water

that is among other the issues dealt with this

act also refers to protection against landslides.

Threatened area is defined by Government, which

is responsible for protecting the population,

property and land in dangerous exposed areas.

In order to protect against the harmful effects of

water, land in the threatened area is categorized

into classes based on the risk.

Act on measures to eliminate the consequences of certain

large-scale landslides in 2000 and 2001 (Official Gazette

RS, no. 21/02, 92/03, 98/05)

Act defines the format and the method of

financing and form of allocating state aid for

the implementation of remedial measures, to

prevent the spread of landslide and stabilization

of landslides on the specific area of influence. It

covers several major landslides in Slovenia.

Spatial Development Strategy of Slovenia (Official Gazette

of RS, no. 76/04)

The Spatial Development Strategy of Slovenia is a

public document guiding development in the field

of landslide problematics. It provides a framework

for spatial development throughout the country

and sets guidelines for development in European

space. It provides for the creation of spatial

planning, its use and conservation. The spatial

strategy takes into account social, economic and

environmental factors of spatial development.

Slovenia's Development Strategy

Slovenia's Development Strategy sets out the

vision and objectives of Slovenia and five

development priorities with action plans. The

chapter on protection against natural disasters is

included in the fifth development priority, which

is designed to achieve sustainable development.

Regulation of the spatial order of Slovenia (Official Gazette

of RS, no. 122/04)

Regulation of spatial order in Slovenia provides

the rules for managing the field of landslide

problematic. One of the important articles is

Article 67, in which is mentioned how to plan

according to the limitations which are caused by

natural disasters and water protection.

Resolution of the National Environmental Act (Official

Gazette of RS, no. 2/06)

The National Environmental Action Programme

(NEAP) is the basic strategic document in the

field of environmental protection, aimed at

improving the overall environment and quality

of life and protection of natural resources. NEAP

was prepared under the Environmental Protection

Act and complies with the European Community

Environment Programme, which addresses the

key environmental objectives and priorities

that require leadership from the community.

The objectives and measures are defined in

the four areas, namely: climate change, nature

and biodiversity, quality of life, and waste and

industrial pollution.

3. Methodology

Due to specifics of different slope mass movement

processes, a single approach would be hampered

in its results / prognosis. The following chapter

presents an overview of approaches to slope

mass movements (1 – landslides; 2 – debris-flows;

3 – rock falls) hazard assessment. The presented

approaches are similar to a certain level, they also

differ according to the scale of the assessment. The

Hazard assessment and mapping of mass-movements in the EU

Law on protection against natural and other disasters

(Official Gazette of RS, no. 64/94)

The Act governs the protection against natural

and other disasters and includes the protection of

people, animals, property, cultural heritage and

environment against any hazard or accidents (risk)

that can threaten their safety. The main goal of

the protection against natural and other disasters

system is to reduce the number of disasters, and

to forestall or reduce the number of victims and

other consequences of disaster. The basic tasks

of the system are: prevention, preparedness,

and protection against threats, rescue and help,

providing of basic conditions for life, and recovery.

National program of protection against natural and other

disasters (Official Gazette of RS, no. 44/02)

On the basis of the Resolution, the National

Programme of Protection against Natural and

Other Disasters for the period 2002 – 2007.

The National Programme is oriented towards

the prevention and its basic aim is to reduce the

number of accidents and to prevent or minimise

its consequences.

Law on the Remediation of consequences of natural

disasters (Official Gazette of RS, no. 114/05)

The Act defines a landslide as a natural disaster.

According to the article 11, with some restriction

and at some level of damage, state budget funds

may be used to ease the effects of natural disasters.

Damage assessment is made in accordance

with the Regulation on the methodology for

damage assessment (Official Gazette of RS,

no. 67/03, 79/04), after which the landslide is

considered a landslide, which threats a property

or infrastructure.

becomes unsustainable and brings a huge burden

to the local, regional and state budget. The only

reasonable approach would hence be minimising

interaction between SMM events and elements

at risk. Graphically this interaction would be

presented as a cross-section between the natural

hazard on one side and vulnerability of elements

at risk on other side (Fig 1).

2. Legislation in the field of slope mass movement

domain

In the area of systematic prevention measures

regarding SMM, Slovenia lags behind other Alpine

countries or regions. One of the basic approaches

to solve the problem is to establish potentially

hazardous areas due to natural phenomena and

the inclusion of this information in spatial plans.

Information on geology, upon which the slope

mass movement occurrence heavily depends, it is

not yet an integral part of spatial plans. Legislative

acts deal mostly with remediation issues instead

with the prevention measures.

The protection strategy against landslides

(within legislation the term landslide also other

types of slope mass movements are included)

varies substantially and is tailored according

to different terrain conditions. They are mainly

divided into prevention, emergency protective

measures and permanent measures adopted in the

process for remediation. In the frame of preventive

actions, the emphasis is on creating a national

database of active landslides (and other SMM) and

intentions of government to include hazards doe

to landslides into spatial planning. In the planning

and implementation of emergency protective

measures, the emphasis is on protecting human

lives and property.

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The debris-flow susceptibility model for Slovenia

at scale 1:250,000 was also developed at

Geological Survey of Slovenia in 2009 (Komac et

al., 2009). The final result of this approach was

presented in a form of a warning map (Fig. 3).

For the area of Slovenia (20,000 km2), a debris-

flow susceptibility model at scale 1:250,000 was

produced. To calculate the susceptibility to debris-

flow, occurrences using GIS several information

layers were used such as geology (lithology and

distance from structural elements), intensive

rainfall (48-hour rainfall intensity), derivates of

digital elevation model (slope, curvature, energy

potential related to elevation), hydraulic network

(distance to surface waters, energy potential of

streams), and locations of sixteen known debris

flows, which were used for the debris-flow

susceptibility models’ evaluation. A linear model-

weighted sum approach was selected on the

basis of easily acquired spatio-temporal factors to

simplify the approach and to make the approach

easily transferable to other regions. Based on the

calculations of 672 linear models with different

weight combinations for used spatio-temporal

factors and based on results of their success to

predict debris-flow susceptible areas, the best

factors’ weight combination was selected. To avoid

over-fitting of the prediction model, an average of

weights from the first hundred models was chosen

as an ideal combination of factor weights. For

this model an error interval was also calculated.

A debris-flow susceptibility model at scale

1:250,000 represent a basis for spatial prediction

of the debris-flow triggering and transport areas. It

also gives a general overview of susceptible areas

in Slovenia and gives guidance for more detailed

Fig. 2: Landslide susceptibility warning map of Slovenia at scale 1:250,000 (Komac & Ribičič, 2006, 2008).

Abb. 2: Gefahrenhinweiskarte für Rutschungen in Slowenien im Maßstab von 1:250.000 (Komac & Ribičič, 2006, 2008).

GIS in raster format with a 25 × 25 m pixel size.

Five groups of lithological units were defined,

ranging from small to high landslide susceptibility.

Furthermore, critical slopes for the landslide

occurrence, other terrain properties and land cover

types that are more susceptible to landsliding were

also defined. Among triggering factors, critical

rainfall and peak ground acceleration quantities

were defined. These results were later used as

a basis for the development of the weighted

linear susceptibility model where several models

with various factor weights variations based on

previous research were developed. The rest of

the landslide population (35 %) was used for the

model validation. The results showed that relevant

precondition spatio-temporal factors for landslide

occurrence are (with their weight in linear model):

lithology (0.3), slope inclination (0.25), land cover

type (0.25), slope curvature (0.1), distance to

structural elements (0.05), and slope aspect (0.05).

Beside landslide susceptibility

assessment, a rainfall influence on landslide

occurrence was analysed since rainfall plays

an important role in the landslide triggering

processes. Analyses of landslide occurrences in

the area of Slovenia have shown that areas where

intensive rainstorms occur (maximal daily rainfall

for a 100-year period), and where the geo-logical

settings are favourable an abundance of landslide

can be expected. This clearly indicates the spatial

and temporal dependence of landslide occurrence

upon the intensive rainfall. Regarding the landslide

occurrence, the intensity of maximal daily and

average annual rainfall for the 30 years period

was analysed. Results have shown that daily

rainfall intensity, which significantly influences the

triggering of landslides, ranges from 100 to 150

mm, most probably above 130 mm. Despite the

vague influence, if any at all, of the average annual

rainfall, the threshold above which significant

number of landslides occurs is 1000 mm.

final results (but not the only ones) of approaches

presented in the following text were presented

in a form of warning maps that are still the main

product used by end users. All the analyses were

conducted in GIS, which enables the end users to

implement results also in a form of databases or a

digital format.

According to Skaberne (2001) the

terminology of slope mass movements in Slovenia

are as follows: landslides are processes of

translational or rotational movement of rock or

soil as a consequence of gravity at discontinuity

plane(s). Rock falls are processes of falling or

tumbling of a part of rock or soil along a steep

slope. Debris-flows are processes of transportation

of material composed of soil, water and air.

The landslide susceptibility model for

Slovenia at scale 1:250,000 was developed

at the Geological Survey of Slovenia in 2006

(Komac & Ribičič, 2006). The final result of this

approach was presented in a form of a warning

map (Fig. 2). Based on the extensive landslide

database that was compiled and standardised

at the national level, and analyses of landslide

spatial occurrence, a Landslide susceptibility map

of Slovenia at scale 1 : 250,000 was completed.

Altogether more than 6,600 landslides were

included in the national database, of which

roughly half are on known locations. Of 3,257

landslides with known locations, random but

representative 65% were selected and used for

the univariate statistical analyses (χ2) to analyse

the landslide occurrence in relation to the

spatio-temporal precondition factors (lithology,

slope inclination, slope curvature, slope aspect,

distance to geological boundaries, distance to

structural elements, distance to surface waters,

flow length, and land cover type) and in relation

to the triggering factors (maximum 24-h rainfall,

average annual rainfall intensity, and peak ground

acceleration). The analyses were conducted using

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development that included relevant influence

factors. For analytical purposes, 10,816 models

were developed: 3,142 for landslide susceptibility

and 7,674 for rock-fall susceptibility. In both

cases, geology/lithology and slope angle showed

to be the most important influencing factors.

Regarding landslides, additional important factors

were land use and synchronism of strata bedding

and slope aspect, and in the case of rock-falls an

additional important factor was synchronism of

strata bedding and slope aspect.

The methodology is focused towards

the direct use of the final product in the process

of spatial planning at the municipal level and is

divided into four phases as shown in Fig. 4:

• (1) Synthesis of archive geological data

in the overview geohazard map at scale

1:25,000 (Budkovič, 2002).

• (2) Development of statistical geohazard at

scale 1:25,000 (Komac, 2005).

• (3) Development of detailed geohazard

map at scale 1:25,000 as a combination of

synthesis geological map (1) and statistical

geological model (2) and delineating the

most problematic areas.

• (4) Mapping of problematic areas at scale

1:5,000 or 1:10,000 for the purpose of the

highest detail planning.

All presented approaches are based on a probability

statistical model that is a part of a conceptual

development model of general or detailed slope

mass susceptibility maps represented in Fig 5.

Fig. 4: Schematic diagram of the process of production of landslide and rock-fall susceptibility at the municipal scale (1:25.000) (Bavec et al., 2005).

Abb. 4: Schematische Darstellung der Erstellung von Gefahrenhinweiskarten über Erdrutsch, Berg- und Felssturz im Maßstab einer Wanderkarte (1:25.000) (Bavec et al., 2005).

(4) Mapping of problematic areas at scale1:5000 or 1:10,000 for the purpose of the

highest detail planning

(1) Synthesis of archive geological data into theoverview geohazard map at scale 1:25,000

(2) Development of statistical geohazard at scale 1:25,000

(3) Development of detailedgeohazard map at scale 1:25,000 as

a combination of synthesis ofphases (1) and (2)

processes, taking the Bovec municipality as

the case study area. The geohazard map at the

scale 1:25,000 as the final product is aimed

to be directly applicable in spatial planning

of local communities (municipalities). The

requirements that were followed to achieve this

aim were: expert correctness, reasonable time of

elaboration, and easy to read product. Elaboration

of the final product comprises four consecutive

phases, of which the first three are done in the

office: 1) synthesis of archive data, 2) probabilistic

model of geohazard induced by mass movement

processes, 3) compilation of phases 1 and 2 into

the final map at scale 1:25,000. As the last phase,

field reconnaissance of most hazardous areas is

foreseen. The susceptibility model development

was based on the upgrading of the expert geohazard

map at scale 1:25,000 with a probabilistic model

research areas and further spatial and numerical

analyses. The results showed that approximately

4% of Slovenia’s area is extremely high susceptible

and approximately 11% of Slovenia’s area of

susceptibility to debris-flows is high. As expected,

these areas are related to mountainous terrain in

the NW and N of Slovenia.

In the frame of a research project, slope

mass movement geohazard estimation – The

Bovec municipality case study an approach to

assess the landslide and rock-fall susceptibility at

the municipal scale (1:25,000) (Bavec et al, 2005;

Komac, 2005). The production of a susceptibility

map that should represent (officially not included

among the documentation yet) one of basic layers

in the spatial planning process shown in the Fig. 4.

Methodology was developed for estimation

of geohazard induced by mass movement

Fig. 3: Debris-flow susceptibility warning map of Slovenia at scale 1:250,000 (Komac et al., 2009).

Abb. 3: Muren-Gefahrenhinweiskarte Sloweniens im Maßstab von 1:250.000 (Komac et al., 2009).

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Anschrift der Verfasser / Authors’ addresses:

Marko Komac

Dimiceva ulica 14

1000 Ljubljana

SI-Slovenia

Marko.komac@geo-zs.si

Mateja Jemec

Dimiceva ulica 14

1000 Ljubljana

SI-Slovenia

Mateja.jemec@geo-zs.si

Literatur / References:

ALEXANDER, D.E., 2002. Principles of emergency planning and management. Oxford University Press, New York, 340 pp.

BAVEC, M., BUDKOVIČ, T. AND KOMAC, M., 2005. Estimation of geohazard induced by mass movement processes. The Bovec municipality case study. Geologija, 48/2, 303-310.

BUDKOVIČ, T., 2002. Geo-hazard map of the municipality of Bovec. Ujma, 16, 141-145.KOMAC, M. 2005. Probabilistic model of slope mass movement susceptibility - a case study of Bovec municipality, Slovenia. Geologija, 48/2, 311-340.

KOMAC, M., RIBIČIČ, M., 2006. Landslide susceptibility map of Slovenia at scale 1:250,000. Geologija, 49/2, 295-309.

KOMAC, M., KUMELJ, Š. AND RIBIČIČ, M., 2009. Debris-flow susceptibility model of Slovenia at scale 1: 250,000. Geologija, 52/1, 87-104.

SKABERNE, D., 2001. Prispevek k slovenskemu izrazoslovju za pobočna premikanja. Ujma, 14–15, 454–458.

Hazard assessment and mapping of mass-movements in the EU

or discreet variable value. Final slope mass

movements susceptibility values (the range

is between 0 and 1) were classified into 6

susceptibility classes: 0 – Negligible (or None); 1

– Insignificant (or Very Low); 2 – Low; 3 – Medium

(or Moderate); 4 – High; 5 – Very High.

4. Conclusion

Slope mass movement processes are specific in

their nature, hence separate analyses had to be

performed and a different model development

had to be developed. In Slovenia, slope mass

movement susceptibility maps have been

developed on national and on local level. In the

case of the latter, which has an actual application,

value maps were developed only for some test

areas. Thus several questions remain open and

these are: when will the geohazard layer be

included as a compulsory part of the spatial

planning document, to what extent quality

geological data will be used for the assessment,

and how the lack of detailed geological data

would be tackled.

For all influence factors included in the weighted

sum model calculation, original values were

transformed into the same scale, which ranged

from 0 – 1 to assure the equality of the input data.

In other words, within each factor original values

were normalised with the eq. 1.

eq. 1

Where NVR represents new and normalised

value, and RV the old (nominal) value. Min and

Max represent the minimum and maximum

original value within the factor, respectfully. For

the purpose of the development of the best and

at the same time the most logical susceptibility

model, a weighted sum approach (Voogd, 1983)

was used (eq. 2).

eq. 2.

Where H represents standardised relative

phenomenon susceptibility (0 – 1), wj represents

the factor weight, and fij represents a continuous

Fig 5: Concep-tual model of development of general or detailed slope mass susceptibil-ity maps.

Abb. 5: Konzeptionelles Modell für die Entwicklung von allgemeinen oder detaillierten Gefahrenhin-weiskarten über Hangbewegun-gen.Development of

phenomenonsusceptibility map

Testing of differentmodels developed on

the weighted sumof influence factors

Selection of optimal and most logical

susceptibility model

Univariate analysis (x2)of SMM occurrence byclasses within each of

the influence factor

Influence factors classesranging based upon

their influence on the SMM occurrence

Values normalisationwithin each influence

factor (0-1)

Field testing

Bad results

Good results

(RV - Min)NVR = , Max - Min

H = ∑ wj x fij j=l

n

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• Main data of the topic mass movements and

subrosion / karst with information about the

spatial positioning, about determination of

coordinates, etc.

• Commonly shared technical data of the

subject mass movements and subrosion /

karst with information about the date

of origin, about the land use and about

damage, etc.

• Specific technical data of the subject mass

movement and subrosion / karst

• Data concerning subsidence and uplift

Computerized modelling increasingly allows

the identification of hazard areas that have been

verified using the landslide inventory or through

evaluation of the results of field work. The

current emphasis in Germany is on hydrological

modelling of flood events that are used for

water management issues in flood prevention.

Geotechnical modelling is used increasingly for

rock falls, avalanches and shallow landslides.

1. Introduction

In Germany, geogenic natural hazards, such

as mass movements, karstification, large scale

flooding as well as ground subsidence and uplift

affecting building ground, shall be recorded,

assessed and spatially represented using a common

minimal standard in the future. For this purpose,

the “Geohazards” team of engineering geologists

of the different German federal governmental

departments of geology (SGD) are giving

recommendations on how to create a hazard map.

These recommendations of minimum requirements

are directed at the employees of the SGD. An

important component for developing hazard maps

is the construction and evaluation of landslide

inventories (e.g. landslide or sinkhole inventories).

The recorded data in the inventories

should have a minimal nationwide standard and

are divided into:

Hazard assessment and mapping of mass-movements in the EU

Zusammenfassung:Informationen über geogene Gefährdungen (z.B. Steinschlag, Felsstürze, Rutschungen) sind als GEORISK-Daten über das Bodeninformationssystem Bayern (BIS-BY) im Internet oder Intranet abrufbar (www.bis.bayern.de). Dieses Informationssystem wird bereits von vielen Fachstellen genutzt. Neben den Landkreisen sowie vielen Kommunen sind die Behörden der Wasserwirtschaft, der Straßen- und Forstverwaltung sowie private Planer die Hauptnutzer. Im BIS-BY ist bisher allerdings nur das Herkunftsgebiet von Gefährdungen dargestellt, nicht der planungsrelevante Gefährdungsbereich. Dieser kann nur durch empirische oder numerische Simulationen und Modellierungen abgegrenzt werden. Die Gefahrenhinweiskarte gibt eine Übersicht über die Gefährdungssituation. Sie basiert sowohl auf Modellrechnungen als auch auf empirischen Untersuchungen und wird mit dem GEORISK-Ereigniskataster (BIS-BY) auf Plausibilität geprüft. Bezüglich der räumlichen Ab-grenzung kann sie Ungenauigkeiten enthalten und die Gefährdung nicht in jedem Fall genau wiedergeben. Die Gefahrenhinweiskarte hält für große Gebiete flächendeckend fest, wo mit welchen Gefahren gerechnet werden muss. Daraus lassen sich mit geringem Aufwand mögliche Konfliktstellen zwischen Gefahr und Nutzung ableiten. Die Gefahrenhinweiskarten können einerseits in Flächennutzungspläne mit einfließen und dienen anderseits zur Prioritä-tensetzung beim Erarbeiten weitergehender Maßnahmen.

Standards and Methods of Hazard Assessment for Geological Dangers (Mass Movements) in Bavaria

Standards und Methoden zur Verminderung von geologischen Gefährdungen durch Massenbewegungen in Bayern

KARL MAYER, ANDREAS VON POSCHINGER

Summary:Information about geological hazards in the Bavarian Alps (e.g. rock falls, landslides) is available in the Internet or intranet section Georisk of the Bodeninformationssystem Bayern (BIS-BY) (www.bis.bayern.de). This information system is already used by a number of departments such as district administrations, water and traffic management offices, forest management as well as private users. By now the BIS-BY only shows the sites of origin of geological hazards and not the whole endangered area, which would be relevant for land use planning. This area, the so called process area, can only be defined by empirical or numerical simulations and models.A hazard map gives an overview of the situation. It is based on model calculations and empirical analysis and can be verified by the Georisk-cadastre (BIS-BY). Concerning the spatial extent of the process areas, possible inaccuracies may impair an exact expression of the danger. The hazard map shows large areas where a special type of danger can be assumed. Therefore, will be easier to deduce possible conflicts between hazards and land use. Hazard maps can be included in the land development plan or can be used to assign priorities while taking measures.

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3.2 Basis data for landslide modelling

Information about geological hazards such as

landslides, rock falls and earth falls, especially

in the densely populated areas in the Bavarian

Alps, is available in the section Georisk of

the Bodeninformationssystem Bayern (BIS-BY,

www.bis.bayern.de), a GIS-based inventory of

Bavaria including numerous geological data. By

now (October 2010), about 4,500 landslide events

have been detected and evaluated within the

project area. Every event is described concerning

its process type and dimension, the age and

potential future trend of the landslide as well as

annotations about the source and the degree of

information. Origin and accumulation zones of

landslides have been digitised and stored as well

as significant photos. With all of this the BIS-BY is

the most important source of information.

Also integrated in the BIS-BY are maps

of active areas that have been mapped by field

work, aerial photo analysis and archive data for

the main settlement areas. Within these maps

landslides are classified into four levels of activity

to give an indirect statement about the level of

danger. These maps can be used to estimate the

extension of deep-seated landslides, for example.

Above all, results of two other projects

have been used: Within the project HANG

(historical analysis of alpine hazards), historical

data of landslides have been evaluated and

digitised. Within the project EGAR (catchment

areas in alpine regions), the risk potential of

alpine torrents has been estimated analysing the

discharge and catchment potential.

4. Fall processes

4.1 Minimum requirements in Germany

In many states of Germany, only medium to long

term, large-scale numeric modelling of rock

fall hazards are possible using high resolution

terrain models and specialised software. In the

first stage, a “black and white map” is created

showing verified / potential rock fall areas derived

from the landslide inventories and / or remote

sensing (DEM). This map shows verified as well

as potential rock fall escarpments i.e. slopes with

an inclination > 45° (in Alpine areas). The entire

process area is, however, not depicted.

In the second stage, the run-out zone, i.e.

the entire process area, is depicted. That means

areas prone to rock falls due to the inclination, but

which are not confirmed. To define these areas,

estimated empiric angle methods or physical

deterministic models can be used.

To determine rock fall escarpments, the

shadow angle and the geometric slope angle is

applied. Both the shadow angle (e.g. 27°) as well

as the geometric slope angle (e.g. 32°) can be

used as the estimated angle (Mayer & Poschinger

2005). An angle of deflection from the vertical

slope can be used as a lateral boundary of the

process area (e.g. 30°).

In Bavaria this method is used for

huge rock masses. For single blocks, a physical

trajectory model from Zinggeler + GEOTEST is

used (MAYER 2010).

4.2 Modelling rock fall of single blocks (methods use in

Bavaria)

For the detection of potential starting zones of

rock falls, two empirical approaches can be

applied. In a first step, potential starting zones

2. Definition of a hazard map

The federal geological surveys of Germany

agreed on definitions for the terminology used

for mapping of geological hazards (Personenkreis

“Geogefahren” 2008) based on BUWAL (2005). A

hazard map gives a first overview of areas affected

by landslides (potentially endangered area) and

can be a basis for the detection of conflicts of

interests. By defining a most probable design

event and integrating it in the landslide modelling

process, a hazard map also gives a qualitative

statement about the probability of a landslide

event. The potential process areas of the expected

landslides vary depending on the design event,

the geological, topographical and morphological

situation and the existence of forest. Modelling

parameters for rock fall and shallow landslide

simulations can be deduced and trivialised from

comprehensive data.

Generally the scale of a hazard map

ranges from 1:10,000 to 1:50,000. Within this

project, despite the possibilities of the zoom

function of a GIS, the hazard map is produced for

a scale of 1:25,000.

3. Material and methods

3.1 Basis maps

Essential data basis for modelling the hazard map

is a high resolution digital elevation model (DEM)

derived from airborne laser scanning. The datasets

are used in different resolutions (1 m, 5 m, 10 m)

depending on the modelling approach. The

vertical resolution is better +/- 0.3 m, except for

very few areas where currently no laser scanning

data is available.

If necessary, in addition to the tools described

above, field studies will be needed for exact

clarification and assessment of given situations.

In Alpine regions, natural hazards are

a common phenomenon. Landslides, rock falls

and mudflows occur in the course of mountain

degradation that reflects the natural slope

instability of mountain areas. Landslides are mostly

triggered by extreme rainfall that will, according

to climate scientists, become more relevant in

Alpine regions in particular (Umweltbundesamt

2008). With an increase in heavy rainfall events

an increase in landslide events must be expected.

With approximately 4450 km², the

Bavarian Alps cover about 6.3 % of Bavaria. The

Bavarian Alps are the most important tourist region

of Bavaria and, therefore, of particular importance.

Furthermore, they have a unique ecological value

that has to be specially protected. Since it is more

and more difficult to ensure this protection by

structural activities, protective measures need

to be involved in the planning process and also

allow sustainable and cost effective strategies.

The most effective and sustainable

method to prevent losses arising from hazardous

events is to avoid land use in the endangered

areas. In areas where construction already has

been established or where construction of new

infrastructure or buildings is unavoidable, it

is essential to determine areas endangered by

geological hazards.

In May 2008, the Bavarian Environmental

Agency launched the project hazard map for the

Bavarian Alps. The aim of the project is to create

a hazard map for deep seated landslides, shallow

landslides and rock fall areas for the whole of

the Bavarian Alps. It will be finished during

December 2011.

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4.3 Modelling rock fall masses (Bavarian approach)

The trajectory model for rock fall (chapter 4.2)

calculates the reach of single blocks. For the run-

out zone of larger rock fall volumes, an empirical

process model with a worst case approach is used.

Numerous papers (Lied 1977, Onofri & Canadian

1979, Evans & Hungr 1993, Wieczorek et al. 1999,

Meißl 1998) show that a global angle method is an

appropriate approach to determine the maximum

run-out zone of rock fall. Two different global

angles have been applied. The first and more

important one is the shadow angle (β in Fig. 3). It is

defined as angle between the horizontal line and

the connecting line from the block with maximum

run out and the top of the talus. According to

Evans & Hungr (1993) a shadow angle of 27°

has been assumed. The other global angle is the

geometrical slope angle that spans between the

horizontal line and top of detachment zone (α in

Fig. 3). A minimum geometrical slope angle of 30°

is presumed (Meißl 1998).

The application of the different global

angles depends on slope morphology. A proper

decision for one global angle model can be

reached by the quotient of shadow angle tangent

and geometrical slope tangent. If the quotient is

below 0.88, the shadow angle has to be used.

Otherwise the geometrical slope angle is better

suited to describe the maximum run-out zone

(Mayer & von Poschinger 2005).

Global angles can easily be modelled

with implemented functionalities of standard

GIS programs. Within the project, the viewshed

function of Spatial Analyst in ArcGIS has been

employed. This function identifies all cells on

a surface (DEM) that can be seen from selected

observation points (Fig. 4). There are a number

of important attributes of every starting point

necessary for the modelling process: the vertical

view angle, which is the predefined global angle

(Fig. 3), the horizontal view angle that is defined

with 30°, as well as the aspect that can be

calculated out of the DEM.

Fig. 3: Global angle models: shadow angle (β) and geometrical slope angle (α) (Meißl 1998, modified).

Abb. 3: Pauschalgefällemodelle: Schattenwinkel (β) und Geometrisches Gefälle (α), verändert nach Meißl (1998).

by field work. As a result, a mean block size and

geometry that represents the most probable event

has been determined for every geological unit.

This design event has been assigned to one of

four volume classes. For each of these classes the

mean block mass has been calculated. The block

mass of a geological unit is an input parameter for

the simulation.

The simulation of the block movement

is carried out according to physical principles of

mechanics and is separated into falling, bouncing

and rolling (Fig. 1). The calculation is a succession

of these processes with intermediate contacts to

underground and tree trunks.

The loss of energy during tread mat

is controlled by deformability and surface

roughness. These parameters have to be deduced

and trivialised from the basis data of the area to be

investigated.

The simulation has been run for two

different scenarios. Within the first scenario, the

forest with the protecting function of the trees

has been considered. To simulate a worst-case

scenario, the forest has not been included in the

second scenario.

stored in the BIS-BY are extracted. These starting

zones are detected by field work. In areas where

no information is available, an even more empiric

approach must be applied: it has to be assumed

that every slope steeper than 45° is a potential

detachment zone (Wadge et al. 1993).

According to Meißl (1998) or Hegg &

Kienholz (1995) the process model can be divided

into two parts: the trajectory model calculating

the paths of the blocks as vectors and the friction

model calculating the energy along these paths

as well as the run-out length. In this project, the

vector based simulation model of Zinggeler &

GEOTEST (Krummenacher et al. 2005) is used.

Beside the topographical information derived from

the DEM, damping and friction characteristics of

the slope surface and the vegetation have to be

known. Furthermore it is very important to define

a design event for rock fall. That means that,

according to the geology, form and dimension of

typical blocks have to be determined.

As the block dimension is the only

variable parameter within the simulation, it plays

an essential role in the calculation of the run- out

zone. To assess the design events, the starting zones

already determined within the disposition model

have been intersected with the geological map.

The affected geological units have been checked

Fig. 1: Basic processes during rock fall simulation (Krum-menacher et al. 2005).

Abb. 1: Schematische Darstellung der prinzipiellen Prozesse der Steinschlagmodellierung (Krummenacher et al. 2005).

Fig. 2: 3D Trajectories with (red) and without (orange) the protecting function of forest.

Abb. 2: 3D Sturztrajektorien mit (rot) und ohne (orange) Berücksichtigung der Schutzfunktion des Waldbestandes.

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demonstrated that deep-seated landslides mostly

occur in areas already affected by landslides

in the past. For this reason they can be used as

design events. To detect these areas, information

about known landslides, extracted from the

databases listed in chapter 3.2 has to be evaluated.

Permanent activity or more or less recurrent

reactivation likely produces enlargement of the

landslide area identified in the disposition model,

both the detachment and run-out zone upward

and downward.

Since a numeric modelling of deep seated

landslides is not available for a regional scale, the

determination of the potential process area has

to be worked out with empirical methods, taking

into account the local geology and morphology.

Under extreme conditions, the process

area can reach the next ridge, terrace or depression

in the greater surroundings of the landslide. In the

case of small-scaled scars in smooth slopes, a margin

of 20 – 30 m has been added to the detachment

areas to assess the potential process area.

To determine the potential run out of an

active or reactivable landslide, the present run-

out length has been determined by databases,

hillshades and field work in a first step. If there are

indications for active movements in the landslide

toe, it is assumed that the run-out length will

proceed even further in case of a reactivation. The

danger area has to be dimensioned according to

geomorphologic conditions.

6. Flow processes

6.1. General approach

The procedure and depiction of flow processes

like deep-seated landslides (Talzuschub) is similar

to the method used for slide processes. Flow

processes rarely occur in low mountain ranges.

In the German Alpine area, debris flows are

more related to water-related hazards and for this

reason not explained here in detail.

The deep-seated landslides are handled

in the same way as the slide processes. The

process occurring in the run-out zone of shallow

landslides is also mostly a flow process. To estimate

this process as disposition model in Bavaria, the

physical computer model SLIDISP is used. To find

the run-out zones and to simulate the process, the

model SLIDEPOT (GEOTEST) is applied.

6.2 Modelling shallow landslides (methods used in Bavaria)

Shallow landslides are usually triggered by heavy

rainfall, depending on the predisposition of the

slope. Like the rock fall simulation, the modelling

of shallow landslides is carried out in two steps.

The starting zones are calculated in the disposition

model and the run-out zones are calculated in the

process model.

For the disposition model, the

deterministic numerical model SLIDISP (Liener

2000 and GEOTEST AG) is used. This assumes an

above average precipitation for a certain area. The

Infinite-Slope-Analysis is applied to calculate the

slope stability for every raster cell. Fundamental

basic data are the slope angle, derived from the DEM

from which the thickness of soil will be deduced

and the geology which allows to determine friction

angle and cohesion as geotechnical parameters.

The factor of safety F will be calculated for every

raster cell to describe the ratio of retentive and

impulsive forces (Fig. 5, Selby 1993).

The natural range in the variation of

different input parameters will be considered

using a Monte-Carlo-Simulation. For every

raster cell, the number of instable cases will be

determined. The higher the number of instabilities

the higher is the probability of slope failure.

Since the occurrence of forest affects the stability

in an enormous way, the root strength will be

In the second stage, potential

landslide areas are determined in addition to

the verified landslide areas. That means areas

prone to landslides due to the geological and

morphological situation and the land use (were

landslides have not yet taken place). These areas

can be found by using empirical methods due to

the geological and morphological circumstances

and the land usage; alternatively / additionally:

Visualisation of semi-automatically derived areas

(cross-over between DEM / geological entity); e.g.

using an additional signature

The distinction between shallow and

deep-seated slides is optional when visualising

the hazard map. Near-surface landslides of

a small volume (shallow slides) are either

separately determined using above procedure or

are displayed simultaneously alongside the deep-

seated slides.

5.2 Modelling deep seated landslides

(methods used in Bavaria)

Deep-seated landslides are mostly result of the

activation of predefined failure zones, i.e. by

long lasting rainfall. Experience shows that they

can range from about 5 m up to more than 100

m in depth. To identify areas endangered by deep

seated landslides, two different approaches have

been applied. On the one hand, areas showing

evidence of previous deep-seated landslides, with

either ongoing activity or a clear probability of

reactivation, have been evaluated. On the other

hand, the terrain has been evaluated concerning

an increased susceptibility for deep-seated

landslides.

The locality of the origin of danger (areas

showing a higher probability for the development

of a deep seated landslide) has been identified

within the previously cited disposition model.

Previous experiences and analysis have

To identify of hazard areas, only important rock

fall areas with evidence of activity have been

processed. Due to long-lasting field work, there

is an excellent overview of the situation within

the densely populated areas in the Bavarian Alps.

Beyond those areas it is assumed that all important

rock fall areas are known. To start the modelling

process, first the global angle approach has to be

chosen (shadow angle or geometrical angle). After

digitizing the starting points and determination of

necessary attributes, the viewshed modelling with

ArcGIS can be executed.

5. Slide processes

5.1 Minimum requirements in Germany

In the first stage, landslide inventories, e.g. all

registered objects and the associated near-surface

processes, should be visually displayed. That

means affected by definite indications of active

and inactive landslides and landslides that have

already occurred (reactivation or enlargement of

the landslide area is possible). The areas can be

found using mapping (registers) or remote sensing

(DEM) methods.

Fig. 4: The viewshed function identifies all raster locations to be seen from appointed starting points with defined global angle.

Abb. 4: Die Viewshed-Funktion ermittelt alle Bereiche, die von festgelegten Startpunkten mit einem definierten Vertikal- und Horizontalwinkel gesehen werden.

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Verified karstification features from the

Geological map, event register or remote sensing

(e.g. DEM) methods. In the first stage, superficial

or near-surface subrosion features (e.g. sinkholes,

depressions, clefts) are visualised. There is

no differentiation between fossil and current

subrosion features. The second stage includes

the visualisation of the dispersion of karstifiable

sediments. Hazard fields can be derived using

a point or area statistical evaluation (e.g. using

the feature density or a raster based density

calculation), as well as using influencing factors,

such as geology, tectonics and hydrogeology.

The result of the second stage determines

the differentiation of hazard areas. Where

applicable, the hazard areas can be coupled

with general geotechnical recommendations as

to construction work in karst landscapes. Special

conditions in individual states, e.g. mining

influences on karstification, can be noted in an

additional category. Optionally, a differentiation

between carbonate, sulphate and chloride

karstification can be implemented in the first or

second stage of the hazard map. If the information

is available in individual states, the spread of the

inner and outer salt slopes as well as intact salt

domes should be entered into the hazard map.

8. Discussion

The hazard map has been worked out for a regional

scale (1:25,000). Therefore the boundaries of the

hazard areas are not sharply bounded lines and

a detailed view on particular areas or objects is

not allowed. In addition, the modelling of the

different processes can make no claim to be

complete. The maps show potentially endangered

areas that have been determined on the basis of

available information and that has been computed

with modern numerical models. Anthropogenic

preventive measures have not been introduced

into the models.

Improbable and extreme events have not

been considered. Instead, frequently occurring

events have been modelled since they are more

representative and felt more as a risk. From a

geological view, rare and extreme events have

to be accounted as an unavoidable residual and

remaining risk.

The hazard maps for rock fall of single

blocks and rock fall masses and deep-seated

landslides are based on field work for the most

part. On the contrary, the hazard areas of shallow

landslides are solely based on computer models

and represent a typical susceptibility map.

Therefore, they are presented as hatched areas.

In the field, witnesses of former traces of shallow

landslides are hard to find due to weathering.

However, if the predicted consequences of

Fig. 6: Calculation of accumulation: for the central cell with exposition of 210° –230°, the 20° sector identifies 3 cells that are either starting zones or already show accumulation (orange cells).

Abb. 6: Berechnung der Auslaufbereiche: Für die Rasterzelle in der Mitte mit der Zellexposition 210°–230° wurden drei Rasterzellen im Sektor von 20° ermittelt, die sowohl Anbruchzone als auch Auslaufbereich sind (orange Raster-zellen).angle. The expansion stops if a defined number

of expansion steps is achieved or if the calculated

value falls below a defined threshold.

The run-out zones will be calculated for

both scenarios. In both cases, a maximum of 8

expansion steps have been calculated while the

degradation factor has been reduced in the forest.

Because of uncertainties concerning complex

edge conditions, the degradation factors have

been defined quite pessimistically. With this the

run-out zones are large enough and rather too

large in the case of doubt.

7. Subrosion / karstification

Superficial or near-surface subrosion features

(sinkholes) and the knowledge of subrodable

sediments serve as criteria for the analysis of

a process area. In the first stage, the following

hazard areas are distinguished:

integrated in the calculation of the factor of safety

as an additional parameter. Considering the root

strength and its effect on soil stability it is possible

to simulate two scenarios with different intensities

of the “root effect” (high and low).

To calculate the run-out zones. the

raster-based model SLIDEPOT is used (GEOTEST

AG). For every raster cell in the starting zone,

the accumulation will be modelled in the flow

direction. The model is based on neighbourhood

statistics. Above a potential accumulation cell, the

raster cells inside a 20° sector will be analysed

(Fig. 6). Accumulation will be calculated if there

is a starting zone and if the topography in the

sector named above is not convex. Every step of

expansion will analyse the neighbourhood up to a

defined distance (4 cells; red circle in Fig. 6). With

every step, the hypothetical starting volume and

the rest volume will be reduced by a degradation

factor, which depends foremost on the slope

Fig. 5: Principle for the calculation of the factor of safety F for every raster cell (Selby 1993).

Abb. 5: Grundlagen zur Berechnung des Sicherheitsgrades F einer Rasterzelle (Selby 1993).

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KIENHOLZ, H., ERISMANN, TH., FIEBIGER, G. & MANI, P. (1993): Naturgefahren: Prozesse, Kartographische Darstellung und Maßnahmen. – In: Tagungsbericht zum 48. Deutschen Geographentag in Basel, 293 – 312, Stuttgart.

KRUMMENACHER, B., PFEIFER, R., TOBLER, D., KEUSEN, H. R., LINIGER, M. & ZINGGELER, A. (2005): Modellierung von Stein- und Blockschlag; Berechnung der Trajektorien auf Profilen und im 3-D Raum unter Berücksichtigung von Waldbestand und Hindernissen. – anlässlich Fan-Forum ETH Zürich am 18.02.2005, 9 p., Zollikofen.

LIED, K. (1977): Rockfall problems in Norway. – In: Istituto Sperimentale Modelli e Strutture (ISMES), 90: 51-53, Bergamo.

LIENER, S., (2000): Zur Feststofflieferung in Wildbächen. Geographisches Institut Universität Bern. Geographica Bernensia G64, Bern.

MAYER, K. & VON POSCHINGER, A. VON (2005): Final Report and Guidelines: Mitigation of Hydro-Geological Risk in Alpine Catchments, “CatchRisk”. Work Package 2: Landslide hazard assessment (Rockfall modelling). Program Interreg IIIb – Alpine Space.

MAYER, K., PATULA, S., KRAPP, M., LEPPIG, B., THOM, P., POSCHINGER, A. VON (2010): Danger Map for the Bavarian Alps. Z. dt. Ges. Geowiss., 161/2, p. 119-128, 10 figs. Stuttgart, June 2010

MEISSL, G. (1998): Modellierung der Reichweite von Felsstürzen. – In: Innsbrucker Geographische Studien, 28: 249 p., Innsbruck (Selbstverl. des Instituts für Geographie der Universität Innsbruck).

ONOFRI, R. & CANDIAN, C. (1979): Indagine sui limiti di massima invasione dei blocchi franati durante il sisma del Friuli del 1976. – Regione Autonoma Friuli-Venezia Giulia e Università degli Studi di Trieste, 41 p., Trieste (Cluet Publisher).

PERSONENKREIS “GEOGEFAHREN“ (2008): Geogene Naturgefahren in Deutschland – Empfehlungen der Staatlichen Geologischen Dienste (SGD) zur Erstellung von Gefahrenhinweiskarten; not published.

SELBY, M.J. (1993): Hillslope Materials and Processes, Oxford University Press, Oxford.

UMWELTBUNDESAMT [eds.] (2008): Klimaauswirkungen und Anpassung in Deutschland – Phase 1: Erstellung regionaler Klimaszenarien für Deutschland. – http://www.umweltdaten.de/publikationen/fpdf-l/3513.pdf

WADGE, G., WISLOCKI, A.P. & PEARSON, E.J. (1993): Spatial analysis in GIS for natural hazard assessment. In: Goodchild, M.F., Parks B.O. & Steyaert, L.T. (Hrsg.) – Environmental modelling with GIS: 332-338, New York, Oxford.

WIECZOREK, F. G., MORRISSEY, M. M., IOVINE, G. & GODT, J. (1999): Rockfall Potential in the Yosemite Valley, California. – In: U.S. Geological Survey Open-File Report 99-0578, http://pubs.usgs.gov/of/1999/ofr-99-0578/.

To help potential users interpret the

hazard map, the results are presented to all

authorities. Furthermore, an intensive cooperation

with the Bavarian Environment Agency is offered.

In addition, a limited version of the hazard map is

published on the Internet (www.bis.bayern.de).

But the Alpine part of Bavaria is not the

only region affected by geological hazards. The

Alpine foothills and the Swabian-Franconian

Jurassic-mountains are affected as well. For the

mid-term, the goal is to develop hazard maps for

the whole of Bavaria.

Anschrift der Verfasser / Authors’ addresses:

Karl Mayer

Bavarian Environment Agency (LfU)

(Office Munich)

Lazarettstraße 67

80636 Munich – GERMANY

Andreas von Poschinger

Bavarian Environment Agency (LfU)

(Office Munich)

Lazarettstraße 67

80636 Munich – GERMANY

Literatur / References:

BUNDESAMT FÜR RAUMENTWICKLUNG, BUNDESAMT FÜR WASSER UND GEOLOGIE, BUNDESAMT FÜR UMWELT, WALD UND LANDSCHAFT (BUWAL) [eds.] (2005): Empfehlungen Raumplanung und Naturgefahren. – 50 p., Bern.

EVANS, S. G. & HUNGR, O. (1993): The assessment of rock fall hazards at the base of talus slopes. – Canadian Geotechnical Journal, 30 (4): 620-636, Ottawa (Nat. Res. Council of Canada).

HEGG, C. & KIENHOLZ, H. (1995): Deterministic paths of gravity-driven slope processes: The „Vector Tree Model“. In: Carrara, A. & Guzzetti, F. (eds.): Geographical Information Systems in Assessing Natural Hazards, 79 – 92, Dordrecht.

climate change with an increase in extreme

rainfalls will come true, an increasing number of

shallow landslides must be taken into account.

Climate change predictions could be

implemented in the model if maps with predicted

precipitation on a local scale were available.

This would allow the identification of hot spots

with heavy rainfall and, therefore, a higher

susceptibility for landslides. The identification of

such hot spots is one target in the Alpine Space

Programme project AdaptAlp that also focuses

on evaluation, harmonizing and improvement of

different methods for hazard mapping.

9. Conclusions

A hazard map is a very helpful tool for planning

authorities to get an overview about land use

conflicts and potentially endangered areas. It is

a general map created under objective scientific

criteria and indicating geological hazards that

have been identified and localized but not

analysed and evaluated in detail. A hazard map

does not contain specifications about the degree

of hazard or the intensity or probability of an

event.

The map will be provided to local and

regional planning authorities for water, traffic,

and forest management. It helps the planner

identify hot spots and make decisions concerning

measures of protection. On the other hand, it also

shows areas not endangered and free for planning.

In critical cases, the hazard map has

to disclose the requirement for further analysis.

In this cases a detailed expertise analysis has

to decide if measures are technically feasible,

economically reasonable and under sustainable

aspects really necessary.

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of territorial coherence at an inter-urban scale and

local urban planning at the community scale.

Typically, urban planning procedures

and decisions, under the jurisdiction of national or

local authorities, must integrate natural hazards.

The plan for prevention of natural hazards (plan de

prévention des risques naturels prévisibles - PPR)

established by the law of February 2, 1995, is now

one of the national authority’s main instruments

for preventing natural hazards. The PPR is a

specific procedure designed to take into account

natural hazards in land-use development.

The PPR is elaborated under the authority

of the department’s prefect, which approves it

after formal consultation with municipalities and

a public inquiry. The PPR involves the local and

regional authorities concerned from the very first

steps of its preparation (Fig. 1). It can cover one

or several types of hazards and one or several

municipalities.

Introduction

Hazard assessment of rapid mass movements

is required for different purposes than for other

natural phenomena. Depending on the objectives,

this must be carried out at different scales. Hazard

assessment can also take different forms, but

most often its final outcome is a hazard map.

Different types of expertise from various experts

and approaches contribute to hazard assessment.

Therefore, establishing standardized approaches,

methods and tools is demanding. The field of land-

use planning, however, integrates standardized

hazard assessment and mapping methods.

Hazards mapping and land-use planning

Natural hazards must be taken into account in land-

use planning documents. These are mainly schemes

Hazard assessment and mapping of mass-movements in the EU

dung im Rahmen der Flächennutzungsplanung standardisiert: Der Plan für die Verhinderung von Naturgefahren (plan de prévention des risques naturels prévisibles, PPR) ist eines der wichtigsten Mittel der französischen nationalen Behörden für die Vermeidung natürlicher Gefahren und findet in der Flächennutzungsplanung Berücksichtigung. Im Rahmen dieses Verfahrens beschreiben allgemeine methodologische Richtlinien und andere, für die verschiedenen Arten von Gefahren spezifische Dokumente die Bedin-gungen und geben Aufschluss über die empfohlenen Methoden und Ansätze zum Erstellen des PPR. Eines dieser Dokumente befasst sich mit den durch Massenbewegungen verur-sachten Gefahren. In diesem Verfahren ist der Gefahrenzonenplan ein Zwischenschritt in der Erstellung des Risikoplans, d.h., die Vorgaben stammen vom PPR (gemeinsam mit den zugehörigen Bestimmungen). Für die Erstellung von Gefährdungsanalysen und die Gefahrenzonenplanung (Ge-fahrenkartierung) stehen – beruhend auf einem Bestand von Phänomenen und einer Analyse aktueller und vergangener Ereignisse – verschiedene Arten von Informationen und Datenban-ken zur Verfügung. Gefährdungsanalysen müssen eine gegebene Gefahr in Bezug auf die Intensität und Häufigkeit des Auftretens beschreiben. Für Massenbewegungen sind spezifische Ansätze empfohlen, welche die spezifischen Merkmale dieser Erscheinungen berücksichtigen.

Standards and Methods of Hazard Assessment for Rapid Mass Movements in France

Standards und Methoden der Gefährdungsanalyse für schnelle Massenbewegungen in Frankreich

DIDIER RICHARD

Summary:Hazard assessment is required for different purposes and is carried out through expertise assessments at different levels, using various approaches. Hazard assessment and mapping methods are standardized at least for their use in the frame of land-use planning in what is called the plan for the prevention of natural hazards (plan de prévention des risques naturels prévisibles, PPR). This is one of the main instruments used by the French national authorities for preventing natural hazards while taking them into account in land use development. Within this procedure, a general methodological guidelines document and other documents specific to the different types of hazards specify the conditions and clarify the method and approach proposed to draw up the PPR. One of these documents is dedicated to mass movement hazards. In this procedure, the hazard map is an intermediate step in elaborating the risk map, i.e. the regulations stemming from the PPR (together with the associated regulations). Various types of information available and databases can be used for hazard assessment and hazard mapping, based on an inventory of phenomena and a back-analysis of current and past events. Hazard assessment must characterize a given hazard in terms of intensity and frequency of occurrence. For mass movements, specific approaches are proposed, given the specific characteristics of these phenomena.

Zusammenfassung:Gefahrenbeurteilungen sind für verschiedene Zwecke erforderlich und werden in Form von fachlichen Gutachten auf unterschiedlichen Ebenen anhand verschiedener Ansätze vorge-nommen. Gefährdungsbeurteilung und Kartierungsmethoden sind zumindest für die Verwen-

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craft, commercial or industrial activity, for their

completion, use or exploitation and requirements

of any kind can be used, up to total prohibition.

The PPR may also define general preventive,

protection and safety measures that must be

taken into account by communities as well as

individuals. This option particularly concerns

measures relating to the safety of persons and the

organization of rescue operations as well as all

general measures that are not specifically related

to a particular project.

Finally, the PPR may take an interest

in existing structures as well as new projects.

However, for property construction that has been

allowed in the past, only limited improvements

whose cost is less than 10% of the market or

estimated value of the property can be required.

As a complement to the PPR – the central

tool of the French national authorities’ natural

hazards prevention action – other procedures

and tools are designed to provide preventive

information that must be provided to inhabitants

possibly exposed to hazards (information tools:

DDRM, DCS, DICRIM, IAL, etc.) as well as

measures relating to the safety of persons and the

organization of rescue operations that must be

taken into account by communities and private

individuals (safety measures plan: PCS). These

procedures are mandatory for the municipalities

with an existing PPR. Danger studies are also

mandatory for certain classes of hydraulic works

(new regulations for dams and dikes). Adequate

hazard assessment (and mapping) is of course also

necessary for all these prevention tools.

Rapid mass movements

Approximately 7,000 French municipalities are

threatened by mass movements, one-third of

which can be highly dangerous for the population.

Most of these towns, located in mountain regions,

are exposed to various phenomena stemming

from the instability of slopes and cliffs (collapses,

rock falls, landslides).

Mass movements are demonstrations

of the gravitational movement of ground masses

destabilized under the influence of natural

solicitations (snow melting, abnormally heavy

rainfall, an earthquake, etc.) or human activities

(excavation, vibration, deforestation, exploitation

of materials or groundwater, etc.).

They vary greatly in form, resulting from

the multiplicity of triggering mechanisms (erosion,

dissolution, deformation and collapse under

static or dynamic load), themselves related to the

complexity of the geotechnical behaviour of the

materials (geologic structure, geometry of the

fracture networks, groundwater characteristics, etc.)

According to the velocity of movement, two

groups can be distinguished:

• Slow movements, for which the deformation

is progressive and can be accompanied by

collapse but in principle without sudden

acceleration:

Ground subsidence consecutive

to changes in natural or artificial

subterranean cavities (quarries or mines);

Compaction by shrinkage of clayey

grounds and by consolidation of certain

compressible grounds (muck, peat);

Creep of plastic materials on low slopes;

Landslides, i.e. a mass movement along

a flat, curved or complex discontinuity

surface of cohesive grounds (marls and

clays);

Shrinkage or swelling of certain clayey

materials depending on their moisture

content.

• Rapid movements which can be split into

two groups, according to the propagation

mode of materials:

applied when the safety of persons is involved.

In other cases, this principle remains particularly

warranted by the cost of preventive measures to

reduce the vulnerability of future constructions

and the cost of compensation in cases of

disaster, financed by society. However, since

the prevention objectives are then based on

economic considerations, it is possible to discuss

the limits of prohibitions and requirements with

local actors, elected officials and economic and

consumer representatives without departing from

this principle. Adjustments can be accepted when

the situation does not allow alternatives. For

example in urban centres, where requirements

to reduce the vulnerability of projects and

preventive, protection and safety measures

allowing the organization of emergency services

will be set up.

The PPR may operate in zones that are

directly at risk, but also in other zones that are

not in order to avoid aggravating existing risks

or causing new ones. It regulates projects for

new installations. It may prohibit or impose

requirements on any type of construction,

structure, development or any farming, forestry,

For areas exposed to greater hazards, the PPR is

a document which informs the public on zones

that expose populations and property to hazards.

It regulates land use, taking into account natural

hazards identified in this zone and goals of

nonaggravation of risks. This regulation extends

from authorising construction under certain

conditions to prohibiting construction in cases

where the foreseeable intensity of hazard or the

nonaggravation of existing risks warrants such

action. This guides development choices on less

exposed land in order to reduce harm and damage

to persons and property.

The PPR is designed for urban planning

and is incumbent on everybody: individuals,

companies, communities and government

authorities, especially when delivering building

permits. It must therefore be annexed to

the local urban planning plan when such a

document exists.

The basis for the regulation of projects

in the perimeter of a PPR is to discontinue

development in areas with the greatest hazard

and, therefore, to prohibit land development

and construction. This principle must be strictly

Fig. 1: PPR elaboration scheme (Source: V. Boudières; 2008)

Abb. 1: Programm zur Ausarbeitung eines PPR (Quelle: V. Boudières; 2008)

Hazard assessment and mapping of mass-movements in the EU

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sinking, collapse, rock falls, landslides, and

associated mud flows, but it excludes debris flows

in general.

The general guide, published in August

1997, presents the PPR, specifies how it should

be drawn up and tries to answer the numerous

questions that may arise for their implementation.

The other guidelines, such as the one dedicated

to mass movements, clarify the method and

approach proposed for the various types of risks.

The general methodology establishes that the PPR

is composed of:

• a presentation report explaining the

analysis of the phenomena considered

and the study of their impacts on people

and existing or future property. This report

explains the choices made for prevention,

stating the principles the PPR is based on

and commenting the regulations adopted.

• a regulatory map at a scale generally

between 1:10,000 and 1:5,000, which

delineates areas controlled by the PPR.

These are risk-prone areas but also areas

where development could aggravate the

risks or produce new sources of risk.

• regulations applied to each of these areas.

The regulations define the conditions

required for carrying out projects,

prevention, protection and safety measures

that must be taken by individuals or

communities, but also measures applicable

to existing property and activities.

The regulatory zoning of the PPR is based on

risk assessment, which depends on the analysis

of the natural phenomena that may occur and

of their possible consequences in terms of land

use and public safety. This analysis includes four

preliminary stages:

• Determination of the risk basin and the

study perimeter;

• Knowledge of the historic and active natural

phenomena: inventory and description;

• Hazard qualification: characterization of

natural phenomena which can arise within

the study perimeter;

• Evaluation of the socioeconomic and

human stakes subjected to these hazards.

The elaboration of the PPR generally begins

with the historical analysis of the main natural

phenomena that have affected the studied

territory. This analysis, possibly supplemented

by expert advice on potential hazards, results

Fig. 3: Positioning of the hazard map within the general procedure of PPR elaboration

Abb. 3: Positionierung des Gefahrenzonenplans in der allgemeinen Ausarbeitungs-phase eines PPR

Standards and methods

In France’s administrative and institutional

organization, certain activities and policies remain

the jurisdiction of centralised authorities, such as

the policy for natural risk prevention, overseen by

the Ministry of the Environment. This is probably

one of the most significant differences compared

with other Alpine countries. One consequence

is the willingness to maintain a minimum

homogeneity and coherence at the national level

and in the way different types of natural hazards

are treated.

Within the framework of this common

procedure, a general methodological guidelines

document has been published, followed by others

specific to the different types of hazards: floods,

forest fires, earthquakes, snow avalanches (to be

approved), torrential floods (to be approved)…

One of these guideline documents is dedicated

to geological hazards, including subsidence,

The first group includes:

Subsidence resulting from the sudden

collapse of the top of natural or artificial

subterranean cavities, without damping

by the surface layers;

Rock falls resulting from the mechanical

alteration of fractured cliffs or rocky

scarps (volumes ranging from 1 dm3 to

104 or 105 m3);

Some rock slides.

The second group includes:

Debris flows, which result from the

transport of materials or viscous or fluid

mixtures in the bed of mountain streams;

Mud flows, which generally result from

the evolution of landslide fronts. Their

propagation mode is intermediate between

mass movement and fluid or viscous

transport.

Fig. 2: The PPR methodological guidelines col-lection

Abb. 2: Die Sammlung me-thodologischer Richtlinien für einen PPR

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Fig. 5: Geological maps and databases (www.brgm.fr)

Abb. 5: Geolo-gische Karten und Datenban-ken (www.brgm.fr)

Fig. 6: Example of a ZERMOS map

Abb. 6: Beispiel eines ZERMOS-Plans

Hazard assessment and mapping of mass-movements in the EU

and field surveys. Priority must be given to these

elements, as stipulated by article 3 of the decree

of October 5th, 1995, which specifies that the

elaboration of PPR takes into account the current

state of knowledge.

The main information sources are:

• Municipal archives (technical documents,

deliberations, miscellaneous documents,

petitions, general reports or accident

reports, etc.);

• Parochial archives;

• Departmental sources (archive and quarry

services, miscellaneous diagnoses, etc.);

• Engineering consulting firm documents

(geotechnical and geological reports, civil

engineering studies and reports, field visit

reports, etc.);

• General and research documents (scientific

papers, geological guides, monographs,

PhD theses, etc.);

• Field surveys and eye witness accounts;

• Existing databases and maps, aerial

photographs.

Historical and existing studies as well as field

investigations are collected for the study of the

in a hazard map that evaluates the scope of

predictable phenomena. This map, including an

analysis of the territory outcomes carried out in

consultation with the various local partners, is

the basis for reflection during the elaboration

of the PPR. Combining the levels of hazard and

outcomes allows defining risk zones.

Therefore, in this procedure the hazard

map is an intermediate step necessary to elaborate

the risk map, i.e. the real regulatory outcome of

the PPR (together with the associated regulations).

The study of phenomena by risk basin produces

the hazard map, which is combined with the

identification of elements at risk in drawing up the

risk map.

Data and information

The first step in elaborating hazard maps consists

of collecting all available data and information

that can be exploited for hazard assessment.

Priority is given to the qualitative general studies

and to the back-analysis of past events. The

general studies are conducted based on existing

data, the back-analysis of past or current events

Fig. 4: The first step of hazard mapping

Abb. 4: Der erste Schritt der Gefah-renzonen-planung

Available maps and data bases

Study of phenomenaby risk basin

Historical and existing studies, field investigation

Informative map ofnatural phenomena Elements at risk

appreciationRisk Prevention

Plan (PPR)

Risk management

Annexation asservitude in the PLU

Hazard map

Necessary information and consultation

Identification of elements at risk

Regulatorydocuments

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implement. Different classes of intensity can

be identified if these measures remain within

the domain of an individual owner or a group

of owners or if they require community

intervention and investment (Fig. 8).

Geological hazard qualification is based on

qualitative criteria, such as the observed or expected

damage or impacts or the cost range of possible

countermeasures for the intensity evaluation.

The frequency of events is estimated on

the basis of the historical events identified on

the site. The reference hazard is the most severe

potential events considered by the expert as likely

to occur in a 100-year period (or more frequently

if human lives are concerned), or the most severe

historical event identified on an equivalent site.

The probabilistic approach based on

a frequency analysis is possible only for some

phenomena such as rock falls. This assumes that

sufficient data are available, which is actually

rare. As most mass movements are not repetitive

processes, contrary to earthquakes or floods, it is

necessary to consider a probability of occurrence

of an event qualitatively over a given period (e.g.

50 or 100 years), without reference to numerical

values. For instance, three levels or probabilities

may be used: low, medium and high.

In most cases, the occurrence probability is not

a true probability, but is simply a scale of relative

susceptibility, relying on elements such as slope

angle, lithology, fracturing of the rock mass,

presence of water, etc.

The hazard is graded by combining the

time occurrence and the intensity, typically in a

2D table (Fig. 10). There is no general specification

for this stage of the hazard evaluation, but

presenting the key of the hazard evaluation is

strongly recommended.

In the presence of substantial human

and socioeconomic danger, methods and

tools specifying the spatial extension of the

phenomena, thus reducing uncertainty, can be

used: run-out modelling for rock falls, geophysics

surveys delineating underground mines, etc. In

case of rock falls and related phenomena, hazard

evaluation includes both the stability analysis

of rock masses and run-out distance evaluation.

Numerical tools are increasingly used to estimate

the maximal run-out distance, but the reliability of

the results is highly dependent on the experience

of the engineering geologist.

Generally, the topographic basis used is

the IGN (National Geographic Institute) 1:25,000

map, enlarged to 1:10,000. In presence of

Fig. 8: Example of relationships proposed between the importance of countermeasures and intensity level

Abb. 8: Beispiel der empfohlenen Beziehungen zwischen der Bedeutung der Gegenmaßnahmen und der Intensitätsstufe

Intensity level Coutermeasures importance level

Low Can be financed by an individual owner

Medium Can be financed by a limited group of owners

HighConcerns a spatial area larger than the individualownership scale and/or very higth cost and/or technically difficult

Major No possible technical countermeasureOnly a few cases in France (Séchilienne, la Clapière...)

it is difficult to directly translate their physical

characteristics in terms of intensity, except by

defining as many hazards as movement types,

which would make the hazard zoning document

difficult to read. It is therefore necessary to refer to

more global criteria so they can be compared and

their use for regulatory zoning facilitated.

Different methods are possible to assess a

representative intensity level for all phenomena:

• As for earthquakes, intensity can be

translated in terms of potential for damage,

using parameters such as the volume of

soil or rock involved, the depth of the

failure surface, the final displacement,

the kinetic energy, etc. However, damage

potential depends not only on the physical

phenomenon, but also on the vulnerability

of buildings, which introduces a bias.

• Intensity can be assessed according to

the importance and the cost of protection

measures that would be necessary to

phenomena step. Maps and databases are available

for this work: geological maps at a 1:50,000 scale,

covering France (Fig. 5 - www.brgm.fr); a few

Zermos maps (Fig. 6) of zones exposed to soil

movement hazards, a combination of susceptibility

levels and geomorphologic features, which are

quite old and not exhaustive; a French database

of mass movements (Fig. 7 - www.bdmvt.net);

and an events database of the RTM services that

will soon be on line.

Hazard assessment

Hazard evaluation includes three components:

the intensity of mass movements, the time of

occurrence and the spatial extension. Once

translated into regulatory zoning, the information

contained in this map will be used to manage and

plan land development and construction works.

Hazards are thus qualified in terms of intensity.

Considering the variety of mass movements,

Fig. 7: The BDMVT, French database of mass movements (www.bdmvt.net)

Abb. 7: BDMVT – franzö-sische Da-tenbank für Massenbe-wegungen (www.bdmvt.net)

Hazard assessment and mapping of mass-movements in the EU

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Conclusion

Methods assessing hazards for rapid mass

movements are still mostly empirical and rely

on the experience of the engineering geologist.

The PPR guidelines give a general framework

and general principles for hazard assessment and

mapping. Precise rules are not yet available at the

national level. The geological analysis remains the

basis of hazard evaluation, but numerical tools as

GIS and computer simulation are also used. The

main requirement is that the method used should

be explained.

Anschrift des Verfassers / Author’s address:

Didier Richard

Cemagref – Unité de Recherche

“érosion torrentielle, neige et avalanches”

BP 76 – F 38402 Saint-Martin-d’Hères Cedex

Tel. : +33 4 76 76 27 73

mail : didier.richard@cemagref.fr

Acknowledgements

Jean-Louis Durville, Conseil général de

l'environnement et du développement durable.

Alison Evans, Service de Restauration des Terrains

en Montagne de Haute-Savoie.

The person to contact for more information on this

policy within the French Ministry of Sustainable-

development, is François Hédou (Francois.

HEDOU@developpement-durable.gouv.fr).

Literatur / References:

RISK PREVENTION FRENCH WEBPORTAL: www.prim.net

RISK MAPPING: http://cartorisque.prim.net/

WEBSITE OF THE FRENCH MINISTRY IN CHARGE OF RISK PREVENTION POLICY: http://www.developpement-durable.gouv.fr/

FRENCH MASS MOVEMENTS DATABASE: http://www.bdmvt.net/

BRGM (bureau de recherches géologiques et minières) Website: http://www.brgm.fr/

LCPC (1999) L'utilisation de la photo-interprétation dans l'établissement des plans de prévention des risques liés aux mouvements de terrain. Collection Environnement, 128 p.

LCPC (2000) Caractérisation et cartographie de l'aléa dû aux mouvements de terrain. Collection Environnement, 91 p.

MINISTÈRE DE L'AMÉNAGEMENT DU TERRITOIRE (1999). Plans de prévention des risques naturels (PPR). Risques de mouvements de terrain. La Documentation française, 71 p.

Hazard assessment and mapping of mass-movements in the EU

or Séchilienne (Isère), involving more than 10

million cubic metres of material, ad hoc methods

of hazard assessment have been set up, including

the monitoring of movement and various

computer simulations.

substantial damage potential or if the precision

of the study and the amount of available data

allow it, it is possible to map the hazards on a

1:5,000-scale map.

As far as very large mass movements are

concerned, such as La Clapière (Alpes-Maritimes)

Fig. 9: Decision process for assessing the reference hazard

Abb. 9: Entscheidungsprozess zur Bewertung der Bezugsgefährdung

Abb. 10: Beispiel für die Erstellung einer Übersichtstabelle über Steinschlaggefahr (von CETE du sud-ouest)

Fig 10: Example of hazard table determination for rock fall hazard (from CETE du sud-ouest)

Intensity level

Probability of occurrence

LowDetermining factors

identified on the site are diffuse, poorly deter-

mined.

MediumMany determining factors are identified on the site. Some factors unlisted can appear

with time.

HighSome nonidentified de-termining factors on the site. The intensity of the

factors is high.

LowRock Falls < 1 dm3

Very low to low hazard Very low to low hazard /

MediumRock Falls < 100 m3

Very low to low hazard Medium hazard High hazard

HighCollapses > 100 m3 / High hazard High hazard

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Geological Hazard Prevention Map of Catalonia

1:25,000 (MPRGC25M)

The most important mapping plan is the Geological

Hazard Prevention Map of Catalonia 1:25,000

(MPRGC25M). This project started in 2007. The

MPRGC includes the representation of evidence,

phenomena, susceptibility and natural hazards

of geological processes. These are the processes

generated by external geodynamics (such as slope,

torrent, snow, coastal and flood dynamics) and

internal (seismic) geodynamics. The information

is displayed by different maps on each published

sheet. The main map is presented on a scale of

1:25,000, and includes landslide, avalanche and

flood hazard. The hazard level is qualitatively

classified as high (red), medium (orange) and low

(yellow). The methods used to analyze hazards

basically consist of geomorphological, spatial and

statistical analysis.

Several complementary maps on a

1:100,000 scale show hazards caused individually

by different phenomena in order to facilitate the

Introduction

With Law 19/2005, the Parliament of Catalonia

approved the creation of the Geological Institute

of Catalonia (IGC) assigned to the Ministry of

Land Planning and Public Infrastructures (DPTOP)

of the Catalonian Government.

One of the functions of the IGC is to

“study and assess geological hazards, including

avalanches, to propose measures to develop

hazard forecast, prevention and mitigation and

to give support to other agencies competent in

land and urban planning, and in emergency

management”. Therefore, the IGC is in charge of

making official hazard maps for such a finality.

These maps comply with the Catalan Urban Law

(1/2005) which indicates that building is not

allowed in those places where a risk exists.

The high density of urban development

and infrastructures in Catalonia requires

geo-thematic information for planning. As

a component of the Geoworks of the IGC,

the strategic programme aimed at acquiring,

elaborating, integrating and disseminating the

basic geological, pedological and geothematic

information concerning the whole of the territory

in scales suitable for land and urban planning.

Geo-hazard mapping is an essential part of this

information. Despite some tests carried out with

wide land recovery (Mountain Regions Hazard

Map 1:50,000 [DGPAT, 1985], Risk Prevention

Map of Catalonia 1:50,000 [ICC, 2003]), at

present the work is done mainly on two scales:

land planning scale (1:25,000), and urban

planning scale (1:5,000 or more detailed). These

scales imply different approaches and methods to

obtain hazard parameters used for such a purpose.

The maps are generated in the framework of a

mapping plan or as the final product of a specific

hazard report. These different types of hazard

mapping products are explained below.

Fig. 1: First published sheet, Vilamitjana (65-23), in 2010.

Abb. 1: Das erste veröffentlichte Blatt, Vilamitjana (65-23), 2010.

Hazard assessment and mapping of mass-movements in the EU

Geohazards Mapping in Catalonia

Kartierung von geologischen Gefahren in Katalonien

Summary:This paper presents the different lines of work being undertaken by the Geological Institute of Catalonia (IGC) on geological hazard mapping. It describes the different map series, scales of representation, methodologies and its expected use.

Keywords: hazard mapping, geohazards, Catalonia.

Zusammenfassung:Diese Abhandlung bietet einen Überblick über die verschiedenen Aktivitäten des Geologi-schen Instituts Katalonien (IGC) für die Kartierung geologischer Gefahren. Sie beschreibt die unterschiedlichen Kartenserien, den Umfang der Darstellungen, die angewandte Methodik und den erwarteten Gebrauch der Karten.

Schlüsselwörter: Gefahrenkartierung, Geogefahren, Katalonien.

PERE OLLER, MARTA GONZÁLEZ, JORDI PINYOL, JORDI MARTURIÀ, PERE MARTÍNEZ

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equate the parameters that define them. The

same frequency/activity values were used for all

phenomena, but magnitude values were adapted

to each of them.

Each hazard level contains some

considerations for prevention (Fig. 3). These

considerations inform about the need for further

detailed studies and advise about the use of

corrective measures.

Hazard from each phenomena is

analyzed individually. The main challenge of the

map is to easily present the overlapping hazard of

different phenomena. A methodology identifying

that this overlap exists has been established

with this objective in mind. It indicates what the

maximum overlapped hazard is (Fig. 4), but in any

case, without obtaining new hazard values.

An epigraph is assigned, to identify the hazard

level and the phenomena that causes it, especially

in overlapping areas (Fig. 5). This epigraph

consists of two characters, the first in capital

letters, indicates the value of hazard (A for high

hazard, M for medium hazard and B for low

hazard), and the second, in lower-case, indicates

the type of phenomena (e for large landslides, s

for landslides, d for rockfalls, x for flows, a for

avalanches and f for subsidence and collapses).

The higher the overlapping is, the longer the

epigraph will be.

Fig. 3: Prevention recommendations.

Abb. 3: Empfohlene Präventivmaßnahmen.

Fig. 4: Multi-hazard representation.

Abb. 4: Darstellung von Mehrfachrisiken.

Fig. 5: Example of multi-hazard representation.

Abb. 5: Beispiel von Mehrfachrisiken.

Fig. 6: Main map 1:25000, which includes landslides, ava-lanches, sinking and flooding according to geomorphologic criteria.

Abb. 6: Hauptkarte 1:25000; sie veranschaulicht die Gefahren hinsichtlich Bergstürze, Lawinen, Absenkung und Hochwas-ser nach geomorphologischen Kriterien.

Hazard assessment and mapping of mass-movements in the EU

4. Population inquiries: the goal of this stage is to

complement the information obtained in the

earlier stages, especially in aspects such as the

intensity and frequency. It is done through a

survey to witnesses who live and/or work in the

study areas.

In a second step, areas susceptible to be

affected by the phenomena are identified from the

starting zone to the maximum extent determinable

at the scale of work. Their limits are drawn taking

into account the catalogue of phenomena,

geomorphological indicators of activity, and from

the identification of favourable lithologies and

morphologies of the terrain. This phase includes

the completion of GIS and statistical analysis

to support the determination of the starting and

run-out zone. It can be extensively applied with

satisfactory results with regard to the scale and

purpose of the work.

Finally, hazard is estimated on the basis

of the analysis of the magnitude and frequency (or

activity) of the observed or potential phenomena.

Susceptibility areas are classified according to

the hazard matrix represented in Fig. 2. Hazard

zones are represented as follows: areas where

no hazard was detected (white), zones with low

hazard (yellow), medium hazard zones (orange),

and areas with high hazard (red).

In order to obtain an equivalent hazard

for each phenomena, an effort was made to

reading of the sheet and understanding of the

mapped phenomena. Two additional maps for

flooding and seismic hazards, represented on

a 1:50,000 scale, are added to the sheet. The

map is to provides government and individuals

with an overview of the territory with respect to

geological hazards, identifying areas where it is

advisable to carry out detailed studies in case of

action planning. At the same time, a database

is being implemented. It will incorporate all the

information obtained from these maps. In the

future it will become the Geological Hazard

Information System of Catalonia (SIRGC).

The procedure followed in the main map consists

of three steps:

1.Catalogue of phenomena and evidences

2.Susceptibility determination

3.Hazard determination

The catalogue of phenomena and evidence is

the base of the further susceptibility and hazard

analysis. It consists of a geomorphologic approach

and it comprises the following phases:

1. Bibliographic and cartographic search: the

information available in archives and databases

is collected.

2. Photointerpretation: carried out on vertical

aerial photos of flights from different years

(1957, 1977, 1985, 2003, etc.). The observation

of the topography and the vegetation allows

the identification of areas with signs of

instability coming from the identification and

characterization of events that occurred recently

or in the past, and from activity indicators.

3. Field survey: checking and contrasting on the

field, the elements identified in the previous

phases. Field analysis allows a better approach

and understanding, and therefore identifying

signs and phenomena are not observable

through the photointerpretation.

Fig. 2: Hazard matrix (based on Altimir et al, 2001).

Abb. 2: Gefahrenmatrix (auf der Grundlage von Altimir et al, 2001).

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Avalanche Paths Map (MZA)

A second mapping plan, already finished, is

the Avalanche Paths Map (MZA). It was begun

in 1996 and finished in 2006. An extent of

5,092 km2 was surveyed. During this process

17,518 avalanche paths were mapped. This is

a susceptibility map on a scale of 1:25,000,

useful for land planning in the Pyrenean areas.

The methodology is based on the French “Carte

de Localisation des Phénomènes d’Avalanches”

(Pietri, 1993). On this map, the avalanche paths,

mapped from terrain analysis (photointerpretation

and field work), are represented in orange, and the

inventory information (witness surveys, historical

documents, field surveys and dendrochronology)

is represented in violet.

The termination of the MZA allows a first global

vision of the avalanche hazard distribution in this

region. The area potentially affected by avalanches

covers 1,257 km2. That is at 3.91% of the Catalan

country, and considering the Pyrenean territory, it

affects 36%.

At present, all the avalanche information

is stored in the avalanche database of Catalonia

(BDAC). New events, coming from avalanche

observation, are added to this database. The

information is available via the Internet at:

http://www.icc.cat/msbdac/.

Hazard maps for urban planning

At present, for all the municipalities that want to

increase their building limits, the procedure is

first of all to make a preliminary hazard map on a

1:5,000 scale. This element is, in fact, just a map

of “yes or no”, which states if a hazard exists or

not. If the municipality decides not to develop in

hazardous areas, the process finishes. In the case

that the municipality wants to build in the hazard-

zone areas, more detailed studies have to be

completed. These studies include complex data

collection, usually via drilling specific boreholes,

other geotechnical work, and advanced modelling.

Fig. 11: Flooding hazard map symbology.

Abb. 11: Symbologie Hochwasser-Gefahrenzonenkarte.

Fig. 12: First published Avalanche Paths Map, “Val d’Aran Nord”, in 1996.

Abb. 12: Erste veröffentlichte Lawinenzugkarte „Val d’Aran Nord“, 1996.

Fig. 10: Flooding hazard map 1:100,000 based on hydraulic modeling.

Abb. 10: Hochwasser-Gefahrenzonenkarte 1:100.000 auf der Grundlage hydraulischer Modellierung.

Hazard assessment and mapping of mass-movements in the EU

The final map (Fig. 8) also represents the values of

the basic seismic acceleration of the compulsory

"Norma de Construcción Sismorresistente

Española" (NCSE-02) for a placement in rock,

and the intensity of the seismic emergency plan

(SISMICAT).

Flooding hazard map

The flooding hazard map at 1:50,000 scale shows

the limits of the hydraulic modeling for periods of

50, 100 and 500 years provided by the Catalan

Water Agency (ACA). A flooding map according to

geomorphologic criteria was done in those streams

were hydraulic modeling was not performed.

Complementary maps

Complementary maps represent the hazard

established for each individual phenomena at

1:100,000 scale. The purpose of these maps is

to facilitate the interpretation of the main map.

Depending on the type of phenomena identified

in the main map, the number of complementary

maps can vary from 1 to 6.

Seismic hazard map

This map was obtained from the map of seismic

areas for a return period of 500 years, for a

middle ground, and considering the effects of soil

amplification.

To take into account the amplification

of the seismic motion due to soft ground, a

geotechnical classification of lithologies from

the Geological Map of Catalonia 1:25,000 into

4 types was carried out: R (hard rock), A (compact

rocks), B (semi-compacted material) and C (non

cohesive material). This classification is based on

the speed of the S-wave through them (Fleta et al.,

1998). The proposed amplifications were assigned

to each group of lithologies. For types R and A no

additions of any degree of intensity were made,

but for types B and C, there was an addition of

0.5 degrees of intensity.

Fig. 7: Complementary map of surface landslide hazard.

Abb. 7: Komplementärkarte über Erdrutschrisiken.

Fig. 8: Seismic hazard map 1:100,000.

Abb. 8: Seismische Gefahrenzonenkarte, 1:100.000.

Fig. 9: Seismic hazard map symbology.

Abb. 9: Symbologie seismische Gefahrenzonenkarte.

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Hazard assessment and mapping of mass-movements in the EU

Anschrift der Verfasser / Authors’ addresses:

Pere Oller, Marta González, Jordi Pinyol,

Jordi Marturià, Pere Martínez

Institut Geològic de Catalunya

C/ Balmes 209/211

08006 Barcelona

Literatur / References:

PIETRI, C., 1993: Rénovation de la carte de localisation probable des avalanches. Revue de Géographie Alpine nº1. P. 85-97.

AGÈNCIA CATALANA DE L’AIGUA (Departament de Medi Ambient i Habitatge). Directrius de planificació i gestió de l’espai fluvial. Guia tècnica. 45 pp.

ALTIMIR, J.; COPONS, R.; AMIGÓ, J.; COROMINAS, J.; TORREBADELLA, J. AND VILAPLANA, J.M. (2001): Zonificació del territori segons el grau de perillositat d’esllavissades al Principat d’Andorra. Actes de les 1es Jornades del CRECIT. 13 I 14 de setembre de 2001. P. 119-132.

FLETA, J., ESTRUCH, I. I GOULA, X. (1998).Geotechnical characterization for the regional assesment of seismic risk in Catalonia. Proceedings 4th Meeting of the Environmental and Engineering Geophysical Society, pàg. 699-702. Barcelona, setembre 1998.

NCSE-02 (2002). Norma de Construcción Sismorresistente Española. Parte General y de Edificación, Comisión Permanente de Normas Sismorresistentes, Real Decreto 997/2002 del 27 de septiembre de 2002, Boletín Oficial del Estado nº 244, viernes 11 de octubre de 2002. Ministerio de Fomento. P. 35898-35987.

The phenomena taken into account are landslides,

rock falls, sinking and snow avalanches. In these

maps, the hazard mapping is obtained from

frequency/intensity analysis. Advanced modelling

analysis is performed in order to obtain the most

accurate results, and to support the observational

data and expert criteria. Up to the present day,

there is no standard methodology. The current

challenge for the IGC is to prepare guidelines for

such a goal in order to guarantee the standards of

quality and homogeneity.

There are preliminary studies of a hazard

mapping plan 1:5,000 for snow avalanches. In

this map terrain is classified into high hazard (red),

medium hazard (blue) and low hazard (yellow).

Urban planning implications regarding hazard

have not been defined yet. An analysis of the MZA,

supported by the statistical α−β model, resulted in

the identification of 24 urban areas to be mapped.

The mapping methodology includes terrain

analysis, avalanche inventory, nivometeorological

analysis and numerical modelling to complete the

information.

Fig. 13: Interface of the avalanche data server

Abb. 13: Benutzeroberfläche des Lawinendatenservers

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planners. This view led to national assessments

of landslides being carried out in the 1980’s and

1990’s on which the current national policy is

largely based. These assessments provided the

basis for planning policies and guidance that, to

some degree, continue to control development

on or around unstable ground. However, limited

resources since this initial push to understand the

problem meant that these initiatives have failed

to develop into an effective, integrated, national

response to deal with landslides in GB. The

current systems, which are neither centralized nor

legally binding, comprise a system of planning

regulations (Town and Country Panning Act

1990), guidance notes, operational regulations

and building codes (Building Regulations, 2006).

With the exception of the Building Regulations,

none of these legal statutes specifically mention

Background on landslide research and planning in

Great Britain

Prior to the 1966 Aberfan disaster, which

led to the deaths of 144 people, landsliding

was not widely considered to be particularly

extensive or problematic in Great Britain (GB).

In the years following the disaster, a limited

amount of research into landslide distribution

and mechanisms was undertaken but failed to

lead to a structured regulatory framework for

managing landslide risk. The Aberfan landslide

and costly disruptions to infrastructure projects

in the 1960/70’s (Skempton & Weeks 1976 and

Early & Skempton 1972) strengthened the view

that the extent of ground instability was neither

well understood nor managed by developers or

Zusammenfassung:Aufgrund einer weniger extremen Topographie und der beschränkten tektonischen Aktivität des Landes unterscheiden sich Auftreten und Verlauf von Erdrutschen in Großbritannien von denen in vielen anderen Ländern der Welt, z.B. Italien und Frankreich. Glaziale Veränderungen der Landschaft während des Pleistozäns, denen schwierige periglaziale Bedingungen folg-ten, haben eine hohe Anzahl von vorzeitlichen oder relikten Bergstürzen verursacht. Die für höhere Entlastungszonen in Europa typischen Muren und Felsstürze treten zwar auf, doch ihre Wahrscheinlichkeit, Entwicklungs- und Bevölkerungszentren zu beschädigen, ist gering. Trotz des häufig geringen Ausmaßes von Erdrutschen in Großbritannien heben zahlreiche bekannte Ereignisse der letzten Jahre nach wie vor die Notwendigkeit hervor, anwendbare Informationen über Rutschungen zu erstellen. Vom British Geological Survey (BGS) wurde eine nationale Ge-fahrenhinweiskarte für Rutschungen entwickelt, anhand derer potentielle Bereiche von Instabi-lität aufgezeigt werden können. Die Erstellung der nationalen Gefahrenhinweiskarte (GeoSure) war auf der Grundlage umfangreicher Datenarchive möglich, die vom BGS zum Beispiel auf der Grundlage der National Landslide Database, der National Geotechnical Database und von digitalen geologischen Karten angelegt wurden. Diese Gefahrenhinweiskarte findet beispiels-weise in der Versicherungsbranche Anwendung und wurde für eine Reihe extern finanzierter Projekte übernommen, die auf bestimmte Probleme abzielen.

SchlüsselwörterBritish Geological Survey, Rutschungen, GeoSure, National Landslide Database

Standards and Methods of Hazard Assessment for Mass Movements in Great Britain

Standards und Methoden der Gefahrenbewertung von Massenbewegungen in Großbritannien

CLAIRE FOSTER, MATTHEW HARRISON, HELEN J. REEVES

Summary:With less extreme topography and limited tectonic activity, Great Britain experiences a different landslide regime than countries in many other parts of the world e.g. Italy and France. Glacial modification of the landscape during the Pleistocene, followed by severe periglacial conditions have led to the presence of high numbers of ancient or relict landslides. Debris flows and rock falls common to higher relief areas of Europe occur but are less likely to interfere with development and population centres. Despite the often subdued nature of landslides in Great Britain, numerous high profile events in recent years have highlighted the continued need to produce useable, applied landslide information. The British Geological Survey has developed a national landslide susceptibility map which can be used to highlight potential areas of instability. It has been possible to create the national susceptibility map (GeoSure) because of the existence of vast data archives collected by the survey such as the National Landslide Database, National Geotechnical Database and digital geological maps. This susceptibility map has been extensively used by the insurance industry and has also been adopted for a number of externally funded projects targeting specific problems.

KeywordsBritish Geological Survey, Landslides, GeoSure, National Landslide Database

Hazard assessment and mapping of mass-movements in the EU

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The BGS has since developed a Geographical

Information System (GIS)-based system (GeoSure)

to assess the principal geological hazards across the

country (Foster et al. 2008, Walsby 2007, 2008).

One output is a GIS layer that provides ratings of

the susceptibility of the country to landsliding on

a rating scale of A (low or nil) to E (significant),

which has been simplified for Fig. 1. Importantly, a

high susceptibility score does not necessarily mean

that a landslide has happened in the past or will

do so in the future, but where a landslide hazard

is most likely to occur if the slope conditions are

adversely altered by a change in one or more of

the factors controlling slope instability (Fig. 1).

GeoSure is produced at 1:50,000 scale and can

be integrated to show the spatial distribution of

landslide susceptibility in relation to buildings and

infrastructure. According to the dataset, 350,000

households in the UK, representing 1% of all

housing stock, are in areas considered to have a

'significant' landslide susceptibility (Rated E).

GeoSure works by modelling the causative

factors of landsliding: lithology, slope angle and

discontinuities being of prime importance. This has

been made possible through the use of GIS due

to its ability to spatially display and manipulate

data (Soeters & Van Westen, 1996). The GeoSure

methodology uses a heuristic approach to assess and

classify the propensity of a geological formation to

fail as well as to score the relevant causative factors.

The BGS holds large amounts of information about

the lithological nature of the rocks and soils within

Great Britain. The National Geotechnical Physical

Properties database contains information on the

geographical distribution of physical properties

(such as strength) of a wide range of rocks and soils

present in GB. This information is vitally important

in determining the propensity of a material to

fail. The scores assigned to each lithology are

based on material strength, permeability and

known susceptibility to instability. Discontinuities

were assessed as an important causative factor

as they reflect the mass strength of a material, its

susceptibility to failure and its ability to allow water

to penetrate a rock mass. Scores were defined in

line with those used in the British Standard 5930:

Field Description of Rocks and Soils (British

Standards Institute 1990) and by Bieniawski (1989).

Analysis of known landslides showed that slope

angle is one of the major controlling factors and

this was derived from the NEXTMap digital terrain

model of Britain at a 5m resolution. The scores

for all the causative factors at each grid cell are

combined in an algorithm to give an overall score

based on the relative susceptibility to landsliding.

The method is flexible enough to allow alteration

(nationally or locally) of the algorithm in the future

and include other factors such as the presence and

nature of superficial deposits.

Fig. 1: GeoSure layer showing the potential for landslide hazard Abb. 1: GeoSure-Schicht veranschaulicht das Potential von Rutschungsgefährdungen.

Hazard assessment and mapping of mass-movements in the EU

GIS and advises that citizens consult geological

maps and the now defunct Department of the

Environment Landslide Database. These sources

of information have been superseded by the BGS’s

‘GeoSure’ and continually updated National

Landslide Database. Despite the availability of

these resources, national guidance has never

been updated to take this into account. Despite

the advances in landslide mapping and hazard

mapping, there is still no legal compulsion to use

or consider it within a planning application in GB.

Development of landslide susceptibility maps and

databases in GB

BGS began to map geological hazards digitally in

the mid 1990’s. These early steps have paved the

way for the development of much more detailed

hazard maps that cover the whole of Great Britain

and are complimented by detailed landslide

mapping and an extensive National Landslide

Database (NLD).

The first systematic assessment of

hazards was triggered by the insurance industry

after it identified a need to better understand

geological hazards. Insurance losses caused

by ground movements (including subsidence)

between 1989 and 1991 reached around £1-

2bn following a particularly dry period and, as

a result, a digital geohazard information system

(GHASP – GeoHAzard Susceptibility Package)

was developed by the BGS. This first decision

support system (DSS) gave a weighted averaged

result for each of the 10000 postcode sectors

in GB and came to be used by around 35% of

the Industry (Culshaw & Kelk, 1994). Since

the development of GHASP, improvements in

GIS technology and the availability of digital

topographical and geological mapping for 98%

of GB have led to advances in the methods used

to map geohazard potential.

landslides. The majority of the legislation can

be interpreted as placing responsibility with the

developer, utility operator or landowner to ensure

landslides are not an issue.

The main source of regulatory

information regarding slope instability issues

is contained within Planning Policy Guidance

Note 14 (PPG14) and its associated Annex (Anon

1990, 1994). The Annex sets out the procedure for

landslide recognition and hazard assessment and

emphasises the need to consider ground instability

throughout the whole development process from

land-use planning, through design to construction.

These documents provide recommendations

that slope instability be considered in any

planning decision. If landsliding is a known

issue, ‘a developer’ must provide evidence that

any development activity will not exacerbate

landslide activity and that any building will be

safe. However, PPG14 is not legally compulsory

and only recommends that the local planning

authorities should endeavour to make use of

any relevant expertise when assessing whether a

planning application may be affected by ground

instability. The guidance notes do not specifically

refer to geological or geotechnical expertise

but details of some information sources of are

provided, including BGS data. Despite this, there

is no legal compulsion for a planning authority

to understand the extent or nature of landslide

hazards within their area of concern and, thus,

include them in planning decisions. Building

regulations put further emphasis on the role of

the developer to control the impact of instability

requiring that “The building shall be constructed

so that ground movement caused by…. land-slip

or subsidence (other than subsidence arising from

shrinkage), in so far as the risk can be reasonably

foreseen, will not impair the stability of any part of

the building.” (Anon. 2004).

The current PPG14 predates the era of

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'style of activity.' Whilst the NLD follows the

style of activity definitions, it has simplified the

state of activity terms defined by Varnes (1978)

into active, inactive and stabilised whilst also

adding descriptions on the state of development

(Advanced, degraded, incipient). Whilst activity

state and style have been described in the WP/

WLI definitions (WP/WLI, 1993), age has been

somewhat neglected. Data for modern landslides

observed either at the time of the event or through

comparison of aerial photographs and geological

mapping, is included in the NLD. To record cause,

the NLD has incorporated both triggering and

preparatory factors, limited to those most likely to

be identifiable and relevant in GB. The definitions

are based upon the WP/WLI (1990).

Further adaptations of landslide susceptibility maps

in Great Britain

Following the creation of the Geosure

methodology, BGS has worked within a

consortium including the Transport Research

Laboratory (TRL) and the Scottish Executive to

create a digital hazard layer specifically for debris

flows. This work was triggered in August 2004

following a period of intense rainfall which led

to two debris flows trapping 57 motorists on the

A85 trunk road in Scotland. As a consequence

of this event and others during the same period,

the Scottish Executive commissioned a study to

assess the potential impact of further debris flows

on the transport network of Scotland (Winter et

al., 2005). BGS was involved in the provision of a

GIS layer highlighting slopes susceptible to debris

flows. Debris flows, one of the five main types

of landslides, have a specific set of preparatory

criteria which differs from translational and

rotational slides. This modified assessment

sought to digitally capture this set of criteria and

create a layer showing areas where debris flows

are most likely to occur in the future. An initial

study determined five main components which

should be considered when determining the

hazard potential of debris flows affecting the road

network:

1. Availability of debris material

2. Hydrogeological conditions

3. Land use

4. Proximity of stream channels

5. Slope angle

It was considered that information regarding each

of these could be extracted from existing digital

datasets. The resulting interpreted data were

combined to produce a working model of debris

flow hazard that could be validated by comparing

with known events (Fig. 2). The A85 debris flow

event in 2004 is shown alongside the modelled

susceptibility layer, existing drainage channels

are shown as particularly susceptible to failure

through debris flows. Whilst the assessment of

debris flows highlights areas where they may

occur in the future, it does not attempt to model

the run-out of such failures.

Future Developments

Currently, work is ongoing to validate the current

methodology against statistical methods such

as bivariate statistical analysis and probabilistic

methods. The GeoSure method is based upon

expert knowledge and a heuristic approach

which is being tested against more statistic-based

approaches to assess its validity. Naranjo et al.,

(1994) consider statistical methods to be the

most appropriate method for mapping regional

landslide susceptibility because the technique is

objective, reproducible and easily updateable.

Bivariate analysis for instance relies upon the

availability of landslide occurrence and causal

parameter maps, which are compared against

dictionaries have been produced using

internationally recognised terminology. For

landslide type, the dictionary definitions follow

the conventions set out by Varnes (1978), the

EPOCH project (Flageollet, J.C., 1993) and the

WP/WLI (1990). Age and activity of a landslide

are important factors to record within a landslide

inventory. Temporal landslide data is as important

to understanding the geomorphic evolution of an

area as the spatial distribution of slides. However,

it is extremely difficult to date ancient landslide

events with any degree of accuracy and, as such,

the ages assigned to landslides only provide an

arbitrary indication of age. The WP/WLI (1990)

regrouped the Varnes (1978) definitions on

age and activity under the following headings:

'state of activity,' 'distribution of activity' and

Another important tool to both inform and assess

landslide susceptibility in GB is the National

Landslide Database (NLD). Landslide databases

are commonplace in Europe but there is variability

in their complexity and amount of further work

carried out to further enhance or update the

datasets. Assessing an area’s susceptibility to

landsliding requires knowledge of the distribution

of existing failures and also an understanding of

the causative factors and their spatial distribution.

This type of information is only available from a

detailed database of past events from which one

can draw out relevant information which may

inform the user of where landslides may occur

in the future. The National Landslide Database

is the most comprehensive source of information

on recorded landslides in GB and currently holds

records of over 15,000 landslide events (Fig.

2). Each of the 15,000+ landslide records can

hold information on over 35 attributes including

location, dimensions, landslide type, trigger

mechanism, damage caused, slope angle, slope

aspect, material, movement date, vegetation,

hydrogeology, age, development and a full

bibliographic reference. A fully digital workflow

has been developed at BGS to enable capture

of landslide information. The first stage of the

process involves using digital aerial photograph

interpretation software (SocetSet) to capture

digital landslide polygons which can then be

altered through field checking using BGS·SIGMA

mobile technology (Jordan 2009; Jordan et al.

2005). BGS·SIGMAmobile is the BGS digital field

data capture system running on rugged tablet PCs

with integrated GPS units, and is used extensively

for all geological mapping activities within the

British Geological Survey (Jordan et al., 2008).

When collecting landslide information,

either for the NLD or for digital maps,

internationally recognised standards have been

followed where appropriate. The database

Fig. 2: Distribution of landslide database points from the National Landslide GIS database. OS topography © Crown Copyright. All rights reserved.

Abb. 2: Verteilung der Rutschungs-Datenbankpunkte von der National Landslide GIS Datenbank. OS Topographie © Crown Copyright. Alle Rechte vorbehalten.

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distributed data and causal factor information

contained in the National Landslide Database of

Great Britain, assesses the landslide susceptibility

in Great Britain. It uses a heuristic approach to

model the causative factors that cause these

events. It assesses and classifies the propensity of

a geological formation to fail as well as to score

the relevant causative factors (e.g. slope angle).

By using these methodologies and datasets, a

national assessment of the potential hazard to

landsliding mass movement events in Great

Britain can therefore be undertaken.

Anschrift der Verfasser / Authors’ addresses:

Dr. Helen J. Reeves

Head of Science Land Use

Planning & Development

British Geological Survey,

Kingsley Dunham Centre,

Keyworth, Nottingham.

United Kingdom, NG12 5GG.

Direct Tel:- +44 (0)115 936 3381

Mobile:- +44 (0)7989301144

Fax:- +44 (0)115 936 3385

E-mail:- hjre@bgs.ac.uk

Literatur / References:

ALEOTTI, P., AND CHOWDHURY, R. 1999. Landslide hazard assessment: Summary review and new perspectives. Bulletin Engineering Geology and Environment, Vol. 58, pp. 21–44.

ANON. (1990). Planning Policy Guidance 14: Development on Unstable Land. Department of the Environment, Welsh Office. Her Majesty's Stationery Office, London.

ANON. (1994). Planning Policy Guidance 14 (Annex 1): Development on Unstable Land: Landslides and Planning. Department of the Environment, Welsh Office. Her Majesty's Stationery Office, London.Anon. (2004). The Building Regulations 2000 (Structure), Approved Document A, 2004 Edition. Office of the Deputy Prime Minister. Her Majesty's Stationery Office, London.

CULSHAW, MG & KELK, B (1994). A national geo-hazard information system for the UK insurance industry - the development of a commercial product in a geological survey environment. In: Proceedings of the 1st European Congress on Regional Geological Cartography and Information Systems, Bologna, Italy. 4, Paper 111, 3p.

BIENIAWSKI Z T (1989).Engineering Rock Mass Classifications. Wiley Interscience, New York, 272 p

BRITISH STANDARDS INSTITUTE. (1990). BS 5930. The Code of practice for site investigations. HMSO, London, 206 p

EARLY, K.R. & SKEMPTON, A. 1972. Investigation of the landslide at Walton's Wood, Staffordshire. Quarterly Journal of Engineering Geology, 5, 19-41.

FLAGEOLLET, J. C. (Ed) 1993. Temporal occurrence and forecasting of landslides in the. European Community. EPOCH (European Community Programme).

FOSTER, C, GIBSON, AD & WILDMAN, G (2008). The new national landslide database and landslide hazards assessment of Great Britain. In: Sassa, K, Fukuoka, H & Nagai, H + 35 others (eds), Proceedings of the First World Landslide Forum, United Nations University, Tokyo. The International Promotion Committee of the International Programme on Landslides (IPL), Tokyo, Parallel Session Volume, 203-206.

JORDAN, C. J., 2009. BGS∙SIGMAmobile; the BGS Digital Field Mapping System in Action. Digital Mapping Techniques 2009 Proceedings, May 10-13, Morgantown, West Virginia, USA, Vol. U.S. Geological Survey Open-file Report.

JORDAN, C. J., BEE, E. J., SMITH, N. A., LAWLEY, R. S., FORD, J., HOWARD, A. S., AND LAXTON, J. L., 2005. The development of digital field data collection systems to fulfil the British Geological Survey mapping requirements. GIS and Spatial Analysis: Annual Conference of the International Association for Mathematical Geology, Toronto, Canada, York University, 886-891.

NARANJO, J.L., VAN WESTEN, C.J. AND SOETERS, R. 1994. Evaluating the use of training areas in bivariate statistical landslide hazard analysis: a case study in Colombia. International Institute for Aerial Survey and Earth Sciences. 3 : 292–300

SKEMPTON, A. & WEEKS, A. 1976 The Quaternary history of the Lower Greensand escarpment and Weald Clay vale near Sevenoaks, Kent. Philosophical Transactions of the Royal Society, A, 283, 493-526.

SOETERS, R. & VAN WESTEN, C.J. 1996. Slope instability recognition, analysis and zonation. In: Transportation Research Board Special Report 247, National Research Council, National Academy Press, Washington, D. C., 129-177.

SUZEN, M.L. AND DOYURAN, V. 2004. A comparison of the GIS based landslide susceptibility assessment methods: multivariate versus bivariate. Environmental Geology, 45, 665- 679.

THE BUILDING AND APPROVED INSPECTORS REGULATIONS (Amendment). 2006. HMSO.

TOWN AND COUNTRY PLANNING ACT. 1990. HMSO.

VARNES D. J.: Slope movement types and processes. In: Schuster R. L. & Krizek R. J. Ed., Landslides, analysis and control. Transportation Research Board Sp. Rep. No. 176, Nat. Acad. oi Sciences, pp. 11–33, 1978.

WALSBY, JC (2007). Geohazard information to meet the needs of the British public and government policy. Quaternary International, 171/172: 179-185.

WALSBY, JC (2008). GeoSure; a bridge between geology and decision-makers. In: Liverman, D.G.E., Pereira, CPG & Marker, B (eds.) Communicating environmental geoscience. Geological Society, London, Special Publications, 305: 81-87.

WINTER, M. G., MACGREGOR, F & SHACKMAN, L (Eds) 2005. Scottish Road Network Landslides Study. The Scottish Executive. Edinburgh. WP/ WLI. 1993. A suggested method for describing the activity of a landslide. Bulletin of the International Association of Engineering Geology, No. 47, 53-57.

WP/ WLI. (International Geotechnical Societies UNESCO Working Party on World Landslide Inventory) 1990. A suggested method for reporting a landslide. Bulletin of the International Association of Engineering Geology, No. 41, 5-12.

Hazard assessment and mapping of mass-movements in the EU

in the future by numerical methods for smaller,

regional studies.

Further adaptations to the GeoSure

methodology, similar to those used to assess

debris flows, are planned for the future. Rock fall

hazard could be another type of mass movement

that is investigated using the heuristic GeoSure

approach applying different causal factors and

scoring algorithms.

Conclusion

In Great Britain, landsliding does not have a

structured regulatory framework, but historical

events, such as the Aberfan disaster and Scottish

debris flow events (Winter et al, 2005), have

highlighted the importance of understanding

the distribution and mechanisms that cause

landslide mass movement events in Great Britain.

The BGS GeoSure methodology, using spatially

each other to create a weighted value for each

parameter determined by calculating the landslide

density (Aleotti and Chowdhury, 1999 and Süzen

and Doyuran, 2004). Results from an initial pilot

study suggest that, in small areas, where detailed

landslide mapping exists, bivariate (conditional

probability) and probabilistic approaches are able

to more accurately predict landslide susceptibility

than GeoSure. However, this approach only

works where landslides have been mapped. This

technique cannot be used where no landslide

mapping has been undertaken. Another issue

with the conditional probability technique is that

it relies on the assumption that all the parameters

are mutually exclusive. The value of the heuristic

approach is its ability to highlight areas where

there are no known landslides but where there is

existing knowledge on the underlying causative

factors. The heuristic approach is able to produce

national scale assessments which could be refined

Fig. 3a: Extract from the debris flow susceptibility layer along with b: the Glen Ogle debris flow of 2004. Abb. 3a: Ausschnitt der Gefahrenhinweiskarte für Muren, gemein-sam mit b: dem Murgang in Glen Ogle, 2004.

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processes, a large variety of maps and methods

are used in the different European countries to

prevent natural disasters.

Exactly this variety, which reaches

from simple danger mappings to legally binding

“Hazard Zone Plans” (Gefahrenzonenplan),

should be shown inside this part of the AdaptAlp

project. However main goal of work package 5

(WP 5) is not only the description of this variety, but

a development of a “least common denominator”

which includes the minimum requirements for the

creation of Danger, Hazard and Risk maps.

This article focuses on the AdaptAlp

“Expert Hearing” from 17 March 2010 take place

in Bolzano and which dedicates the contents of

work package 5. In the following sections, the

main goals of this meeting and the contributions

from the involved experts were shown. In the

final chapter, first basic approaches concerning a

possible synthesis out of the big variety of “hazard

planning methods” is pointed out.

1. Introduction

In dealing with geological hazards today,

geotechnical (active) and spatial (passive)

measures come to implementation to minimize

risk. Because of a time limitation of active

measures (e.g. protective walls) and the decrease

of space for permanent settlings, spatial planning

gets more and more important. Due to avalanche

catastrophes in the 1950’s which were affecting

large parts of the Alps, in 1954 in the Swiss

municipal Gadmen, the first “Avalanche-Zone-

Plan” was passed. This was the first time a natural

hazard was considered in spatial planning (cf.

Glade a. Felgentreff 2008, p 160f).

Nowadays, almost 60 years later, “hazard

mapping” is a central part in risk management.

Countless types of “Danger, Hazard and Risk

maps” are produced for all kinds of risks. With

regard to natural hazards, especially geological

Hazard assessment and mapping of mass-movements in the EU

Zusammenfassung:Das AdaptAlp Workpackage 5 „Expert Hearing“ am 17. März 2010 in Bozen wurde von 28 Ex-perten aus acht Ländern besucht und widmete sich inhaltlich vollständig den Zielen von Action 5.1: Der Aufbau eines mehrsprachigen Glossars zu Hangbewegungen und insbesondere die Erarbeitung von Mindestanforderungen zur Erstellung von Gefahrenkarten. Neben einer kurzen Vorstellung des Projektfortschrittes und der weiteren Vorgehensweise hinsichtlich der Erarbeitung eines mehrsprachigen Glossars wurde von Vertretern aus allen beteiligten Ländern der jeweilige „State oft the Art“ bezüglich Gefahrenkartierung vorgestellt. Ausgehend von diesen Präsentatio-nen, welche die Grundlage für das weitere Vorgehen bilden, wurden im Anschluss an das Treffen Kurzzusammenfassungen für jede Region verfasst, welche innerhalb eines Gesamtberichtes auf der AdaptAlp Homepage (www.adaptalp.org) einzusehen sind. In einem weiteren Schritt wur-den auf Basis dieser Beiträge zwei Tabellen erstellt, welche einerseits alle verwendeten Karten strukturiert nach verschiedenen Typen und andererseits unterschiedliche Charakteristiken von Karten zusammenfassen und auf Länderebene vergleichen. Mithilfe dieser Matrizen werden Ge-meinsamkeiten und Unterschiede zwischen den beteiligten Regionen sichtbar und ein „kleinster gemeinsamer Nenner“ kann erarbeitet und in einem nächsten Meeting (Dezember 2010) fixiert werden. Ergebnis dieses Vorgehens und des Projektteiles wird eine Zusammenstellung von Min-destanforderungen zur Erstellung von Gefahrenhinweiskarten und Gefahrenkarten sein.

International Comparison: Summary of the Expert Hearing in Bolzano on 17 March 2010

Internationaler Vergleich: Zusammenfassung des Expert Hearings in Bozen vom 17. März 2010

KARL MAYER, BERNHARD LOCHNER

Summary:The AdaptAlp work package 5 “Expert Hearing” on March 17th, 2010 in Bolzano was attended by 28 experts from eight countries. It was dedicated to the goals of action 5.1: The creation of a multilingual glossary on landslides and especially the elaboration of minimum requirements for “hazard mapping”. Beside a short presentation on the progress and the further approach of the multilingual glossary, the “state of the art” in hazard mapping for each involved region was presented by several people responsible. Based on these presentations, which build the basis for the further approach, short abstracts were composed for each region. These short descriptions can be seen inside the official Hearings report published on the AdaptAlp Homepage (www.adaptalp.org). In a further step, based on these abstracts and the presentations, two tables were created. On the one hand, all used maps were grouped according to different types and on the other hand diverse characteristics of maps were summarized and compared at the country level. With these matrices, similarities and differences between the involved regions become visible and a “least common denominator” could be elaborated. These denominators should be discussed at the next meeting (December 2010) and, as a result, a compilation of minimum requirements to the creation of “Danger, Hazard and Risk maps” will be published.

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“harmonisation”. Within the hearing in Bolzano,

the plenum discussed the possible commitment

of such a report for each country. However the

title of the project contained the term “minimum

standards”, which rather sounds like a legal

term, the involved experts decided to switch to

word standards with “requirements”. So this legal

character is avoided and the final report will

include a part with “minimum requirements to the

creation of danger, hazard and risk maps”.

4. Short summary from the “expert-contributions”

in Bolzano

In the following sections, the “state of the art -

presentations” from several experts in Bolzano are

shown in short summaries for each country.

4.1 Germany

In Germany, geogenic natural hazards, such

as mass movements, karstification, large scale

flooding, as well as building ground that is

affected by subsidence and uplift, shall in future

be recorded, assessed and spatially represented

using a common minimum standard. An

important component for developing danger maps

is the construction and evaluation of landslide

inventories (e.g. landslide or sinkhole inventories).

The recorded data in the inventories should have a

minimal nationwide standards and are divided into:

• Main data on the topic area mass

movements and subrosion / karst with

information about the spatial positioning,

about determination of coordinates, etc.

• Commonly shared technical data of

the subject area mass movements and

subrosion / karst with information about

the date of origin, about the land use and

about damage, etc.

• Specific technical data of the subject area

mass movement and subrosion / karst

• Surface data concerning subsidence and

uplift

Regarding landslides, slide, fall, flow and

subrosion processes are recorded in the

inventories. Methods lasting from field studies to

computerized modelling are used for the creation

of these “danger maps”. In Germany, danger

maps serve as a first estimation of possible natural

hazards caused by certain geological conditions

and should serve as a planning reference for

possible investigations of individual objects where

necessary. On the danger map, the areas in which

natural hazards are possible are not delineated

precisely and local conditions (e.g. prevention

schemes, topographic peculiarities) are not taken

into consideration in every case. Because of these

reasons, it is recommended adding the following

annotations for each subject area:

“The following map was created for a

1:25,000 scale and is not precise. It serves as a

first estimation of possible engineering geological

hazards and cannot replace a geotechnical

survey. Areas within the immediate vicinity of

danger fields can also be affected. The intensity

and probability of a possible event cannot be

extracted from the map.”

4.2 Austria

At this time there is no regulatory framework or

technical norm concerning mass movements in

Austria. Only the course of actions concerning

floods, avalanches and debris flows are regulated

by law. This includes the generation of “hazard

zoning maps” (“Gefahrenzonenplan”). These are

generated by the Austrian Service for Torrent and

Avalanche Control (Forsttechnischer Dienst für

Wildbach- und Lawinenverbauung, WLV).

Hazard assessment and mapping of mass-movements in the EU

addressed inside a short presentation at the

beginning of this meeting. The rest of this one-day

session was dedicated to the contents of hazard

mapping. Due to this and the fact that the glossary

part is already described in detail within chapter

2.6 of this publication, this article only refers to

the hazard mapping part.

3. Hazard mapping in the Alpine regions

At the beginning of this chapter, it is important

to clarify that, because of the scheduled timing

of the project, at this time no final results can be

presented. Nevertheless, the theoretical approach

and the already achieved marks can be shown. In

general the course of action in getting a “synthesis”

to hazard mapping is structured in three steps.

First step is the evaluation of the “state of the art”

in hazard mapping in each country involved.

Exactly this point was the intention and the

main goal of the hearing in Bolzano. Two main

questions remained to be answered:

• What kinds of danger, hazard and risk maps

are officially applied in each country?

• Which standards are these maps based on?

To answer these questions, each participant gave

a short overview of the official used danger,

hazard and risk maps and also information on

the creation of such maps were given in short

presentations.

The second step will be the

“harmonisation” of the different methods used in

several countries. Therefore similarities should be

worked out and the “least common denominator”

in the methods of hazard mapping should be

found. This second step is to be discussed in detail

in the next workshop at the end of 2010.

The final part will be the creation

of a report, which includes the results of this

2. Main goals of the “Expert Hearing”

The topics of the expert hearing are all about the

goals of the AdaptAlp Work package 5 – “Hazard

Mapping”:

“Hazard zones are designated areas

threatened by natural risks such as avalanches,

landslides or flooding. The formulation of these

hazard zones is an important aspect of spatial

planning. AdaptAlp will evaluate, harmonise and

improve different methods of hazard zone planning

applied in the Alpine area. Focus will be on a

comparison of methods for mapping geological

and water risks in the individual countries. A

glossary will facilitate transdisciplinary and

translingual cooperation as well as support the

harmonisation of the various methods. In selected

model regions, methods to adapt risk analysis to

the impact of climate change will be tested. This

should support the development of hazard zone

planning towards a climate change adaptation

strategy. The results will be summarized in a

synthesis report (www.adaptalp.org).

The official description of WP 5 shows

two main parts (goals), which are worked out in

Action 5.1 under the leadership of the Bavarian

Environment Agency (LfU) in collaboration with

the alpS – Centre for Natural Hazard and Risk

Management in Innsbruck and with the inputs

from the international experts of the project

partners.

The two main goals are the elaboration

of a “multilingual glossary to landslides” and the

development of “minimum standards to create

danger, hazard and risk maps”.

As announced in the introduction,

the main focus of the hearing in Bolzano lies

on the elaboration of basics for the definition

of minimum standards for hazard mapping.

Therefore the progress of the glossary was only

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for developing these maps are outlined in the

federal guideline where a three step procedure is

proposed:

1) Firstly, an indispensable prerequisite for the

landslide hazard identification is obtaining

information about past slope failure events:

the maps of phenomena and the registration

of events (database).

2) Secondly, hazard assessment implies the

determination of magnitude or intensity

over time. Five classes of hazard are

determined in Switzerland: high danger

(red zone), moderate danger (blue zone),

low danger (yellow zone), residual danger

(yellow-white zone) and no danger (white

zone).

3) Based on the hazard maps and risk analysis,

three kinds of measures can be then taken

(third step): planning measures, technical

measures and organizational measures.

4.5 France

The plan for prevention of natural hazards (plan

de prévention des risques naturels prévisibles -

PPR) established by the law of 2 February 1995

is the “central” tool of the French State's action

in preventing natural hazards. The elaboration

of the PPR is conducted under the authority of

the prefect of the department, which approves it

after formal consultation of municipalities and a

public inquiry. The PPR is achieved by involving

local and regional concerned authorities from the

beginning of its preparation. It can handle only

one type of hazard or more and cover one or

several municipalities.

In the frame of this common procedure,

a general methodological guidelines document

has been published. One of these guideline

documents is dedicated to geological hazards,

which includes subsidence, sinking, collapse,

rock falls, landslides, and associated mud flows,

but excludes debris flows.

4.6 England

Up until 1966, the UK Government were not

interested in Geohazards, they were more

interested in finding oil and gas to help the UK

economy develop and expand. After the Aberfan

disaster (where 144 people, 116 of them children),

the UK government were much more interested

and funded a number of research projects to look

at the UK’s geohazards.

An inventory is the first step in

building an understanding of the occurrence of

geohazards. Currently BGS maintains two main

shallow geohazard databases: the National

Landslide and Karst Database (www.bgs.ac.uk).

These inventories provide the basis for analysing

the spatial distribution of the geohazard and

their causal factors. From this understanding

susceptibility can be assessed. In 2002, BGS

developed a nationwide susceptibility assessment

of deterministic geohazards such as landslides,

skrink-swell, etc. called GeoSure (http://www.bgs.

ac.uk/products/geosure/).

4.7 Spain (Catalonia)

The Parliament of Catalonia approved, with Law

19/2005, the creation of the Geological Institute

of Catalonia (IGC), assigned to the Ministry

of Land Planning and Public Infrastructures

(DPTOP) of the Catalonian Government. The

most important mapping plan is the Geological

Hazard Prevention Map of Catalonia 1:25,000

(MPRGC25M). As a component of the

Geoworks of the IGC, the strategic program

Hazard assessment and mapping of mass-movements in the EU

elementary form of a hazard map and, based

on this, enforce rules and obligations addressing

landslide hazard reduction: only existing hamlets

and villages can extend on dormant landslides;

on active ones, all new construction is forbidden.

Otherwise, the use of a purely descriptive

terminology (active, dormant), restricts the

usability of this map, being often obsolete, and is

therefore a frequent bone of contention.

In the federal state law from 11 August

1997, the base for the approval of guidelines to the

creation of hazard plans (Gefahrenzonenpläne) for

South Tyrol was laid. Also the role of municipalities

was defined to carry out the planning within

three years. Finally, the approval of plans and the

role of coinvolved partners are also part of this

law. The scale of this legal binding hazard plan

(“Gefahrenzonenplan”) in South Tyrol tends to the

working level of detail for the analyzed area. In

settlements, a 1:5,000 scale and in other regions a

1:10,000 scale is used and landslides, hydrological

hazards and avalanches are analyzed.

4.4 Switzerland

Switzerland is a hazard-prone country exposed

to many mass movements, but also to floods and

snow avalanches. Active and dormant landslides

take some 6% of the national surface. Most of the

landslides are very slow or slow reaching some

millimetres to centimetres of displacement per

year. Sudden slope movements with velocities up

to 40 m/s are also observed (e.g. rock avalanches).

The federal laws came into force in 1991 and are

based on an integrated approach to protect people

and property from natural hazards. The non-

technical, preventive measures are of particular

importance: land-use planning, zoning, building

codes. The reference documents in Switzerland

are the natural hazard maps. The techniques

As there are no legal instructions or standards

in Austria about if or how to deal with the

evaluation of mass movements, the federal states

are all following a different course of action.

The status of available data is very different in

the individual states. In some of the federal

states almost no data is available, others have a

lot of data but not digitally available. And then

there are states that can rely on a lot of digitally

available data and are working on generating

landslide susceptibility maps.

4.3 Italy (Piemonte, Emilia-Romagna, Province Bolzano)

In Italy the national law (high level, n. 445/1908)

and Royal Decree R.D. (n. 3267/1923) were the

first public regulations on land use planning. At

the beginning of ‘70s the land use management

was transferred to regions.

The national Law n. 183/1989

introduced land use planning at a basin scale.

The government sets the standards and general

aims without fixing a methodology to analyse and

evaluate the dangers, hazards and risks related

to natural phenomena. The same law designated

the Autorità di Bacino (Basin Authority) whose

main goal is to draw up the Basin Plan, a tool for

planning actions and rules for conservation and

protection of the territory.

One of the available tools produced by

ARPA Piemonte is the Italian Landslides Inventory

(IFFI). It is a national program of landslides

inventory, sponsored by national authorities and

made locally by the regions. It is the first try of

an inventory based on common graphical legend

and glossary.

The Emilia-Romagna Landslide Inventory

Map (LIM) reports over 70,000 landslides, while

the historical data base contains about 6,600

landslide events. LIM may be considered as an

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Comparison of different maps and their scales

Austria Germany Switzerland Slovenia Italy France Spain UK

Level Type of map GBA and Kärnten WLV Bayern CH Slovenia Arpa Piemonte South Tyrol Emilia

Romagna France Catalonia UK

basi

c

Geomorphologic map large scale variable scales 1:10,000 1:5,000 1:10,000 1:10,000 variable

Geotechnical map 1:5,000-1:50,000 1:200,000

Engineering geological map 1:5,000 (landslides) 1:250,000

inve

ntor

y

Level of attention Municipal

Inventory map 1:25,000 to 1:50,0001:5,000 to 1:2,000 and 1:25,000 to 1:50,000

1:10,000-1:25,000

1:10,000-1:50,000 (M1), 1:2,000-1:10,000 (M2), 1:5,000-1:2,000 or bigger (M3)

>1:50,000 1:10,000 1:10,000 1:25,000-1:100,000

1:10,000 - 1:25,000 1:10,000

Multi-temporal inventory map

Map of phenomena 1:50,000 and bigger

1:10,000-1:50,000 (M1), 1:2,000-1:10,000 (M2), 1:5,000-1:2,000 or bigger (M3)

1:10,000 1:5,000 or 1:10,000

variable scales 1:25,000 and bigger

1:10,000-1:50,000

susc

epti-

bilit

y Map of area of activity 1:25,000 1:10,000 1:10,000-1:50,000

Landslide susceptibility map, danger map

(Gefahrenhinweiskarte)

1:200,000 (K, regional), 1:50,000 (St., local) 1:25,000 1:10,000-1:50,000 1:250,000 1:10,000 yes

1:25,000 (2000) 1:5,000 (2009)

1:25,000 1:50,000

haza

rd

hazard index map K, Bleiberg: 1:10,000

Hazard map 1:2,000-1:10,000 1:25,000 1:10,000-1:25,000 1:25,000

Detailed Study (Detailstudie) 1:5,000-1:2,000 or more 1:10,000 1:5,000 -

1:1,000

Hazard zone map (Gefahrenzonenkarte)

not smaller than 1:50,000, usually 1:2,000 to 1:5,000

1:5,000; 1:10,000

Hazard zone map of the development plan 1:10,000 1:5,000;

1:10,000 1:5,000

risk

Map of potential damage 1:5,000; 1:10,000

Vulnerability map 1:250,000

Risk zoning map, risk map 1:5,000; 1:10,000

Fig. 1: Comparison of different maps and their scales Abb. 1: Vergleich unterschiedlicher Karten und deren Maßstab

Hazard assessment and mapping of mass-movements in the EU

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xx

xx

xx

xx

xx

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xx

xx

xx

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xx

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xx

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xx

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logy

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xx

xx

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xx

xx

xx

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xx

x

litho

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xx

xx

xx

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xx

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)x

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join

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xx

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xx

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xx

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xx

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mat

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xx

xx

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tain

ty/

relia

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info

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x

Inve

stig

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ns, r

epor

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tion

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eren

ces

incl

uded

xx

xx

xx

xx

Bib

liogr

aphy

incl

uded

xx

xx

xx

Hazard assessment and mapping of mass-movements in the EU

Seite

168

Seite

169

Anschrift der Verfasser / Authors’ addresses:

Karl Mayer

Bavarian Environment Agency (LfU)

(Office Munich)

Lazarettstraße 67

80636 Munich – GERMANY

Bernhard Lochner

alpS – Centre for Natural Hazard and Risk

Management

Grabenweg 3

6020 Innsbruck - AUSTRIAText

Literatur / References:

CRUDEN, D.M. & VARNES, D.J. (1996): Landslide types and processes. In A. Keith Turner & Robert L. Schuster (eds), Landslide investigation and mitigation: 36-75. Transportation Research Board, special report 247. Washington: National Academy Press.

FELGENTREFF, C. & GLADE, T. (Hrsg.) (2008): Naturrisiken und Sozialkatastrophen. Spektrum Akademischer Verlag, Heidelberg, 454 S.

KOMAC, M. (2005): Probabilistic model of slope mass movement susceptibility - a case study of Bovec municipality, Slovenia. Geologija, 48/2, 311-340.

KOMAC, M. & RIBIČIČ, M. (2006): Landslide susceptibility map of Slovenia at scale 1:250.000. Geologija, 49/2, 295-309.

KOMAC, M., KUMELJ, Š. & RIBIČIČ, M. (2009): Debris-flow susceptibility model of Slovenia at scale 1: 250,000. Slovenia. Geologija, 52/1, 87-104.

MAYER, K. & POSCHINGER, A. von (2005): Final Report and Guidelines: Mitigation of Hydro-Geological Risk in Alpine Catchments, “CatchRisk”. Work Package 2: Landslide hazard assessment (Rockfall modelling). Program Interreg IIIb – Alpine Space.

MAYER, K., Patula, S., Krapp, M., Leppig, B., Thom, P., Poschinger, A. von (2010): Danger Map for the Bavarian Alps. Z. dt. Ges. Geowiss., 161/2, p. 119-128, 10 figs. Stuttgart, June 2010

RAETZO, H., LATELTIN, O., TRIPET, J.P., BOLLINGER, D. (2002): Hazard assessment in Switzerland – codes of practice for mass movements. Bull. of Engineering Geology and the Environment 61(3): 263-268.

RIBIČIČ, M., KOMAC, M., MIKOŠ, M., FAJFAR, D., RAVNIK, D., GVOZDANOVIČ, T., KOMEL, P., MIKLAVČIČ, L. & KOSMATIN FRAS, M. (2006): Novelacija in nadgradnja informacijskega sistema o zemeljskih plazovih in vključitev v bazo GIS_UJME : končno poročilo. Ljubljana: Fakulteta za gradbeništvo in geodezijo (in Slovene).

Hazard assessment and mapping of mass-movements in the EU

5. Conclusion

As mentioned in the introduction of this article,

the “state of the art in hazard mapping“ in the

involved countries isn’t in balance. This fact was

also confirmed inside the “Expert Hearing” in

Bolzano.

To solve this problem, in a first step the

big variety of maps applied in the several regions

was summarized in one table (see Fig. 1). This chart

builds the basis for further actions concerning

the creation of minimum requirements. It is

structured into different levels and the associated

type of maps. The levels lasting from “basic” (e.g.

geomorphologic maps) over “inventories” (e.g.

inventory map), “susceptibility” (e.g. susceptibility

map) and “hazard” (e.g. hazard map) to “risk”

(e.g. risk map).

Furthermore, a matrix (see Fig. 2)

with specified characteristics and information

collected for different maps was created out

of the great wealth of information given at the

hearing in Bolzano. In particular, this table should

help to find accordance’s between the different

approaches. All the characteristics used in any

involved country (e.g. inventory) form the basis

for the definition of minimum requirements to

“hazard mapping”.

Finally, out of these two matrices a

recommendation will be created and, based

thereon, the final minimum requirements should

be fixed in the next workshop on December 2010

in Munich. The final report on the whole project

will include a chapter with the decided minimum

requirements to the creation of “Danger, Hazard

and Risk maps”.

aimed to acquiring, elaborating, integrating and

disseminating the basic geological, pedological

and geothematic information concerning the

whole of the territory in the suitable scales for

the land and urban planning. This project started

in 2007. In the MPRGC, evidence, phenomena,

susceptibility and natural hazards of geological

processes are represented. These processes are

generated by external geodynamics (such as slope,

torrent, snow, coastal and flood dynamics) and

internal (seismic) geodynamics. The information

is displayed by different maps on each published

sheet. The main map is presented on a scale of

1:25,000, and includes landslide, avalanche

and flood hazard. Hazard level is qualitatively

classified as high (red), medium (orange) and low

(yellow). The methods used to analyze hazards

basically consist of geomorphologic, spatial and

statistical analysis.

4.8 Slovenia

Legislation, planning and prevention measures are

not satisfying in the field of landslides in Slovenia

and the primary activities are still focused on

remediation instead on the prevention measures.

The updated Act on Spatial planning from

2007, governing natural disasters also discusses

problems with mass movements, but a common

methodology and procedures to prevent geology-

related natural disasters does not exist yet.

At the moment for Slovenia, a

“landslide susceptibility map” (scale 1:250,000)

and a “debris-flow susceptibility map” (scale

1:250,000) is elaborated by the Geological Survey

of Slovenia. In addition to this, a probabilistic

model of slope mass movement susceptibility for

the Bovec municipality in north-western Slovenia

was developed based on the expert geohazard

map at scale 1:25,000 and several other relevant

influence factors.

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170

AdaptAlp

DI Maria Patek, MBABundesministerium für Land- und Forstwirtschaft,

Umwelt und WasserwirtschaftAbteilung IV/5Marxergasse 3

1030 Wien

Tel.: 01/711 00 - 7334Fax: 01/71100 - 7399

E-Mail: die.wildbach@lebensministerium.at