Building a Spatial Database for Earthquake Risk
Assessment and Management in the Caribbean
Jacob Opadeyi and Rehanna Jadoo
Department of Geomatics Engineering and Land Management,
The University of the West Indies , St. Augustine,
Trinidad, West Indies.
Email: [email protected]
•Housing developments on drainage channels and steep slopes
•Unapproved development and land squatting
•Voluntary approach to the use of building codes
•Active seismic activities with geological faults
•Low level of awareness on the impact of natural hazards
•Low level of real estate insurance
OUR VULNERABLE LAND MASS
Geomorphology and Land cover 2007
Roads and Building Density
Slope and Soils Erosion
THE CONSEQUENCES
Damage to Buildings in Haiti due to the Earthquake of 2010
Risk Management Framework
Description of intention Hazard
mapping
Vulnerability assessment
Estimation of magnitude of consequences
Estimation of probability of consequences
Risk estimation
Risk evaluation
Risk management
EARTHQUAKE RISK ASSESSMENT
What is Risk?
Risks are an integral part of life and since risk cannot be completely
eliminated, the only possible option is to assess and manage it.
The first step in risk assessment is to find out what the problems are.
This involves evaluating the significance of a given quantitative
measure of risk in an integrated way.
EARTHQUAKE RISK ASSESSMENT
Earthquake risk assessment encompasses the range of studies required to estimate the
likelihood and potential consequences of a specific set of earthquakes of different
magnitudes and intensities.
Seismic scientists and engineers provide the key decision-makers with a description of the
nature of the earthquake risk in specific regions as well as the degree of uncertainty
surrounding such estimates.
Quantitative estimates of seismic risk are important for judging whether earthquakes
represent a substantial threat at any location as they enable objective weighting of
earthquake risk relative to other natural hazards and other priorities for making design
and retrofit decisions (NRC, 1996.)
Methods
4 major steps (Batuk et al 2005)
1. Hazard Analysis – quantifies the physical characteristics of a hazard, including probability of occurrence, magnitude,
intensity, location, influence of geological factors
2. Exposure Analysis – identifies and maps underlying elements at risk or exposures, including the built environment and
socioeconomic factors such as population and economic activity
3. Vulnerability Analysis: Assesses the degree of susceptibility to which elements at risk are exposed to the hazard. A
common form of vulnerability analysis uses historical damage records to prescribe relationships between damage to
dwellings and hazard intensity, for example different buildings and construction types will have distinct vulnerability
curves, and finally
4. Risk analysis synthesizes the above three components and determines the resulting losses as a function of return
period or as an exceedance probability: e.g.
RISK ($$/YR) = SUM( HAZARD [YEAR-1] X ASSETS [$$] X FRAGILITY [0-1])
Uses of Earthquake Risk Assessment (C. Benson and J. Twigg, 2004)
•Predicting the expected impact of earthquakes
•Identification of appropriate risk management strategies
•Predicting the impact a project would have on forms and level of vulnerability in the
wider community
•Help to formulate national policy objectives such as land use planning and building
codes
• it provides cost efficient decision support on how to optimize investments into risk
reducing measures in three situations, namely, prior, during and after an earthquake.
Data Required for Earthquake Risk Assessment
A. Baseline data
- Administrative boundary
- Land cover, roads, streams etc.
- Transportation and utility system
- Facility and building structures
- Demography (census, population distribution, density)
- Economic value of asset of various sectors
Data Required for Earthquake Risk Assessment
B. Hazard data
Historical records (time, place, extent, magnitude / intensity) of earthquake hazard
Geology, lithology, soil, and slope, water table
Faults location, length, and depth
Site condition, ground motion
Existing method in hazard & risk assessment methodology
Data Required for Earthquake Risk Assessment
C. Vulnerability data
Proximity of assets to active and inactive fault lines
Age of structures
Population and development density
Value of assets
Location of critical facilities: Hospitals, Schools, Prisons, Banks, Public offices
Construction materials used in buildings
Location of lifelines: telecommunication, water, gas, power, transport systems
EARTHQUAKE RISK MANAGEMENT
What is Risk Management?
Risk management means reducing the threats to life, property and the environment
posed by the hazard whilst simultaneously accepting unmanageable risks and
maximizing any associated benefits (Smith, 1996.)
Risk management involves the efforts of a variety of sectors and series of actions.
In the case of earthquakes, risk management describes the role of seismic monitoring
in developing alternative strategies for reducing future losses and aiding the
recovery process.
Earthquake Risk Management Measures
National risk reduction program
Disaster preparedness and
response plans
Disaster recovery plans (National
and sectoral)
Earthquake hazard maps
Earthquake early warning systems
Landuse planning
Building codes and development
regulations
Insurance schemes
Development incentive programmes
Efficient risk communication strategies
Public education (use of simulators)
Research and development
programmes
Earthquake risk policy and legislation
Example of Seismic Assessment Products
Figure 1 Colour Coded Seismic Hazard Map pubs.usgs.gov/fs/2003/fs017-03/images/useqs.gif; Figure 2 Source: www.consrv.ca.gov/cgs/rghm/psha/Pages/index.aspx; Figure 3Source:
Seismic risk mapping in Germany, Tyagunov et al 2006
Case Study: Comprehensive Earthquake Risk Reduction
Program and Action Plan: Marikina
Task 1. Stakeholder User Needs Assessment: The first task will identify primary
stakeholder concerns and interests. Using available GIS data and scenario modeling, it
characterized stakeholder concerns in terms of known earthquake risk to valued
community assets.
Task 2. Data Inventory
•Comparison of existing GIS data resources with needs emerging from Task 1
•Analyzes data collection and integration issues.
Task 3. Risk Assessment
•Formalization of findings from a risk assessment regarding loss of housing, critical
infrastructure, and economic development opportunities resulting from a 7.0 Magnitude
earthquake.
Peak Ground Acceleration Map Overlaid on landuse to show
areas subject to Heavy Shaking
Peak Ground Acceleration Map & Critical Facilities Subject to
Heavy Shaking
Comprehensive Earthquake Risk Reduction Program and Action Plan: Marikina
Task 4. Prepare Conceptual Earthquake Risk Reduction Plan.
This task created a conceptual framework based on a strategic planning process
It assesses implementation options for the Comprehensive Earthquake Risk Reduction
Program including locally feasible goals and objectives, policies/strategies and
programs/projects for mitigation, preparedness, response, and recovery.
Comprehensive Earthquake Risk Reduction Program and
Action Plan: Marikina
Task 5. Plan Refinement and Implementation Strategy
This task combined objectives, policies, strategies, programs and projects for mitigation,
preparedness, response, and recovery actions into a Draft Comprehensive Earthquake Risk
Reduction Program and Action Plan based on discussions held at stakeholders workshop.
Task 6. Produce Final Products
This task will include finalization of the Program and Action Plan along with Web-based
materials.
Feature Identity Database
The feature identity database is made up of variables that provide general information about the facility e.g. location, name, contact information, name of person in charge etc.
Many of these variables can be collected in the field using mobile GPS/GIS technology.
Fac_ID
P_KEY
Nfac_
Code
Fac_Type Name Address Locality Tel Fax
23 12 Health center
Chaguanas District Health
Facility
Corner Galt St. and Chaguanas
Main Rd. Chaguanas 665-8958
24 61 Police Station Chaguanas Police Station Railway Rd. Chaguanas 665-5271
25 41 Air Field / Runway
National Helicopter Services
Ltd. NHSL Heliport, Camden Couva 679-2628 679-2345
26 XX XXXXXXXXX XXXXXXXXXXXXXXXXXXX XXXXXXXXXXXXXXXXXXXXXX XXXXX XXXXXXX XXXXXX
27 XX XXXXXXXXX XXXXXXXXXXXXXXXXXXX XXXXXXXXXXXXXXXXXXXXXX XXXXX XXXXXXX XXXXXX
28 XX XXXXXXXXX XXXXXXXXXXXXXXXXXXX XXXXXXXXXXXXXXXXXXXXXX XXXXX XXXXXXX XXXXXX
Feature Amenities Database
The feature amenities database is made up of variables that provide information about the facility’s service amenities .
This data should be collected by the relevant agency (government / private) responsible for the facility.
Amen
_ID
Fac_ID
F_KEY
Floor_space Parking_sp Parking_
sz
Generator Water
_cap
Pump Toilets_
unisex10
23 2400 20 70 YES XXX YES XX
1124 XXXXXXXXXX XX XXXXXX YES XXX YES XX
1225 XXXXXXXXXX XX XXXXXX YES XXX YES XX
1326 XXXXXXXXXX XX XXXXXX
1427 XXXXXXXXXX XX XXXXXX
1528 XXXXXXXXXX XX XXXXXX
Feature Functions Database
The feature functions database is made up of variables that provide information about the facility’s
operations.
These variables will depend on the type of facility. For example, the variables for a medical facility will
include : Number of beds, Number of doctors, Number of nurses etc.
This data should be collected by the relevant agency (government / private) responsible for the facility.
Fac_ID P_KEY Health_
Beds
N_Doctors N_Nurses N_Ambulances N_Drivers T_staff
2360 XXX XXX XX XX XXXX
32136 XXX XXX XX XX XXXX
3495 XXX XXX XX XX XXXX
36200 XXX XXX XX XX XXXX
Structural Integrity Database
The structural integrity database is made up of variables that provide
information about the integrity of the facility’s construction design.
This data should be compiled by engineering, construction and inspection
experts, in coordination with the relevant agency (government / private)
responsible for the facility.
Examples of variables that should be included and assessed include
vulnerability of building foundation, columns, beams, supporting walls etc.
These variables can be further broken down into more detailed evaluations and
tests as deemed necessary by relevant experts.
This information can be used to asses the facility’s structural vulnerability to the
effects of earthquakes or other natural disasters.
Structural Integrity Database
Struc
_ID
Fac_ID
F_KEY
Found_v
uln
Column_
vuln
Supp_walls
_vuln
Beam
_vuln
Floor_slab
_vuln
yrs_safe
_usage
Damage
_history
Earthquake
Response
Possible
closure_reccom
100 23 XX XXX XXX XX XX XXXX
101 32 XX XXX XXX XX XX XXXX
102 34 XX XXX XXX XX XX XXXX
103 36 XX XXX XXX XX XX XXXX
Compiling the National Built Assets Database
Chaguanas District Health CenterFAC_ID 23
Feature Amenities Database Feature Identity Database
Feature Functions Database Structural Integrity Database
Hyperlink images of facility and building plans. Front View
Side View
1st Floor
2nd
Floor
3rd Floor
Synchronization of Data with ArcGIS
Query & Analyse National Database of Built Assets
Many questions can be answered by querying and analysing this database, along with the
associated bio-physical characteristics of the land, providing decision-support for
policymakers:
How many built assets throughout the country require seismic retrofitting?
Which facilities have been designated as shelters in the event of a natural disaster?
Where are these shelters located?
What is the potential monetary loss/replacement cost should one/more of these built
assets collapse due to an earthquake?
Which facilities exist within the most hazardous zones?
In the event of an evacuation how many occupants will require special assistance?
Building Density in Anguilla
Building Density in Antigua
Building Density in Tortola
What are the Challenges facing the Development of Earthquake
Risk Assessment and Management in Trinidad & Tobago?
Lack of a consistent data collection programme for risk
assessment and management.
Lack of an active public education programme.
A need for capacity development and enhancement
Review of relationship with related agencies
Lack of a database on building structures
Vulnerability assessment of communities
Obtaining political support
Thank you