1

Using the TRIGRS Model to Predict Rainfall-Induced Shallow Landslides Over

Large AreasGioia, E.1, Speranza, G.2, Ferretti, M.2, Marincioni, F. 1,

Godt, J. W.3, and Baum, R. L.3

(1) Department of Life and Environmental Sciences, Marche Polytechnic University, Via BrecceBianche, Ancona, 60100, Italy, e.gioia@univpm.it;

(2) Regional Forecast Center, Marche Region, Via del ColleAmeno 5, Ancona, 60126, Italy; (3) U.S. Geological Survey, Box 25046 MS 966, Denver, CO 80225-0046

EGU General Assembly 2014 May 2nd, 2014, Vienna

1. Introduction

2

USING THE TRIGRS MODEL TO PREDICT RAINFALL-INDUCED SHALLOW LANDSLIDES OVER LARGE AREAS

91%

9%

Landslides Floods

99% municipalities affected

(Ministry for the Environment, Land and Sea - Report 2008)

(pictures courtesy of the

Marche Civil Protection)

3

WARNING SYSTEM

FORECAST

EMERGENCY MANAGMENT

RECOVERY AND RESTORATION

PREVENTION

EVENT

USING THE TRIGRS MODEL TO PREDICT RAINFALL-INDUCED SHALLOW LANDSLIDES OVER LARGE AREAS

1. Introduction

LANDSLIDES FORECAST

• Hydrological features;• Hydrogeological features;• Geomorphological features;• Geotechnical features;• Structural features.

• Antecedent rainfall (A) ;• Rainfall intensity (I) ;• Rainfall duration (D) :• Probability

EMPIRICAL MODELS

(STATISTICAL)

PHYSICAL MODELS

(DETERMINISTIC)

4

USING THE TRIGRS MODEL TO PREDICT RAINFALL-INDUCED SHALLOW LANDSLIDES OVER LARGE AREAS

1. Introduction

  RANGE

c [kPa] c ≥ 0

[φ deg] > 0φ

ϒs [N m-3] ϒs > 0

D0 [m2 s-1] D0 > zmin

Ks [m s-1] Ks > 0

θr [-] θs > θr ≥ 0

θs [-] θs > 0

[α m-1] > 0α

𝑭𝒔=𝒓𝒆𝒔𝒊𝒔𝒕𝒊𝒏𝒈 𝒇𝒐𝒓𝒄𝒆𝒔𝒅𝒓𝒊𝒗𝒊𝒏𝒈 𝒇𝒐𝒓𝒄𝒆𝒔

5

USING THE TRIGRS MODEL TO PREDICT RAINFALL-INDUCED SHALLOW LANDSLIDES OVER LARGE AREAS

1. Introduction

TRIGRS(Transient Rainfall Infiltration and Grid-based Regional Slope Stability)

2. Study area

6

USING THE TRIGRS MODEL TO PREDICT RAINFALL-INDUCED SHALLOW LANDSLIDES OVER LARGE AREAS

THE POST-OROGENIC COMPLEX OF THE ESINO RIVER BASIN

LANDSLIDES (82) OCCURRED DURING THE PERIOD 1990-2012

7

3. Data collection

USING THE TRIGRS MODEL TO PREDICT RAINFALL-INDUCED SHALLOW LANDSLIDES OVER LARGE AREAS

RAIN GAUGES USED FOR THE STUDY

8

3. Data collection

USING THE TRIGRS MODEL TO PREDICT RAINFALL-INDUCED SHALLOW LANDSLIDES OVER LARGE AREAS

9

3. Data collection

USING THE TRIGRS MODEL TO PREDICT RAINFALL-INDUCED SHALLOW LANDSLIDES OVER LARGE AREAS

CLAY SANDY-CLAY LOAM GRAVEL

44

29

63

LAN

DSL

IDE

FREQ

UEN

CY

LANDSLIDES TEXTURE CLASSES

BOX PLOT CHARTS OF CENTRAL TENDENCIES

10

3. Data collection

USING THE TRIGRS MODEL TO PREDICT RAINFALL-INDUCED SHALLOW LANDSLIDES OVER LARGE AREAS

SETTINGS

11

STEP 1: TRIGRS calibration

USING THE TRIGRS MODEL TO PREDICT RAINFALL-INDUCED SHALLOW LANDSLIDES OVER LARGE AREAS

4. Method

SETTINGS

12

STEP 1: TRIGRS calibration 

STEP 2: Outline test cases, choose the rainfall event, select the rain gauge and the rainfall intervals

USING THE TRIGRS MODEL TO PREDICT RAINFALL-INDUCED SHALLOW LANDSLIDES OVER LARGE AREAS

4. Method

SETTINGS

13

STEP 1: TRIGRS calibration 

STEP 2: Outline test cases, choose the rainfall event, select the rain gauge and the rainfall intervals

STEP 3: Evaluate an “Antecedent Water Index”

USING THE TRIGRS MODEL TO PREDICT RAINFALL-INDUCED SHALLOW LANDSLIDES OVER LARGE AREAS

4. Method

SETTINGS

14

STEP 1: TRIGRS calibration 

STEP 2: Outline test cases, choose the rainfall event, select the rain gauge and the rainfall intervals

STEP 3: Evaluate an “Antecedent Water Index”

STEP 4: Construct input grids of slope from a 20m DEM, property zones, rainfall input, soil depth and water table depth

USING THE TRIGRS MODEL TO PREDICT RAINFALL-INDUCED SHALLOW LANDSLIDES OVER LARGE AREAS

4. Method

OCTOBER 1996 CASE STUDY

15

USING THE TRIGRS MODEL TO PREDICT RAINFALL-INDUCED SHALLOW LANDSLIDES OVER LARGE AREAS

5. Results

RECEIVER OPERATING CHARACTERISTICS (ROC) ANALYSIS

16

USING THE TRIGRS MODEL TO PREDICT RAINFALL-INDUCED SHALLOW LANDSLIDES OVER LARGE AREAS

5. Results

17

USING THE TRIGRS MODEL TO PREDICT RAINFALL-INDUCED SHALLOW LANDSLIDES OVER LARGE AREAS

6. Conclusion

We presented an innovative methodology for the application of a

physical model (TRIGRS) for rainfall-induced shallow landslides

forecasting over broad areas.

TRIGRS well predicts the instabilities, thus can be used to build an

accurate susceptibility map;

Rainfall-induced landslides over large regions may be predicted

even where geotechnical and hydraulic properties data as well as

temporal changes in topography or subsurface conditions are not

available.

18… Thank you