Eurac Geoframe Presentation

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  • 1. My experiences after Master SIGEO andLARAM SchoolCristiano Lanni, Ilaria Pretto University of Trento

2. PRESENTATION OUTLINES: 1st step: Landslide risk assessment 2nd step: evaluation of shallow landslideSusceptibility and Hazard map usingadvanced methods 3th step: tutorial on quantitative risk assessment 3. PRESENTATION OUTLINES 4. 1) Which type of landslide? TYPE OFMOVEMENT TYPEOFMATERIALVARNES, 1978 5. 1) Which type of landslide? SOME EXAMPLES 6. SOME EXAMPLES 7. SOME EXAMPLES 8. SOME EXAMPLES 9. Earth Slide Earth flow SOME EXAMPLES 10. LANDSLIDE IDENTIFICATION IS NOT ALWAYS AN EVIDENT TASK Understanding maps(topographic, geomorphological,..) Morphological evidences, deposits, vegetation, indirect evidence 11. 1) Which type of landslide? Understanding maps Aerial photo-interpretation 12. 1) Which type of landslide? MORPHOLOGICAL EVIDENCES 13. 1) Which type of landslide? MORPHOLOGICAL EVIDENCES 14. 1) Which type of landslide?DEPOSITION AREA kinematic reconstructionType of material 15. 1) Which type of landslide?DEPOSITION AREA kinematic reconstructionType of material 16. 1) Which type of landslide? DEPOSITION AREA kinematic reconstructionNEW STREAM PATH 17. 1) Which type of landslide?VEGETATION INDIRECT EVIDENCE 18. This is an essential part of any landslide zoning. It Landslide Inventory (I):involves the location, classication, volume, travel distance, state of activity and date of occurrence of landsliding in an area. Landslide Susceptibility (S): Areas prone to slope failure or that where a landslide may travel onto or retrogress into it.Landslide Hazard (H):The probability of occurrence within a specified period of time and within a given area of a potentially damaging phenomenon. Elements at Risk (Er): Means the population, properties, economic and social activity, etc., at risk in a given area.Vulnerability (V):Means the degree of loss of a given element or set of elements at risk of a given magnitude. It is expressed on a scale from 0 (no damage) to 1 (total loss). Specific Risk (Rs):Means the expected degree of loss due to a particular natural phenomenon. It may be expressed by the product of Hazard times Vulnerability Total Risk (R):Means the expected number of lives lost, person I S H R injured, damage to property, or destruction of economy activity due to a particular natural phenomenon, and is therefore the product of specific risk and element at risk 19. I S H R 20. I 21. I S 22. I S H 23. I S H R 24. R = ( H V ) Er = Rs Er I S HSTEFAN 25. Type of zoningI S H R 26. The SCALEREGIONAL SCALESMALL SCALE< 1:100,000 MEDIUM SCALE 1:100,000 1:25,000 BASIN SCALELARGE SCALE 1:25,000 1:5,000 DETAILED SCALE> 1:5,000LOCAL SCALE 27. The PURPOSE Indicative Typical Area Range of zoningExample of Zoning ApplicationLANDSLIDE INVENTORY AND SUSCEPTIBILITY SMALL SCALE< 1:100,000 > 10,000 km2 TO INFORM POLICY MAKERS AND THE GENERAL PUBLICLANDSLIDE INVENTORY AND SUSCEPTIBILITY1:100,000 1,000 ZONING FOR REGIONAL DEVELOPMENT, OR MEDIUM SCALE10,000 km2VERY LARGE SCALE ENGINEERING1:25,000 PROJECTS. PRELIMINARY LEVEL HAZARD MAPPING FOR LOCAL AREAS LANDSLIDE INVENTORY, SUSCEPTIBILITY AND HAZARD ZONING FOR LOCAL AREAS. LARGE SCALE1:25,000 100 INTERMEDIATE TO ADVANCED LEVEL1:5,0001,000 km2 HAZARD ZONING FOR REGIONAL DEVELOPMENT. PRELIMINARY TO INTERMEDIATE LEVEL RISK ZONING FOR LOCAL AREAS AND THE ADVANCED STAGES OF PLANNING FOR LARGE ENGINEERINGSeveralINTERMEDIATE AND ADVANCED LEVEL STRUCTURES, ROADS AND RAILWAYS DETAILED SCALE > 1:5,000 Hectares toHAZARD AND RISK ZONING FOR LOCAL AND1,000 km2SITE SPECIFIC AREAS AND FOR DESIGN PHASE OF LARGE ENGINEERING STRUCTURES, ROADS AND RAILWAYS INTERNATIONAL GUIDELINES (FELL ET AL., 2008) 28. Recapping:II S WHERE Frequency Assessment (of landslide or triggering factor)I S HWHERE, WHEN - Elements at risk - Temporal-spatial probability - Vulnerability WHERE, WHEN,I S HR WHAT, HOW MUCH 29. I S H R WHERE 30. Type of Zoning : our work at University of Trento I S H 31. I LOCATION CLASSIFICATION AREAL EXTENT AND VOLUME CREEPING ZONES STATE OF ACTIVITY 32. IIndividuation of the area where first - failure phenomenon or landslide reactivation can occur 33. I Mapping of the creeping zone allows the identification of the possible landslide evolution zones 34. I SHALLOW LANDSLIDES 35. I I.VELOCITY II. OLUMEVIII. NERGYE DEBRIS-FLOW, SHALLOW LANDSLIDE WITH COARSE-GRAINED SOILS DEEP LANDSLIDE WITH FINE- GRAINED SOIL 36. I S Landslides Inventory 37. I S 38. I S H 39. I S H Intensity Duration Return Time Source Area Deposition Area 40. I S HPROBABILITYTHAT A PARTICULAR DANGER (THREAT) OCCURSWITHIN A GIVEN PERIOD OF TIME IN A GIVEN LOCATIONType of LandslideFrequency TriggeringMagnitude/IntensityPropagation 41. I S H TYPEOF LANDSLIDE Frequency Triggering Intensity Propagation 42. I S H TYPE OF LANDSLIDE Frequency Triggering Intensity Propagation3 different approaches for landslides Intensity assessment1) HISTORICAL INFO, GEOLOGY AND TOPOGRAPHY Assess the relative intensity from the estimated Landslide volume and the expected landslide BASIC LEVEL velocity (qualitative)2) SIMPLE MODELS INTERMEDIATE LEVEL Estimate expected or observing landslide velocity3) NUMERICAL MODELS Calculate the kinetic energy (velocity) by means ofADVANCED LEVEL numerical models 43. I S HTYPE OF LANDSLIDE Frequency Triggering Intensity Propagation1) HISTORICAL INFO, GEOLOGY AND TOPOGRAPHY Assess the relative intensity from the estimated Landslide volume and the expected landslide velocity (qualitative)BASIC LEVEL 44. I S H TYPE OF LANDSLIDE Frequency Triggering IntensityPropagation requency of landslide can be determined from:F BASIC LEVEL: HISTORICAL DATA INTERMEDIATE LEVEL: RELATIONS WITH TRIGGERING EVENT FREQUENCY (I.E. RAINFALL, EARTHQUAKE) ADVANCED LEVEL: RELATING THE INDICATORS OR REVEALING FACTORS OF SLOPE STABILITY CONDITION (I.E. WATER CONTENT, GROUNDWATER LEVEL, PORE-WATER PRESSURE) TO TRIGGERING FACTORS (RAINFALL) 45. I S H TYPE OF LANDSLIDE Frequency TriggeringIntensityPropagationAN EXAMPLE OF APPROACH AT REGIONALSCALEDefinition of an INDEX OF SLIDE PRONE AREA INGiven by the ratio between the number of towns affected by landslides during an event NI and the total number of threatened towns in the study area NTIN = NI / NT Relative to a given return Time T [year] in order to define an annual frequency f [year -1] 46. I S H TYPE OF LANDSLIDEFrequency TriggeringIntensityPropagation For example by the definition ofRainfall Intensity-DurationThresholds, considering the rainfall that caused landslides inthe past and eventually thecumulative antecedent rainfall that predisposed to failurecondition 47. I S HType of LandslideFREQUENCY Triggering Intensity Propagation& (BASIC LEVEL) (INTERMEDIATE LEVEL) Care should be taken in the evaluation of landslide frequencies - ECAUSE THE HISTORICAL DATA COULD BE AFFECTED BY ERRORS B- ECAUSE THE CONDITIONS RESPONSIBLE FOR A GIVEN LANDSLIDE BFREQUENCY IN THE PAST MAY NO LONGER EXIST 48. I S H Type of Landslide FREQUENCYTriggering IntensityPropagation INITIAL CONDITION (ANTECEDENT SOIL MOISTURE)WATER TABLE LEVELRAINFALL (INTENSITY, DURATION, RETURN TIME) WATER CONTENT AND PORE-WATER PRESSURE PROFILE ADVENCED LEVEL 49. I S H Type of Landslide FREQUENCY TriggeringIntensityPropagation WATER TABLE LEVEL SAFETY FACTORS FS