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Soil Information Working Group (SIWG) ESBN Plenary, London, 2005 Identifying Risk Areas for Landslides Florence Carre (JRC, Subgroup leader), D. Seebach,

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Presentation on theme: "Soil Information Working Group (SIWG) ESBN Plenary, London, 2005 Identifying Risk Areas for Landslides Florence Carre (JRC, Subgroup leader), D. Seebach,"— Presentation transcript:

1 Soil Information Working Group (SIWG) ESBN Plenary, London, 2005 Identifying Risk Areas for Landslides Florence Carre (JRC, Subgroup leader), D. Seebach, N. Filippi, M. Pizziolo, G. Bertolini, A. Poschinger, J. Fortuny- Guasch, M. Gemmer

2 Soil Information Working Group (SIWG) ESBN Plenary, London, 2005 LANDSLIDE Movement of a mass of rock, debris, earth down a slope (Cruden & Varnes, 1996) LANDSLIDE CLASSIFICATION TYPES OF MOVEMENT TYPE OF MATERIAL Bedrock Soils Coarse Grained Soil Fine Grained Soil FallsRock fallDebris fallEarth fall TopplesRock toppleDebris toppleEarth topple Slides Rotational Rock slideDebris slideEarth slide Translational Lateral spreads Rock spread Debris spreadEarth spread FlowsRock flowDebris flowEarth flow Complex: Combination of two or more types of movement (Cruden & Varnes, 1996)

3 Soil Information Working Group (SIWG) ESBN Plenary, London, 2005 MAIN CAUSES Snow melt and heavy rainfall events water saturation DRIVING FACTORS RELATED TO VULNERABILITY OF SOIL Geology/bedrock material Slope Land cover Soil permeability TRIGGERING MECHANISMS Rapid snowmelt Intense rainfall Water level change Human activities Changes in landuse/land cover Earthquakes / volcanic eruption

4 Soil Information Working Group (SIWG) ESBN Plenary, London, 2005 MAIN SOIL VARIABLES AFFECTED BY LANDSLIDES Affected soil physical properties: - structure; - bulk density; - water permeability; Loss of soil functions and increase of soil vulnerability to other threats - erosion - soil organic matter decline - compaction (but also as a driving factor)

5 Soil Information Working Group (SIWG) ESBN Plenary, London, 2005 Tier I Source: EPSON (European Spatial Planning Observation Network) project espon/Landslides.htm

6 Soil Information Working Group (SIWG) ESBN Plenary, London, 2005 Tier II approach Synoptic or territorial scale maps (> 1:50,000): inventories maps used by planning agencies to direct allocation of funds, develop emergency preparedness plans and similar tasks Usually 3 scale maps (Van Westen, 1993) Medium scale maps (> 1:20,000 to 1: 1:50,000): used for preliminary or regional landslide hazard assessments and feasibility studies followed by more detailed work Detailed scale maps (> 1:5,000 to 1: 1:500): Prepared as part of a landslide hazard assessment of a specific site and should be accurate enough to guide layout of individual structures or specific operations or to plan mitigation

7 Soil Information Working Group (SIWG) ESBN Plenary, London, 2005 Common criteria (1) Common criteria to delineate landslide risks - Spatial probability of occurrence of landslides (like density of landslide/km²) - For tier I approach, landslides have to be defined in a common way by all the MS in order to compare the density - For tier II approach, the 3 scale maps can be produced according to the purpose

8 Soil Information Working Group (SIWG) ESBN Plenary, London, 2005 Common criteria (2) Common criteriaData source/type of information Data Quality /Resolution Tier 1Tier 2 occurrence/density of existing landslides statisticsNUTS III larger-scale regional/local assessments bedrock nature of material + presence of fissures and pores Sensitive bedrocks can be Gault Clay and Flish Map of Geology 1:1,000,000 higher resolution maps soil properties texture, structure, permeability not required for in Tier 1 classification/grouping according to? slopeclasses: 0-10°; 10°-30°; >30°250msame or higher land cover/land use infrastructure; cultivation density/pressure, mining Non relevant for Tier 1 100m climate likelihood of heavy rainfall events daily events (e.g. 70 mm/day) same or higher seismic riskthreshold?

9 Soil Information Working Group (SIWG) ESBN Plenary, London, 2005 Conclusions Intensify collaboration with EuroGeoSurveys (EGS) Elaborate on qualitative approach, since no operational approach has been presented Todays problems Improvements in harmonisation are necessary because: - inventories do not follow any commonly agreed standards or methodologies until now - authorities in charge of inventories are either local, regional or national and can be civil engineers, soil scientists or geologists Only landslides related to civil damages are listed, others can exist and not be listed (above all in unpopulated areas)


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