IGME LANDSLIDE DATABASE AND A IGME LANDSLIDE DATABASE AND A REVIEW OF HAZARD ZONATION IN REVIEW OF HAZARD ZONATION IN

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Eleftheria PoyiadjiEleftheria PoyiadjiEngineering Geologist IGME Engineering Geologist IGME -- GreeceGreece

Member of EGS/WG Geohazards Member of EGS/WG Geohazards

InstituteInstitute of Geology and Mineral of Geology and Mineral ExplorationExploration(IGME) is the national geologigal survey of Greece (IGME) is the national geologigal survey of Greece and is the official geoscientific adviser of the and is the official geoscientific adviser of the government.government.

250 cases of landslides in 2.5 years250 cases of landslides in 2.5 yearsCreation of a database.Creation of a database.

Landslide consultancy Landslide consultancy projectprojectInstituteInstitute of Geology and Mineral of Geology and Mineral ExplorationExplorationCentral Union of MunicipalitiesCentral Union of Municipalities

Landslide databaseLandslide databaseAccess Access –– GISGIS

Data recorded:Data recorded:Geographic detailsGeographic details

Prefecture, municipality, year, season, coordinatesLocation

Elevation, land use, slope gradient, erosion, geotectonic zone, geological formation, lithological composition, hydrogeology, inclination of strata, thickenss of weathered zone, precipitation, manmade impact, groundwater level, seismic risk zone

Landslide dataLandslide data

Older history, type of movement, geometry, rate,

Landslide process

Triggering factor, causes, consequences, structures affected, proposed mitigation measurements, degree of compliance

Database includes mostly landslides that affect the Database includes mostly landslides that affect the urban environment, structures and lifelinesurban environment, structures and lifelines

The landslide database has been The landslide database has been included in geoincluded in geo--database ofdatabase of IGME IGME

Next step: Introduction of more than 2,000 reports on landslides (analogue)

Statistical analysis

A landslide hazard zonation map of Greece was A landslide hazard zonation map of Greece was produced in a scale of 1:500,000 according to the produced in a scale of 1:500,000 according to the number of landslides per 100Kmnumber of landslides per 100Km22

Methodology for the identification of Methodology for the identification of risk areasrisk areas

Factors Factors ““Driving forcesDriving forces””

They are related to the scope of risk They are related to the scope of risk mapping mapping –– different scalesdifferent scales

Risk zonation in urban areasRisk zonation in urban areasLarge scales (1:1,000)Large scales (1:1,000)

Multi hazard approachMulti hazard approach

Risk zonation in urban areasRisk zonation in urban areasLarge scales (1:1,000)Large scales (1:1,000)

Multi hazard approachMulti hazard approach

Risk zonation in urban areasRisk zonation in urban areasLarge scales (1:1,000)Large scales (1:1,000)

Multi hazard approachMulti hazard approach

Risk zonation in urban areasRisk zonation in urban areasLarge scales (1:1,000)Large scales (1:1,000)

Multi hazard approachMulti hazard approach

Risk zonation at national or european levelRisk zonation at national or european levelSmall scales (1:50,000, 1:100,000??)Small scales (1:50,000, 1:100,000??)

Common elements for the identification of Common elements for the identification of areas at risk of landslidesareas at risk of landslides

Directive of the European parliament and of the Directive of the European parliament and of the counsil counsil –– COM(2006) 232 finalCOM(2006) 232 final

Common elements for the identification of Common elements for the identification of areas at risk of landslidesareas at risk of landslides

Directive of the European parliament and of the Directive of the European parliament and of the counsil counsil –– COM(2006) 232 finalCOM(2006) 232 final

Seismic riskClimate

Land useLand cover

TopographyBedrock

Occurrence/density of existing landslides

Soil typological unit (STU) (soil type)

More driving forcesMore driving forces

Relevant orientation of strata relative to slope orientation *

Manmade factors

erosionDeforestation

PrecipitationGround water

* Applied only in large scale

CONCLUSIONSCONCLUSIONS

Common MethodologyCommon MethodologyFactors are related to:Factors are related to:

scalescalescopescope

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