Landslide hazard spatial analysis and prediction using by ltx81750


									 11th International Symposium on Natural and Human Induced Hazards &
 2nd Workshop on Earthquake Prediction

 Landslide hazard spatial analysis and prediction
   using GIS and Remote Sensing data in the
  Kythera Island, Southwestern Aegean, Greece
 1 Dept.of Earth & Atmos. Sciences, State University of New York, Albany NY 12222, New York,
                             U.S.A. (e-mail:
  2 Dept. of Geology and Geoenvironment National and Kapodistrian University of Athens, Ilisia

                                       GR15701, Greece

Many natural hazards in Kythera are the result of a combination of its tectonic formation,
geological structure, topography, and meteorological events. The most common such
hazards are earthquake, flood, landslide, avalanche and rockfalls. A GIS analysis of
Kythera Island reveals potential landslide areas. Since the island is located in a larger
region of high tectonic activity, the study is dependent on adequate local earthquake foci
data. For the purposes of this study, geology, topography, land use, vegetation indices,
stream and road networks were considered. ARCINFO and ERMAPPER were used
because of easy access, viewing and quick analysis of GIS and remote sensing data.
   This study compares the landslides induced by heavy rainfalls and large earthquakes
in the Kythera region over the last 20 years. We mapped the distribution and infer the
susceptibility to various kinds of mass movements (rock slides, to rock falls through earth
flows, debris flows and avalanches), triggered by earthquakes and heavy rainfalls. The
mass movement events are dependent to vegetation change (detected through NDVI
supervised classification of Landsat images), that were caused by road construction.
   This attempt to map landslide susceptibility was supported by additional field
observations, digitized road network, and geology data, SRTM data and GIS techniques.
Using certainty factor analysis, it was found that there is a good correlation between the
existing landslide areas and specific slope aspect range, which is consistent with the
existing faulting on the Kythera Island.
   A significant proportion of the inhabited areas of Kythera are at risk of landslide and
related mass movement damage. We anticipate that this mapping procedure will be used
to construct seismic or meteorological landslide hazard maps that will assist in
emergency preparedness planning and in making decisions regarding development and
construction in areas susceptible to slope failure triggered by earthquake or heavy

                                           University of Patras, Greece, 22-25 June 2006


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