| Abstract | A landslide susceptibility map was constructed for area west of Amphoe
Phi Pun , Nakhon Si Thammarat Province. The susceptibility rating takes into
account the underlying rock type, slope an gle , slope aspect, vegetation type,
soil thickness, terrain and geological structure. A series of thematic maps were
constructed. The maps generated are geologic map, slope map, aspect map,
veget ation map, s oil t hickness map, terrain unit map and geological structure
map. Rock units exposed are granite, quartzite, slate, red mudstone, silt and
shale. Surficial deposits are composed of natural levee deposits, backswamp
deposits, alluvial fan deposits, colluvial deposits I, collu.vial deposits II,
undifferentiated ch annel fill and debris flow deposits. The vegetation type can
mainly be classified as tropical evergreen forest, old plantation, young plantation,
paddy fields, and land cover. The terrain units are gener ally divided into granitic
rocky hills and metamorphic rocl{y hills. Geometry of the slope can be defined
as creep slope a nd wash slope . The slope and aspect map were also deve loped
based on topographic map using the Digitial Elevation Models (DEM). From the
distribution of slope failures based on the data of 1183 landslides in the study
area, the susceptibility score are defined and developed for each of the important
factors using the GIS approach. Different weights were assigned to all variables
to identify the area of high, moderate, and low landslide susceptibility. |