Landslide Susceptibility Mapping in Yalova, Turkey, by Remote Sensing and GIS

Remote sensing and GIS (geographic information systems) techniques were used to map the landslide susceptibility in Yalova Province and to assess the landslide risk in its counties. The set of criteria investigated using GIS were determined as a result of a landslide literature survey. These criteria are geology, hydrology, terrain slope, vegetation cover, soil thickness, proximity to roads, soil moisture, and terrain aspect. Active/inactive landslide occurrences data were extracted from the 1:500,000 scale landslide maps prepared by the General Directorate of Mineral Research and Exploration of Turkey (MTA). Considering both the landslide occurrence statistics in the study area and the ranks given to the landslidecontrolling criteria in previous landslide studies available in the literature, these criteria were evaluated in GIS, resulting in classification of a province into none, low, moderate, and high landslide susceptibility areas. A comparison of the resulting map with the original landslide map prepared by the MTA revealed that 91.1 percent of the locations corresponding to active creeps, slides, and flows <5 m deep were ranked as either high or moderate landslide susceptibility areas in the newly created map, while this percentage was 75.7 percent for the active slides >5 m deep. The resulting map showed new landslide risk areas as well, which were not on the original map of the MTA. These may be worthwhile to investigate while updating the original map for new potential landslide area research.