General geology and landslide susceptibility of Patuk Area, Gunung Kidul, Yogyakarta, Indonesia

Research was conducted around Patuk area in Gunung Kidul, Yogyakarta, Indonesia that was approximately 25km2 and the coordinates of the study area is 110°28´ to 110°31´0´´E at the longitude and 7°51´ to 7°54´0´´S at the latitude. The purpose of this study is to update the geological map of this study area in the scale of 1:25000, to analyse the impact probability and impact of landslide in the study area and also to analyse the landslide susceptibility analysis for cut in the study area using the ArcGIS software. The study area composed of three main lithological unit that is sandstone unit, volcanic breccia unit and also limestone unit. Based on the weightage overlay method in the ArcGIS software, the susceptibility of landslide in the study area was determined. Five parameters have been chosen in determining the landslide susceptibility that is slope, lineament density, the type of lithology, drainage density and also the type of soil in the study area. The weightage and score for each parameters had been assigned based on the references from the previous study. Five maps from each of the parameters have been produced and in the end the landslide susceptibility map of the the study area was made by overlaying all of the five maps. The zone of the susceptibility was divided into three that is the low susceptibility zone, moderate susceptibility zone and also the high susceptibility zone and it was later determined that slope is the most influenced to the landslide hazard because of the location of the study area itself that located on the hilly and mountainous area.