Potential Areas of Land Subsidence in Karst Landscape: Case Study in Ponjong and Semanu District, Gunungkidul Regency, Yogyakarta, Indonesia

Abstract

Sinkhole is a depression of the land surface, causing hazardous effects on the karst landscape. Land subsidence is a phenomenon of sinkhole formation due to karstification. Land subsidence associated with any of the existing evaporite-karst sinkholes Land subsidence is a gradual settling or sudden sinking of the Earth’s surface, which can be very dangerous as it relates to life on the surface and infrastructure planning. Ponjong and Semanu District, Gunungkidul Regency, are included in the Gunung Sewu Karst area, with landscapes highly influenced by the karstification process. Decision-makers need increasing attention to make assessments also mitigation on karst management. This study aims to determine the potential areas of land subsidence caused by natural factors in the karst landscape in the Ponjong and Semanu District, Gunungkidul Regency using integrated geospatial technology. For making some maps, we initially need a process from SRTM. Land Surface Temperature map, The Normalized Difference Vegetation Index (NDVI) map, slope map, and geological map are integrated into a GIS platform using the scoring and matrix then the overlay method. Descriptive spatial analysis of potential subsidence area is based on land surface temperature, vegetation factor, slope inclination, and geological formation related to altitude. The results show that approximately 80 percent of Ponjong and Semanu District places are high potential land subsidence areas. Policymakers can use this distribution of the potential regions of land subsidence as essential spatial planning in Gunungkidul Karst, especially in Ponjong and Semanu district.