Integration of Fuzzy Sets, AHP, and TOPSIS Methods for Estimation of Liquefaction Potential Zones in Wates Groundwater Basin, Kulon Progo, Special Region of Yogyakarta

Abstract

Abstract In regional development planning, geological, environmental, and socio-economic conditions must be considered. Among the crucial things is the potential for disasters in the region. The Wates Groundwater Basin area has great regional development potential, starting from the establishment of the New Yogyakarta International Airport (NYIA) to the Southern Causeway (JJLS) construction. Various developments are predicted to continue to grow along with the development of areas targeted by the government for this area so the mapping of potential disasters is necessary as a means of achieving Sustainable Development Goals (SDGs). One of the potential disasters in CAT Wates is a liquefaction disaster, which is supported by geological, hydrogeological, and seismic data in this area which is prone to liquefaction. To confirm this potential, this research was conducted using geological and hydrogeological data from previous studies. The result of this research is a more detailed and objective zoning map of the liquefaction potential even though it uses minimal data. This is done by integrating the Fuzzy Sets, AHP, and TOPSIS methods, while simultaneously validating the result using the Cone Penetration Test (CPT) data. The results show that the eastern and southern regions of the basin which are composed of river deposits and coastal deposits, respectively, have a high to very high relative vulnerability to liquefaction, while the central region of the basin has a low to moderate relative vulnerability, and the northern region of the basin tends to have relatively very low vulnerability. That result is aligned with the total thickness of the liquefiable layer from CPT data. It indicates that the combined method is proven to be reliable for liquefaction susceptibility spatial mapping. Thus, the result hopefully can be used as a reference for land use planning in the Wates Groundwater Basin area.