Identification of subsidence hazard zone by integrating engineering geological mapping and electrical resistivity tomography in Gunung Kidul karst area, Indonesia

Abstract

The presence of natural cavities in karst morphology may cause severe civil engineering and environmental management problems. Karst formations will limit the expansion of urbanization, especially infrastructure development in limestone areas. Geophysical methods, especially electrical resistivity tomography (ERT) techniques, are effective and efficient solutions to detect voids below the surface. This study aimed to develop a subsidence hazard map as basic information for infrastructure development. The identification was made by measuring electrical resistivity tomography on eight profiles in the infrastructure development plan. In addition, it was also supported by geological mapping, particularly the structural geology and types of rocks around the site. The research area consists of massive limestone, bedded limestone, and cavity limestone with generally north-south joints. The analysis of geological mapping data and electrical resistivity tomography measurements showed that the cavity limestone was identified with a north-south elongated pattern in line with the fracture pattern found on the surface at the research area. The surface lithology type, the geological structures density, and the subsurface lithology were used to develop a subsidence hazard map. This information is beneficial in determining the safe location of infrastructure development based on disaster risk mitigation.

Anthropogenic activity effect on water quality of epikarst spring in the western part of Gunungsewu Karst Area, Java Island, Indonesia

“…Karst aquifers are easily polluted because they have complex hydrological systems in the form of diffuse, fissure, and conduit (Zhang et al, 2011;Geyer et al, 2013;Massinai et al, 2023). In addition, karst has unique geomorphology in such a manner that it can directly carry pollutants to the groundwater system through sinkholes, karst windows, and ponds (Ravbar and Kovacic, 2015;Goldscheider, 2019;Wilopo et al, 2022). Pollution in dominant karst aquifers is caused by anthropogenic activities in the form of agriculture and household domestic waste (Richter et al, 2021;Brad et al, 2022;Putro and Wilopo, 2022).…”