Geology of Cawas and the Demarcation of Groundwater Potential Zone Using 1D Electrical Resistivity Method in Tancep, Gunung Kidul, Yogyakarta

The study area located in a region of Yogyakarta which is Cawas, Klaten and the specification took place in Tancep, Gunung Kidul. The study area is a complex area which consists of 3 types of rocks in an area and has seven lithology which are schist-phyllite, nummulitic limestone, tuffaceous sandstone, volcanic clastic sandstone, sandstone interbedded with siltstone, diorite and also crystalline limestone. The objectives of this research are to produce a geological map of the study area with scale 1:25000 and to demarcate the groundwater potential zone in Tancep, Gunung Kidul. The specification area was chosen because it has lack of groundwater well that needed by the community for daily activities. This research is important in demarcating groundwater potential zone for new groundwater resources. In order to satisfy the objectives, method such as geological mapping, geomorphological investigation, data collection and data processing must be conducted. For the demarcation of the groundwater potential zone, the 1D electrical resistivity method (ERI) or vertical electrical sounding (VES) method were conducted using Schlumberger array arrangement. The results that were interpreted were there are two potential groundwater sources in the study area. The lithology and groundwater sources were determined by correlating the result with regional geology of the area and also by using the resistivity chart. This research will give significant to people around study area for the community as it can accommodate demand for new groundwater resources