Audio Magnetotelluric to Characterize Geothermal Prospect in Pacitan

Abstract

AMT (Audio Magneto Telluric) research is done by measuring the fluctuations in the magnetic field and also electric field which has recorded on Earth's surface. The survey is located in Kasihan Village as the part of Non-Seismic Practical work of Geophysics students 2010. There is a normal fault associated with igneous intrusions and above of that has identified as a surface layer unit, referred as a layer of alluvium. From the distribution of resistivity, the data interpolation of each sounding measurement can be made to geological model of the area for each line oh survey. The model has four lithology, which are: alluvium (resistivity 1.58 to 15.85 Ùm), sandy conglomerate rock (resistivity 25.12 to 158.49 Ùm),bottom layer is volcanic sandstone (resistivity 398.11 to 1000 Ùm) that is intruded by igneous intrusion. The reason why the topography of Pengajaran peak is higher than the surrounding areas is because composed by mostly dense igneous rocks (resistivity 1584.90 to 10,000 Ùm). The igneous rocks are also visible in several places around of Pengajaran peak. The research is being following up with the interpretation of Geothermal prospect in the area by analyzed the presence of intrusion in the geologic model from the AMT survey.