The Resistivity Structure of Aluvial in Geothermal Prospect Using Time Domain Electromagnetic Methode (TDEM) Survey

Abstract

Time-domain electromagnetic (TDEM) surveys were carried out around alluvial region, Sulili district, Pinrang regency, South Sulawesi province, Indonesia at 2013. The purpose of the study is to determine area of low resistivity geophysical data using Time Domain Electromagnetic Method. The surveys were a completion of the previously interpreted geological data collected from geological surveys at 2012. Interpretation of the recorded transient magnetic fields resulted in a general feature of the resistivity structure which was composed of three main layers: a low resistive layer (below 2 Ωm), a medium resistive layer (around 2-100 Ωm) and a high resistive layer (above 100 Ωm). Depend on geological formation, the high resistive layer was interpreted as andecite intrution, medium resistive layer was interpreted as aluvial, Tml, Tmpv or all of them formation and the low resistive layer was considered to be a complex of altered geological formation. The cross section of conductance distribution showed region near intrusion and hot water springs had low resistivity characteristic. This evidence was indicated that the cap rock of the reservoir near of the geothermal manifestation.