Track: Optimization

Abstract

A magnetic survey has been carried out in Kutasari District, Purbalingga Regency, Central Java, Indonesia in April 2019. The aim of this research is to interpret the distribution of subsurface andesite rocks qualitatively in the research area. The equipment used in this research are Proton Precession Magnetometer, Global Positioning System, compass, and other supporting tools. The final result is the local magnetic anomaly map with value of -1,238.13 – 1,892.40 nT. This local magnetic anomaly map show the anomalous sources distribution in the subsurface which is interpreted as andesite igneous rocks that dominate in the middle to northwestern of the research area. This result has been clarified by pseudogravity anomaly map and analysis of its horizontal gradient. The pseudogravity anomaly map which has value of -75.99 – 119.50 mGal represents the distribution of subsurface rocks density. Whereas the horizontal gradient map which has value of 0.0022 – 0.3305 mGal/m represents the subsurface rocks lithological boundaries. Both of them shows the distribution of subsurface anomalous sources which is interpreted as andesite rocks tends to be western of the research area.