Geoelectrical Method to Determine Andesite Rock Potential in Kepuh, Ciwandan District, Cilegon City

Abstract

The Kepuh area has abundant andesite rock resources. These rocks can be used as building materials and for other infrastructure. Based on this, it is necessary to research the potential of andesite resources. The tools used for this research are a resistivity meter, meter, current and potential wires, electrodes, hammer, battery, a global positioning system (GPS), handy talky, laptop and software (IP2win). The research applies the geoelectric method, which measures rock resistivity values. This geoelectric investigation uses the Schlumberger array. The advantages of the Schlumberger array are that fewer electrodes need to be moved for each sounding, and the cable length for the potential electrodes is shorter. Schlumberger soundings generally have better resolution, greater probing depth, and less time-consuming field deployment. The data obtained from the measurements were processed using IP2win software by entering the magnitude of the current, the value of the potential difference, and the electrode. The results of geoelectrical interpretation, the rocks found in the research area are topsoil, tuff, and andesite lava. The resistivity value of the topsoil in the study area mostly varies from 26.3 – 116 ohms – meters, tuff has resistivity values range of 18.8 – 84.2 ohms – meters, and Andesite lava has a resistivity range of 128 - 570 ohms – meters. The average thickness of topsoil is 1.4 meters, the average thickness of tuff is 25.9 meters, and the average thickness of andesite lava is 42.6 meters. Based on the average thickness, andesite rock can be the main commodity.