Applications of Geophysical Methods for Geothermal Exploration in Tarutung

Geothermal exploration in Tarutung uses geoelectric and geomagnetic methods to effectively map subsurface structures and identify geothermal systems. These systems are formed by the complex interaction of tectonic and volcanic activity that controls fluid migration and determines reservoir characteristics. Both methods are suitable for renewable energy development such as Tarutung. 2-D resistivity results show resistivity values ranging from 10 to 525 Ωm. Values between 10 and – 16.2 Ωm indicate the presence of groundwater, values between 31.2 and – 74 Ωm indicate denser rocks indicating a geothermal reservoir, while 112 – 525 Ωm usually indicates massive, dry rocks or dense sandstone that does not act as a reservoir. The magnetic residue map shows geomagnetic values between 14 and 30 nT, indicating a geothermal source, while susceptibility values ranging from 0.0013 × 10-³ to 0.0088 × 10-³ reflect limestone and sandstone rocks.