Geology of Arjosari geothermal area, Pacitan, East Java

A geological survey has been performed at Arjosari geothermal area, Pacitan, East Java. Hot springs, alterationrock, and other surface manifestations indicate possible geothermal energy potential of the area. Geologically four primary rocks are found in the area. Those are sandstone and volcanic breccia of Mandalika Formation, volcanic rocks of Arjosari Formation, igneous rocks on the bottom of the area and alluvium deposit. Regionally many igneous rocks are exposed as intrusive genetic. The volcanic and igneous rocks found in that area are faulted and have fractures making conductive and convective heat transfer happened to cause the generation of hot springs, alterationrock, and other surface manifestation of geothermal characteristics. With the existence of various volcanic and igneous rocks, the surface manifestation of hot springs and alteration rocks, it can be indicated the existence of geothermal resoucein the area.