| Title | The Geothermal Fields in Central Part of the Sumatra Fault Zone as Derived from Geophysical Data |
|---|---|
| Authors | Djoko Santoso, M. Emmy Suparka, Sayogi Sudarman and Surahman Suari |
| Year | 1995 |
| Conference | World Geothermal Congress |
| Keywords | Sumatra, geophysics, gravity, resistivity, subduction |
| Abstract | Sumatra island is a part of an island arc produced by oblique subduction process of the Indian-Australian Plate beneath Asia Plate. The main result is a large dextral strike-slip fault called the Great Sumatra fault. Magmatic activities related to the subduction process controls the volcanic chain along the major weak zone created by this fault system. High-enthalpy geothermal resources in the central part of the island are closely associated with these phenomena. They are most likely developed beneath the volcanic complexes area and fed by shallow rhyolitic to andesitic magma chamber. Geophysical data from two geothermal fields that are the Muaralaboh and Talang Mt. areas were analyzed. The methods used are gravity. magnetic, resistivity sounding, resistivity mapping, resistivity head-on, and very low frequency electromagnetics. Extensive and intensive surface geothermal features are found in both area. The most important structural features in these two geothermal fields as inferred by geophysical methods are faults associated with grabens. therefore is concluded that most geothermal system in central Sumatra are graben-type systems. |