| Summary: | The existence of geothermal manifestations in Mount Rajabasa located in
South Lampung regency indicate a potential for geothermal energy in this area.
Study on the geological conditions and the geothermal system at Mount Rajabasa
has been done by integrating the ASTER image, DEM, magnetic and surface
geological data. ASTER image processing by defoliant method to detect surface
alteration minerals, while ASTERDEM to analyze lineaments and lithological
boundaries. 3D modeling of local magnetic anomalies to obtain the magnetic
susceptibility below the surface, while the petrographic and XRD analysis are used
to confirm lithologies and alteration types are generated.
The interpretation and processing data results showed that Mount Rajabasa
dominated by andesite lava and pyroclastic units with strato volcano geothermal
system. Structures in the study area is controlled by major faults with northwestsoutheast
direction, which is part of the Sumatra Fault system. The heat source
comes from volcano residual magma with a reservoir depth of ± 1000 meters from
surface and temperature of ± 220°C, which is located in the foothills of the southern
part. The existence of monogenetic volcanoes around the foot of the mountain are
expected to cause surface alteration were detected mostly acidic such as alunite,
cristobalite and kaolinite. While smectite alteration associated with cristobalite is
weakly acidic.
|
|---|