| Title | Remote Sensing Volcanostratigraphy as a Tool to Support Delineation of Geothermal System Boundary Associated with High Terrain – Composite Volcanic |
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| Authors | SURYANTINI, Hendro WIBOWO |
| Year | 2020 |
| Conference | World Geothermal Congress |
| Keywords | Volcanostratigraphy, high terrain, composite volcanic |
| Abstract | Field mapping in volcanic area is difficult because some lithology looks similar and thus lithology boundary of a volcanic rock unit might be misinterpreted. On the other hand, in a high terrain volcanic associated hydrothermal system this boundary might control the occurrence of thermal springs manifestation that may indicate the boundary of this system. This geothermal system boundary is important for predicting delineation of possible clay cap at depth that often correlates with top of reservoir extent. It also aid in designing geophysical survey and soil geochemistry survey. Thus, predicting the lithology boundary at the early stage of geothermal exploration is crucial. Mapping of volcanic lithology can be supported by interpretation of remote sensing data. In this paper we use ASTER DEM data to create digital elevation model. This data will be used to construct volcanostratigraphy units by delineation of ridges and rivers that will point to central of eruption or edifice. One edifice will form one volcanostratigraphy unit. The unit boundary subsequently is overlain and intersected with the occurrence of any thermal manifestation such as occurrence and chemistry of thermal springs and cold springs that were contaminated by thermal fluid. By understanding the hydrology of the area (hence high terrain volcanic geothermal system) and the assumption that the thermal anomaly coming from the young and active geothermal system, then area associated with geothermal system can be interpreted and geothermal system boundary can be delineated. The method has been applied in Patuha, Wayang Windu, and Karaha-Talaga Bodas geothermal field. It proves that geothermal system boundary is crucial in designing further exploration program such as geophysical survey and interpreting the extend of reservoir that may effect the calculation of resource. It can be concluded that this method is a potential tool to determine the boundary of geothermal system in particular in high terrain – composite volcanic hydrothermal system. However, applicability of this method in other volcanic type other than high terrain composite volcanoes still need to be studied. |