Perubahan Konsetrasi Unsur Terlarut pada Manifestasi Termal dan Implikasinya pada Model Konseptual Sistem Panas Bumi Tangkuban Perahu
Currently, there are two Contract of Works (CoW) exist for geothermal development within Tangkuban Perahu Area. The presence of these two separated contracts suggest that there were a speculation/hypothesis that two different geothermal systems lies within Tangkuban Perahu Area, which is either two different reservoirs or two separate heat sources. Based on the facts, this study aims to verify the earlier suggestions regarding to the sustainability aspects of the geothermal system during future developments.
Changes in the content of dissolved elements at thermal manifestations are identified and observed further to seek for any similarities, especially the content changing of Cl, F, B, and SO4 against the increased activity of Tangkuban Perahu Volcano. Moreover, these changes are suspectedly related to the increased magma activity at Tangkuban Perahu Volcano. Therefore, it is necessary to observe physical and chemical conditions at Domas Crater and manifestations at surrounding areas. Physical and chemical characteristics were observed at eight manifestations of thermal water, one cold springs, two rivers and the wells from August 2012 - July 2013.
Increased activities at Tangkuban Perahu is expected to be followed by the increase in content of Cl, F, B and SO4. However, when the activity of Tangkuban Perahu was increased, the content of F, B and SO4 are also increased at all manifestations especially at the center of Tangkuban Perahu, meanwhile the Cl content decreased. These facts raises the suspicion that there is a volcanic heat source in the middle of Tangkuban Perahu. Furthermore, residual gravity anomaly data shows the presence of another heat source at northeastern part of Tangkuban Perahu. Meanwhile, comparison of Cl-B and Na-K shows that there are two different reservoirs existing within Tangkuban Perahu i.e. volcanic reservoir and sediment reservoir. As a result, it can be concluded that the Tangkuban Perahu could be divided into two separate geothermal systems regarding to the presence of two different heat source and reservoirs.
Dr. Eng Suryantini ST. Dipl. Geothermal Tech., M.Sc