Preliminary investigation of volcano hosted geothermal area at Kasinan-Songgoriti-Cangar, Batu city, based on gravity-seismic methods

The initial stage of volcano hosted geothermal exploration, based on gravity-seismic methods, has been done at a volcano hosted geothermal area around Kasinan-Songgoriti-Cangar, Batu city, East Java, Indonesia. Based on surface observations, some hot springs were found at the locations. Simple gravity and seismic methods were applied to estimate the structure that controlled the hot springs, while the seismic method estimated the source position. The result of bouguer anomaly map analysis of the research area shows that the low bouguer anomaly value of 36.3 to 50.8 mGal estimated as host rock of the geothermal volcano system for Kasinan-Songgoriti area, while for Cangar area, the bouguer anomaly value ranged from 26.3 mGal to 89.5 mGl. Based on seismic method, about 11 epi-hypocenters have been estimated at a depth between 22-94 meters. These results were still a preliminary stage to study this area, in order to obtain more representative information, further research is needed such as a multi geophysical methods covering a larger area involving Mount Kawi, Mount Kelud, and Mount Arjuno-Welirang complexes.