Gas geochemistry analysis in Candradimuka Crater, Mount Lawu, Central Java, Indonesia

Abstract

Mount Lawu is a stratovolcano in Central Java that holds a large geothermal energy potential. Within Mount Lawu Geothermal Area, several thermal manifestations could be located one of them being Candradimuka Crater located at the proximity of Mount Lawu peak. This study aims to assess the gas geochemistry in Candradimuka Crater by obtaining gas sample within the crater area. Gas geochemistry analysis uses geothermometer, geoindicator, and N2-He-Ar ternary diagram to analyse the subsurface condition. The analysis reveals that the fluid circulating in the crater originated from meteoric water and that Mount Lawu reservoir temperature ranged between 250 C - 289 C. Based on geological observation and gas geochemistry, Candradimuka Crater is located within the upflow zone of Mount Lawu.