Geothermal Activity on the Flank of Sakurajima Volcano Inferred from Infrared Thermal Observation

Abstract

In June 2006, Showa crater on the southeastern flank of Minamidake, Sakurajima volcano erupted after 58 years silence. Geothermal observation has been repeated 5 times since March 2006, using an infrared thermal camera. The results of the observation were compared with the previous data. Thermal anomaly areas identified in 2006 coincide with the previous results. Increasing temperatures of the ground surface were recognized on the southeastern flank of the volcano in particular around Showa crater and fumarolic zones, over the data of 1992. In contrast, no significant change in the temperature was observed on the southern flank. These results suggest that the geothermal activity on the southeastern flank of the volcano became high prior to the 2006 eruption at Showa crater.