Masato Iguchi, Surono, Takeshi Nishimura, Muhamad Hendrasto, Umar Rosadi, Takahiro Ohkura, Hetty Triastuty, Ahmad Basuki, Agoes Loeqman, Sukir Maryanto, Kazuhiro Ishihara, Mitsuhiro Yoshimoto, Setsuya Nakada, Natsumi Hokanishi
We report methods, based on geophysical observations and geological surveys, for the prediction of eruptions and the evaluation of the activity of 4 volcanoes in Indonesia. These are Semeru, Guntur, Kelud and Sinabung volcanoes. Minor increases in tilt were detected by borehole tiltmeters prior to eruptions at the Semeru volcano depending on the seismic amplitude of explosion earthquakes. The results show the possibility of prediction of the type and magnitude of eruption and the effectiveness of observation with a high signalto-noise ratio. The establishment of background data is important for evaluating volcanic activity in longterm prediction. Typical distributions of volcanic and local tectonic earthquakes were obtained around the Guntur volcano, where geodetic monitoring by continuous GPS observation is valuable. The cumulative volume of eruptive products is valuable for evaluating the potential for future eruption. The eruptive rate of the Kelud volcano is ca 2×106 m3/y (dense rock equivalent), but the volume of the 2007 eruption was only 2×107 m3, suggesting a still high potential for eruption. Based on geological surveys and dating, an eruption scenario is proposed for the activity of Mt. Sinabung, where phreatic eruptions occurred in 2010 after a historically long dormancy.
Disaster Prevention Research Institute, Kyoto University Sakurajima-Yokoyama, Kagoshima 891-1419, Japan; Center for Volcanology and Geological Hazard Mitigation Jl, Bandung 40122, Diponegoro 57, Indonesia; Graduate School of Science, Tohoku University, Japan; Graduate School of Science, Kyoto University, Japan; Faculty of Science, Brawijaya University, Indonesia; Graduate School of Science, School of Science Hokkaido University, Japan; Earthquake Research Institute, University of Tokyo, Japan
