Evaluation of Volcanic Activity at Sinabung Volcano, After More Than 400 Years of Quiet
Muhamad Hendrasto*1, Surono*1, Agus Budianto1,
Kristianto*1, Hetty Triastuty*1, Nia Haerani*1,
Ahmad Basuki*1, Yasa Suparman*1,
Sofyan Primulyana*1, Oktory Prambada*1,
Agoes Loeqman*1, Novianti Indrastuti*1,
Aditya Sebastian Andreas*1, Umar Rosadi*1,
Sucahyo Adi*1, Masato Iguchi*2,
Takahiro Ohkura*3, Setsuya Nakada*4,
and Mitsuhiro Yoshimoto*5
*1Center for Volcanology and Geological Hazard Mitigation, Geological Agency, Ministry of Energy and Mineral Resources, Indonesia, Jalan Diponegoro No.57, Bandung 40122, West Java, Indonesia
*2Sakurajima Volcano Research Center, Disaster Prevention Research Institute, Kyoto University, Japan
*3Aso Volcano Observatory, Kyoto University, Japan
*4Earthquake Research Institute, University of Tokyo, Japan
*5Hokkaido University, Japan
Before its 2010 eruption, Sinabung Volcano was a Btype volcano, in its Indonesian classification. A series of explosions featuring 1-5 km high phreatic-ash columns occurred from August 27, 2010 untill September 7, 2010. SO2 flux measured during the eruptions showed sizeable gas emission and the youngest volcanic product has age of 1200 years BP obtained from 14C dating. At the end of August 2010, four continuous seismic stations were established around the volcano, and 6 additional stations were deployed in October 2010. Deformation monitoring was conducted temporarily till in February 2011, four continuous GPS stations were installed. All were set up through collaboration between Indonesian and Japanese academic and government institutions. Hypocenter calculations using data of 4 seismic stations fromSeptember to October 2010 showed two concentrations for shallow volcanic earthquakes (VTB) 0.5-2 km beneath the crater and for deep volcanic earthquakes (VTA) 2.5-14 km beneath the crater. These epicenters defined a northeast-southwest lineament, near an elongated sinistral fault zone between Sinabung and Sibayak volcanoes. Earthquake sources went deeper northeastward. Results using the data of 10 stations from November 2010 to February 2011 showed that earthquakes were concentrated at depths of 4-6 km beneath Lake Lau Kawar. Tilt and Electro-optic Distance Measurement (EDM) measurements from August to September 2010 showed no significant changes We inferred that since the last explosion in 7 September 2010, stabilization process both in pressure and energy were low.
Kristianto, H. Triastuty, N. Haerani, <. Basuki, Y. Suparman, <. Primulyana, O. Prambada, <. Loeqman, N. Indrastuti, <. Andreas, U. Rosadi, <. Adi, M. Iguchi, <. Ohkura, S. Nakada, and <. Yoshimoto, “Evaluation of Volcanic Activity at Sinabung Volcano, After More Than 400 Years of Quiet,” J. Disaster Res., Vol.7, No.1, pp. 37-47, 2012.
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