Japan Geoscience Union Meeting 2018

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[JJ] Oral

S (Solid Earth Sciences) » S-VC Volcanology

[S-VC41] Active Volcanism

Wed. May 23, 2018 10:45 AM - 12:15 PM Convention Hall A (CH-A) (2F International Conference Hall, Makuhari Messe)

convener:Yuta Maeda(Nagoya University), Takahiro Miwa(National research institute for earth science and disaster prevention), Yosuke Aoki(東京大学地震研究所, 共同), Takeshi Nishimura(Department of Geophysics, Graduate School of Science, Tohoku University), Takahiro Ohkura(Aso Volcanological Laboratory, Institute for Geothermal Sciences, Graduate School of Science, Kyoto University), Satoshi Okumura(Division of Earth and Planetary Materials Science, Department of Earth Science, Graduate School of Science, Tohoku University), Tomofumi Kozono(Department of Geophysics, Graduate School of Science, Tohoku University), Chairperson:Nagaoka Yutaka, Ozawa Taku

11:30 AM - 11:45 AM

[SVC41-46] Gravity signals around Shinmoe-dake volcano after its eruption in October 2017

*Shuhei Okubo1, Miwako Ando1 (1.Earthquake Research Institute, The University of Tokyo)

Keywords:Gravity, Shinmoe-dake volcano, Hybrid gravity measurement

Shinmoe-dake volcano started eruption on Oct. 11, 2017 and emitted at least several hundred thousands ton volcanic ash. In addition, daily emission of SO2 exceeded 10,000 ton on Oct. 15, 2017. Just after these events, we started gravity measurements around Shinmoe-dake to monitor subsurface transportation of magma. In this paper, we present our results of continuous absolute gravity measurement at Kirishima Volcano Observatory (KVO) and repeated hybrid gravity measurement on the route from KVO to Takachihogawara (3km south to Shinmoe-dake).
Absolute gravity at KVO exhibited rapid decrease of 10 microgals from Nov. 15 to Dec. 10, 2017 and remained virtually constant since then. The spatial pattern of the local gravity revealed 20 to 50 microgal decrease from Nov. 2017 to Feb. 2018.
We shall discuss how magma (or any mass) was transported during our observation period by considering the result of crustal deformation together.