Japan Geoscience Union Meeting 2018

Presentation information

[JJ] Poster

S (Solid Earth Sciences) » S-VC Volcanology

[S-VC41] Active Volcanism

Wed. May 23, 2018 1:45 PM - 3:15 PM Poster Hall (International Exhibition Hall7, 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)

[SVC41-P36] Exploration of S-wave velocity structure of Ogasawara Iwo-To Island

*Takumi Murakoshi1, Hideyuki Sasaki1, Shunta Asai1 (1.National Defense Academy)

Keywords:Ogasawara Iwo-To Island, S-wave velocity structure, subsurface structure, microtremor

Ogasawara Iwo-To island is an active volcanic island which is located on the southernmost part of Izu-Ogasawara arc. Microtremors have been observed at two sites in the Ogasawara Iwo-To island, through observations performed on October 6-9, 2017, in order to investigate 1-D S-wave velocity structures. The circular-array microtremor data were recorded by 3 seismometers distributed along the circumferences of circle as well as a seismometer deployed in the center at two sites. Each microtremor observation site includes two arrays with different radii. The maximum radii of the eqilateral triangles are 400m for the western site and 1240m for the nortern site in the Ogasawara Iwo-To island. The phase velocities and the S-wave velocities of the subsurface structures down to a depth of several km were estimated at each site from the microtremor data by using the SPAC method.

This study was supported by the Earthquake Research Institute cooperative research program.