3:30 PM - 4:30 PM
[J08-P-06] Deep Conductive Structure beneath the Kutcharo Caldera, Revealed by 3-D Inversion Analysis
○Ryo Honda1, Hiroshi Ichihara2, Yusuke Yamaya3, Hideaki Hase4, Toru Mogi5, Makoto Uyeshima6, Mitsuhiro Nakagawa7 (1.Mount Fuji Research Institute, Yamanashi, Japan, 2.Kobe Ocean Bottom Exploration Center (KOBEC), Kobe Univ., Kobe, Japan, 3.Fukushima Renewable Energy Institute, AIST, Fukushima, Japan, 4.Geothermal Energy Research & Development Co., Ltd., Tokyo, Japan, 5.Faculty of Engineering, Hokkaido Univ., Hokkaido, Japan, 6.Earthquake Research Institute, University of Tokyo, Tokyo, Japan, 7.Graduate School of Science, Hokkaido Univ., Hokkaido, Japan)
Our survey was executed by wide-band and the long-period observations during 2009 and 2010. With our survey data, we compiled the wide-band MT data from Ichihara et al. (2009, EPS) and Ichihara et al. (2013, Tectonophys.), which are the observation data around the focal area of Teshikaga Earthquake. We adopted the remote reference analyses (Gamble et al., 1978, Geophysics) to these MT data. We used the reference magnetic data of Kakioka Magnetic Observatory and the Esashi station for the long wavelength and the wide-band data, respectively.
The three dimensional analysis is executed by WSINV3DMT (Siripunvaraporn et al., 2005, PEPI; Siripunvaraporn et al., 2009, PEPI). The characteristic resistivity structures found in the result is almost consistent with the result of the 2-D analyses (Honda et al., 2011). The extraordinary low resistivity body piercing the high resistivity layer towards the Atosanupri volcano from the deep layer was remarkable in the 2-D result. By the 3-D analysis, the conductor under the Kutcharo caldera became sharp.
Acknowledgement
For this study, we have used the computer systems of the Earthquake and Volcano Information Center of the Earthquake Research Institute, the University of Tokyo. We are thankful for the magnetic data provided by the GSI and JMA.