Japan Geoscience Union Meeting 2021

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S (Solid Earth Sciences ) » S-EM Earth's Electromagnetism

[S-EM12] Electric, magnetic, and electromagnetic survey technologies and the scientific achievements

Thu. Jun 3, 2021 5:15 PM - 6:30 PM Ch.11

convener:Kiyoshi Baba(Earthquake Research Institute, The University of Tokyo), Tada-nori Goto(Graduate School of Life Science, University of Hyogo), Toshihiro Uchida(National Institute of Advanced Industrial Science and Technology), Yuguo Li(Ocean University of China)

5:15 PM - 6:30 PM

[SEM12-P02] Three-dimensional inversion of magnetotelluric data in a geothermal area near Hakkoda volcano

*Toshihiro Uchida1 (1.National Institute of Advanced Industrial Science and Technology)

Keywords:magnetotellurics, 3D inversion, topography, geothermal exploration

Three-dimensional (3D) inversion was carried out to a magnetotelluric (MT) dataset obtained in a geothermal area on a western flank of northern Hakkoda volcano, Aomori Prefecture, Japan. The 3D inversion code used is WSINV3DMT (Siripunvaraporn and Egbert, 2009). The number of MT stations is 34, and the number of frequencies used as observed data in the inversion is 15, ranging from 0.0067 Hz to 115 Hz. The surface topography was included in the finite-difference mesh with a small vertical discretization in order to achieve accurate forward modeling. The size of a cell at the ground surface for the elevation range where the MT stations are located was set to 150m x 150m x 10m, basically. The resultant 3D model indicated a good correlation with logging data in a few boreholes obtained in the surveys about 30 years ago. The procedure of the 3D inversion and geothermal interpretation of the model are presented in this paper.