JpGU-AGU Joint Meeting 2017

講演情報

[EE] ポスター発表

セッション記号 S (固体地球科学) » S-SS 地震学

[S-SS04] [EE] Subduction zone dynamics from regular earthquakes through slow earthquakes to creep

2017年5月24日(水) 15:30 〜 17:00 ポスター会場 (国際展示場 7ホール)

コンビーナ:金川 久一(千葉大学大学院理学研究科)、小原 一成(東京大学地震研究所)、Demian M Saffer(Pennsylvania State University)、Wallace Laura(University of Texas Institute for Geophysics)

[SSS04-P40] Large-scale electrical resistivity structure around the long-term Slow Slip Events beneath the Bungo Channel region, southwest Japan

*吉村 令慧1山崎 健一1小川 康雄2中川 潤1川崎 慎吾1小松 信太郎1米田 格1大内 悠平3岡崎 智久3鈴木 惇史4齋藤 全史郎4臼井 嘉哉4寺石 眞弘1 (1.京都大学防災研究所、2.東京工業大学理学院火山流体研究センター、3.京都大学大学院理学研究科、4.東京工業大学理工学研究科)

キーワード:slow slip events, Bungo Channel, resistivity structure

Recent geodetic observations detect recurrent slow slip events (SSEs), which occurred beneath the Bungo Channel and southwest Shikoku Island, with interval of approximately 6 years (e.g. GSI, 2010). In order to reveal a large-scale three-dimensional resistivity structure around SSEs region, we carried out wideband magnetotelluric (MT) surveys around the western part of Shikoku Island. We also plan to establish a permanent long-term MT monitoring network that aims to detect temporal changes of resistivity structure during SSE cycle. As of June, 2016, MT surveys were performed at 31 sites by using Phoenix wideband MT instruments. In the most of sites, high quality MT responses were obtained using the BIRRP code (Chave and Thomson, 2004) for the period range 300 Hz to 10,000 sec. The spatial distributions of the phase tensor ellipses and the induction vectors suggest that resistivity contrasts are located surrounding SSEs. In this presentation, we show the results of the data analysis and preliminary inverted three-dimensional model around the transition zone between SSEs and stick-slip regions.