Japan Geoscience Union Meeting 2014

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Oral

Symbol S (Solid Earth Sciences) » S-CG Complex & General

[S-CG67_2AM1] Ocean Floor Geoscience

Fri. May 2, 2014 9:00 AM - 10:45 AM 418 (4F)

Convener:*Kyoko Okino(Ocean Research Institute, University of Tokyo), Keiichi Tadokoro(Research Center for Seismology, Volcanology and Earthquake and Volcano Research Center, Nagoya University), Osamu Ishizuka(Institute of Geoscience, Geological Survey of Japan/AIST), Tomohiro Toki(Faculty of Science, University of the Ryukyus), Narumi Takahashi(Earthquake and Tsunami Research Project for Disaster Prevention, Japan Agency for Marine-Earth Science and Technology), Chair:Yukihito Osada(Research Center for Prediction of Earthquakes and Volcanic Eruptions, Graduate School of Science, Tohoku University), Yusuke Yokota(Japan Coast Guard, Hydrographic and oceanographic department)

10:00 AM - 10:15 AM

[SCG67-15] Understanding recoupling process using a seafloor geodesy in megathrust earthquake zone

*Yukihito OSADA1, Yoshihiro ITO2, Motoyuki KIDO1, Ryota HINO1, Takeshi IINUMA1 (1.IRiDes, Tohoku University, 2.DPRI, Kyoto Uniersity)

Keywords:seafloor crustal movement, Japan Trench

The 11 March 2011 Tohoku-Oki earthquake ruptured the interplate boundary off the eastern shore Honshu, generated a devastating tsunami that swept the coastal area along the northeastern Japan. The seafloor geodesy brought important results that showthat the large slip was near the Japan Trench and suggested the heterogeneity of the coseismic slip distribution in the plate interface. The maximum displacement region for interplate earthquake is mainly located offshore region. Therefore it is important to monitor the postseismic displacement and the stress accumulation process using seafloor geodesy. And if we can observe the postseismic displacement near the Japan Trench, we contribute to understand the coupling condition of plate boundary. There is a seafloor acoustic ranging system for direct observation of horizontal displacement on seafloor. We improve this system that adapted for the axis of Japan Trench. The system is designed to measure distances of up to 3 km and to adapt the pressure vesselof 9000m water-depth. We deployed the seafloor acoustic ranging system between 2013 May and 2013 Sep. We observed across the Tranch baseline (about 7km), baseline between the bottom of Tranch to the seaward side of Japan Trench (about 3.6km). We get data both baseline results for 4 month. We report this results on this presentation.