Japan Geoscience Union Meeting 2016

Presentation information


Symbol M (Multidisciplinary and Interdisciplinary) » M-IS Intersection

[M-IS16] Drilling Earth Science

Thu. May 26, 2016 10:45 AM - 12:15 PM 103 (1F)

Convener:*Yasuhiro Yamada(Japan Agency for Marine-Earth Science and Technology (JAMSTEC), R&D Center for Ocean Drilling Science (ODS)), Minoru Ikehara(Center for Advanced Marine Core Research, Kochi University), Yusuke Suganuma(National institute of Polar Research), Kazuno Arai(Japan Agency for Marine-Earth Science and Technology), Keita Umetsu(Japan Agency for Marine Earth Science and Technology), Chair:Kazuya Shiraishi(Japan Agency for Marine-Earth Science and Technology), Saneatsu Saito(Japan Agency for Marine-Earth Science and Technology)

11:30 AM - 11:45 AM

[MIS16-10] JTRACK: Tracking Tsunamigenic Slips Across and Along the Japan Trench

*Shuichi Kodaira1, James C. Sample2, Michael Strasser3, Kohtaro Ujiie4, James David Kirkpatrick5, Patrick M. Fulton6, James J. Mori7 (1.R&D Center for Earthquake and Tsunami Japan Agency for Marine-Earth Science and Technology, 2.Northern Arizona University, 3.University of Innsbruck, 4.University of Tsukuba, 5.McGill University, 6.Texas A&M University, 7.Kyoto University)

Keywords:Japan Trench, Subduction, earthquake

Understanding the huge slip and associated devastating tsunami of the 2011 Tohoku-oki earthquake is a high priority challenge for IODP with important societal impacts. A primal objective of JTRACK is to define spatially-varying physical and chemical properties and conditions of the sediments and fluids of the near-trench megathrust that contribute to huge fault displacements and very large tsunamis. Following recommendations from the IODP Science Evaluation Panel and community input at the JTRACK Workshop (May 17-19, 2014, Tokyo), JTRACK focuses on the 2011 Tohoku-oki rupture zone by drilling two transects across the Japan Trench in regions of large and small coseismic slip. We will investigate the detailed geologic structures and rock properties of the fault zone, especially frictional and strength characteristics. Permeability and chemical studies will be used to infer the local hydrological structure and its effect on the earthquake rupture. Combining these observations and using comparisons of similar measurements for areas of high and low slip during the 2011 earthquake, we will try to infer key factors that control the amount of displacement during large earthquakes. In addition, time-dependent observations will be carried out to study fault healing after a large earthquake. These will focus on how the local hydrological and stress conditions change during the few years following the large fault displacement during the earthquake. Based on seismic images as well as associated geophysical data, the two 2-hole transects across the Japan Trench are selected in an area of large slip (>50 m) and smaller slip (1/3~1/2 of the large slip). Each transect has an ‘inner trench slope’ site mainly targeting the plate boundary fault zone, and an ‘input’ site seaward of the trench as a reference site.