JpGU-AGU Joint Meeting 2017

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[JJ] Oral

M (Multidisciplinary and Interdisciplinary) » M-IS Intersection

[M-IS22] [JJ] Drilling Earth Science

Thu. May 25, 2017 10:45 AM - 12:15 PM IC (International Conference Hall 2F)

convener:Yasuhiro Yamada(Japan Agency for Marine-Earth Science and Technology (JAMSTEC), R&D Center for Ocean Drilling Science (ODS)), Katsuyoshi Michibayashi(Institute of Geosciences, Shizuoka University), Minoru Ikehara(Center for Advanced Marine Core Research, Kochi University), Yusuke Suganuma(National institute of Polar Research), Chairperson:Katsuyoshi Michibayashi(Institute of Geosciences, Shizuoka University), Chairperson:Eiichi Takazawa(Niigata University)

11:15 AM - 11:30 AM

[MIS22-15] Tracking past earthquakes in the sediment record along the Japan Trench using giant piston coring: IODP proposal 866

*Ken Ikehara1, Toshiya Kanamatsu2, Kazuko Usami1, Michael Strasser3, proponents IODP Proposal 866 (1.Institute of Geology and Geoinformation, National Institute of Advanced Industrial Science and Technology, 2.Japan Agency of Marine Science and Technology, 3.University of Innsbruck)

Keywords:giant piston coring, Japan Trench, IODP

After the 2011 Tohoku-oki earthquake and its destructive tsunami, it is very important to understand the recurrence pattern of large earthquakes along the particular subduction area. Although onshore tsunami deposits provide a good recurrence record of huge tsunamis, the tsunami deposits might also reflect large far-field earthquakes and/or submarine landslides, and are useful only for the past few thousand years due to paleogeographic changes. Deep-sea event deposits (turbidites) deposited by earthquake-induced turbidity currents are a potential tool in the study of subaqueous paleoseismology. Previous studies in the central Japan Trench using conventional piston coring covering the last ~1500 years reveal good correlation between the deep-sea turbidite and onshore tsunami deposit record and historical documents. Furthermore, these studies also clarified the importance of surface sediment remobilization to generate earthquake-induced turbidity currents. Because sedimentary sequences in deep-sea environments are deposited in more stable conditions, intercalated event-deposits have a potential for understanding the recurrence pattern over long time-scale. The stratigraphic record of small trench-fill and graben-fill basins in the Japan Trench has great potential to record the past earthquake-related events. IODP proposal 866 proposes to obtain the long-term and complete record of large earthquakes along the Japan Trench, and to understand the impact of large earthquakes to sediment and carbon flux to the deep-sea environments.