Japan Geoscience Union Meeting 2016

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International Session (Poster)

Symbol S (Solid Earth Sciences) » S-SS Seismology

[S-SS02] Frontier studies on subduction zone megathrust earthquakes and tsunamis

Tue. May 24, 2016 5:15 PM - 6:30 PM Poster Hall (International Exhibition Hall HALL6)

Convener:*Kyuichi Kanagawa(Graduate School of Science, Chiba University), Demian Saffer(Department of Geosciences, The Pennsylvania State University, USA), Michael Strasser(University of Innsbruck), James Kirkpatrick(McGill University), Shuichi Kodaira(R&D Center for Earthquake and Tsunami Japan Agency for Marine-Earth Science and Technology), Ryota Hino(Graduate School of Science, Tohoku University), Yasuhiro Yamada(Japan Agency for Marine-Earth Science and Technology (JAMSTEC), R&D Center for Ocean Drilling Science (ODS)), Kohtaro Ujiie(Graduate School of Life and Environmental Sciences, University of Tsukuba), Yoshihiro Ito(Disaster Prevention Research Institute, Kyoto University)

5:15 PM - 6:30 PM

[SSS02-P17] Determination of slip parameters of subduction earthquake by using multiple analyses of carbonaceous materials

*Shunya Kaneki1, Tetsuro Hirono1, Hideki Mukoyoshi2, Yoshikazu Sampei2, Minoru Ikehara3 (1.Graduate School of Science, Osaka University, 2.Interdisciplinary Graduate School of Science and Engineering, Shimane University, 3.Center for Advanced Marine Core Research, Kochi University)

Keywords:carbonaceous materials, frictional heat, spectrometry, elemental analysis, slip parameters

Megasplay faults branching from megathrusts could play an important role in faulting systems in the plate-subduction zone. Because not only subduction megathrust but also megasplay faults could slip during an earthquake, possibly generating gigatic tsunami.
For understanding the slip behavior of these faults, maximum temperature recorded is one of the keys to estimate the slip parameters such as shear stress and displacement of the earthquake. Here we develop new multiple analyses to detect the heat signal recorded in the carbonaceous materials by performing heating experiments, spectroscopic analyses (IR and Raman), and chemical composition analysis (CHNSO element analysis). We targeted the carbonaceous materials retrieved from an ancient megasplay fault developed in the late Cretaceous Shimanto accretionary prism, southwest Japan.
Our results revealed that the fault zone had experienced 400–600 °C. By performing numerical temperature calculation, we found that any case of the earthquake events always accompany a slip displacement of ≤10 m, suggesting that several hundreds of events repeatedly took place.