Researcher Information

MURAI Yoshio

Associate Professor

Investigation of subsurface structure and seismicity in offshore areas

Institute of Seismology and Volcanology, Ocean Bottom Seismology and Tsunami

basic_photo_1
Theme

Structural exploration and seismic observation by use of the ocean bottom seismographs in offshore areas toward clarification of the relationship between earthquake occurrence and subsurface structure
Theoretical study on elastic wave propagation in heterogeneous media

FieldOcean bottom seismology, Structure of the earth interior, Tectonics, Elastic wave propagation theory
KeywordOcean bottom seismograph (OBS), Seismic survey, Seismic tomography, Heterogeneous structure

Introduction of Research

Most of the destructive earthquakes around Japan have occurred beneath the sea floor. We carry out structural exploration and seismic observation by use of the ocean bottom seismographs in offshore areas in order to clarify the relationship between earthquake occurrence and subsurface structure. Seismic tomographic analysis using data from a dense network of OBSs and land stations enables us to estimate the subsurface structure of both onshore and offshore areas in the southern Hokkaido. Here we present an arc-arc collision structure in Figure: P wave velocity structure of the Hidaka collision zone. Moreover various geophysical studies have been conducted in the Atlantic area mainly in Mid-Atlantic Ridges (Figure: The Atlantic transect from East Greenland to the Norwegian mainland).

study-image-0
P wave velocity structure of the Hidaka collision zone
study-image-1
The Atlantic transect from East Greenland to the Norwegian mainland

Representative Achievements

Crustal composition of the Møre Margin and compilation of a conjugate Atlantic margin transect, T. Kvarven, R. Mjelde, B. O. Hjelstuen, J. I. Faleide, H. Thybo, E. R. Flueh and Y. Murai, Tectonophysics, 2016, 666, 144-157.
Was the 1952 Tokachi-oki earthquake (Mw=8.1) a typical underthrust earthquake?: Plate interface reflectivity measurement by an air gun - ocean bottom seismometer experiment in the Kuril Trench, R. Azuma, Y. Murai, K. Katsumata, Y. Nishimura, T. Yamada, K. Mochizuki and M. Shinohara, Geochemistry Geophysics Geosystems, 2012, 13(8), Q08015.
Heterogeneous structure around the rupture area of the 2003 Tokachi-oki earthquake (Mw=8.0), Japan, as revealed by aftershock observations using Ocean Bottom Seismometers, Y. Machida, M. Shinohara, T. Takanami, Y. Murai, T. Yamada, N. Hirata, K. Suyehiro, T. Kanazawa, Y. Kaneda, H. Mikada, S. Sakai, T. Watanabe, K. Uehira, N. Takahashi, M. Nishino, K. Mochizuki, T. Sato, E. Araki, R. Hino, K. Uhira, H. Shiobara and H. Shimizu, Tectonophysics, 2009, 465, 164-176.
Scattering attenuation, dispersion and reflection of SH waves in 2-D elastic media with densely distributed cracks, Y. Murai, Geophysical Journal International, 2007, 168, 211-223.
Delamination structure imaged in the source area of the 1982 Urakawa-oki earthquake, Y. Murai, S. Akiyama, K. Katsumata, T. Takanami, T. Yamashina, T. Watanabe, I. Cho, M. Tanaka, A. Kuwano, N. Wada, H. Shimamura, I. Furuya, D. Zhao and R. Sanda, Geophysical Research Letters, 2003, 30.
Academic degreeDoctor of Science
Academic background1989 Graduated. Faculty of Science, Kyoto University
1991 Master course finished. Graduate School of Science, Kyoto University
1995 Doctoral course finished. Graduate School of Science, University of Tokyo
1995-1997 Technical officer, Japan Meteorological Agency
1997-1998 Research Associate, Laboratory for Ocean Bottom Seismology, Faculty of Science, Hokkaido University
1998-2006 Research Associate, Institute of Seismology and Volcanology, Graduate School of Science, Hokkaido University
2006-2007 Research Associate, Institute of Seismology and Volcanology, Faculty of Science, Hokkaido University
2007-2009 Assistant Professor, Institute of Seismology and Volcanology, Faculty of Science, Hokkaido University
2009-Present Associate Professor, Institute of Seismology and Volcanology, Faculty of Science, Hokkaido University
Affiliated academic societyThe Seismological Society of Japan, Japan Geoscience Union, American Geophysical Union
Room addressFaculty of Science Building 4 4-215