Stress state in the largest displacement area of the 2011 Tohoku-Oki earthquake

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doi: 10.1126/science.1229379
Author(s): Lin, Weiren; Conin, Marianne; Moore, J. Casey; Chester, Frederick M.; Nakamura, Yasuyuki; Mori, James J.; Anderson, Louise; Brodsky, Emily E.; Eguchi, Nobuhisa
Integrated Ocean Drilling Program, Expedition 343 Scientists, College Station, TX
Author Affiliation(s): Primary:
Japan Agency for Marine-Earth Science and Technology, Kochi Institute for Core Sample Research, Nankoku, Japan
Centre Européen de Recherche et d'Enseignement des Géosciences de l'Environnement, France
University of California at Santa Cruz, United States
Texas A&M University, United States
Kyoto University, Japan
University of Leicester, United Kingdom
Volume Title: Science
Source: Science, 339(6120), p.687-690. Publisher: American Association for the Advancement of Science, Washington, DC, United States. ISSN: 0036-8075 CODEN: SCIEAS
Note: In English. 33 refs.; illus., incl. sect., sketch map
Summary: The 2011 moment magnitude 9.0 Tohoku-Oki earthquake produced a maximum coseismic slip of more than 50 meters near the Japan trench, which could result in a completely reduced stress state in the region. We tested this hypothesis by determining the in situ stress state of the frontal prism from boreholes drilled by the Integrated Ocean Drilling Program approximately 1 year after the earthquake and by inferring the pre-earthquake stress state. On the basis of the horizontal stress orientations and magnitudes estimated from borehole breakouts and the increase in coseismic displacement during propagation of the rupture to the trench axis, in situ horizontal stress decreased during the earthquake. The stress change suggests an active slip of the frontal plate interface, which is consistent with coseismic fault weakening and a nearly total stress drop.
Year of Publication: 2013
Research Program: IODP Integrated Ocean Drilling Program
ODP Ocean Drilling Program
Key Words: 16 Structural Geology; 19 Geophysics, Seismology; Active faults; Coseismic processes; Displacements; Earthquakes; Expedition 343; Faults; IODP Site C0019; Integrated Ocean Drilling Program; Japan Trench; Japan Trench Fast Drilling Project; Leg 186; Neotectonics; North Pacific; Northwest Pacific; ODP Site 1150; ODP Site 1151; Ocean Drilling Program; Pacific Ocean; Stress; Stress drops; Tectonics; Tohoku-Oki earthquake 2011; West Pacific
Coordinates: N380000 N390000 E1440000 E1420000
Record ID: 2013030551
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