Stress State in the Largest Displacement Area of the 2011 Tohoku-Oki Earthquake

Authors

Weiren Lin, Japan Agency for Marine-Earth Science and Technology
Marianne Conin, Centre Européen de Recherche et d'Enseignement des Géosciences de l'Environnement
Casey J. Moore, University of California - Santa Cruz
Frederick M. Chester, Texas A & M University - College Station
Yasuyuki Nakamura, Japan Agency for Marine-Earth Science and Technology
J Mori, Kyoto University
Louise Anderson, University of Leicester
Emily E. Brodsky, University of California - Santa Cruz
Nobuhisa Eguchi, Japan Agency for Marine-Earth Science and Technology

Abstract

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.

Department

Center for Coastal and Ocean Mapping

Publication Date

2-2013

Volume

339, Number 6120

Journal Title

Science

Pages

687–690

Publisher

American Association for the Advancement of Science (AAAS)

Digital Object Identifier (DOI)

10.1126/science.1229379

Document Type

Journal Article

Recommended Citation

W. Lin et al., "Stress state in the largest displacement area of the 2011 Tohoku-Oki earthquake," Science, vol. 339, no. 6120, pp. 687–690, Feb. 2013.