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

Weiren Lin and Marianne Conin and J. C. Moore and Frederick M. Chester and Yasuyuki Nakamura and James J. Mori and Louise Anderson and Emily E. Brodsky and Nobuhisa Eguchi and Expedition 343 Scientists. ( 2013 )
in: Science, 339:6120 (687-690)

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.

Download / Links

BibTeX Reference

@ARTICLE{Lin et al,
    author = { Lin, Weiren and Conin, Marianne and Moore, J. C. and Chester, Frederick M. and Nakamura, Yasuyuki and Mori, James J. and Anderson, Louise and Brodsky, Emily E. and Eguchi, Nobuhisa and Scientists, Expedition 343 },
     title = { Stress State in the Largest Displacement Area of the 2011 Tohoku-Oki Earthquake },
   journal = { Science },
    volume = { 339 },
    number = { 6120 },
      year = { 2013 },
     pages = { 687-690 },
       url = { http://www.sciencemag.org/content/339/6120/687.abstract },
       doi = { 10.1126/science.1229379 },
  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. }
}