The postearthquake stress state on the Tohoku megathrust as constrained by reanalysis of the JFAST breakout data

Emily E. Brodsky, Demian Saffer, Patrick Fulton, Frederick Chester, Marianne Conin, Katelyn Huffman, J. Casey Moore, Hung Yu Wu

Research output: Contribution to journalArticle

8 Scopus citations

Abstract

The Japan Trench Fast Drilling Project (JFAST) endeavored to establish the stress state on the shallow subduction megathrust that slipped during the M9 Tohoku earthquake. Borehole breakout data from the drill hole can constrain both the orientation and magnitude of the principal stresses. Here we reanalyze those data to refine our understanding of the stress state on the fault. In particular, we (1) improve the identification of breakouts, (2) consider a fuller range of stress states consistent with the data, and (3) incorporate new and more robust laboratory constraints on rock strength. The original conclusion that the region is in a normal faulting regime after the earthquake is strengthened by the new analysis. The combined analysis suggests that the earthquake released sufficient elastic strain energy to reset the local stress field.

Original languageEnglish (US)
Pages (from-to)8294-8302
Number of pages9
JournalGeophysical Research Letters
Volume44
Issue number16
DOIs
StatePublished - Aug 28 2017

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Earth and Planetary Sciences(all)

Fingerprint Dive into the research topics of 'The postearthquake stress state on the Tohoku megathrust as constrained by reanalysis of the JFAST breakout data'. Together they form a unique fingerprint.

  • Cite this