open access

https://hdl.handle.net/2115/80704

Cohesional Slip on a Plate Subduction Boundary During a Large Earthquake

英語

cohesion

2020-09-28

American Geophysical Union

Geophysical research letters

47(18)

e2020GL088395

The frontal part of the Japan Trench plate boundary fault, which slipped during the 2011 Tohoku-Oki earthquake (M(w)9.0), is enriched in smectite and is intrinsically weak owing to the high swelling pressure of this mineral. Our rheometric experiments using analog fault materials demonstrate that "cohesional slip," rather than frictional slip, is a realistic faulting process in the studied fault zone. The cohesional slip can be described by the Bingham plastic model. Consequently, the coseismic shear stress is described by the yield stress and plastic viscosity. Comparison of the results with the average shear stress derived from a previous study suggests that the slip zone thickness for cohesional slip is similar to 1.3 cm or less. This finding is consistent with textures characterized by discrete slip planes of comparable thickness observed in the recovered fault rocks, suggesting that these slip planes were activated during the Tohoku-Oki earthquake.

学術雑誌論文

Accepted Manuscript

Copyright (2020) American Geophysical Union.

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