Low friction along the high slip patch of the 2011 Mw 9.0 Tohoku-Oki earthquake required from the wedge structure and extensional splay faults
- Creators
- Cubas, N.
- Avouac, J. P.
- Leroy, Y. M.
- Pons, A.
Abstract
We analyze the mechanical properties needed to account for the large shallow slip during the 2011 Tohoku-Oki earthquake and the activation of landward normal faulting within the forearc. We show that the morphology and internal structure of the forearc follows closely the prediction of the critical Coulomb wedge in horizontal compression, implying a high internal pore pressure ratio (λ = 0.7 + 0.14/ – 0.48) and a low effective basal friction (μ^(eff)_b = 0.14 + 0.18/ – 0.04). We then show that the activation of the normal fault requires a lower effective basal friction beneath the outer wedge than beneath the inner wedge (μ_outer ≤ 0.015), possibly due to transient dynamic weakening associated to the seismic rupture. Forearc normal faults could be considered as evidence for very efficient dynamic weakening along the megathrust and typify megathrust with high tsunamigenic potential.
Additional Information
© 2013 American Geophysical Union. Received 28 May 2013; revised 18 June 2013; accepted 18 June 2013; published 27 August 2013. This project was supported by the National Science Foundation through grant EAR-1118239 and by the Gordon and Betty Moore Foundation through grant GBMF 423.01 to the Caltech Tectonics Observatory. This is Tectonics Observatory contribution # 235. The Editor thanks two anonymous reviewers for their assistance in evaluating this paper.Attached Files
Published - grl50682.pdf
Supplemental Material - README.rtf
Supplemental Material - text01.pdf
Supplemental Material - ts01.pdf
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Additional details
- Eprint ID
- 42419
- Resolver ID
- CaltechAUTHORS:20131113-094955566
- EAR-1118239
- NSF
- GBMF 423.01
- Gordon and Betty Moore Foundation
- Created
-
2013-11-13Created from EPrint's datestamp field
- Updated
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2021-11-10Created from EPrint's last_modified field
- Caltech groups
- Caltech Tectonics Observatory, Seismological Laboratory, Division of Geological and Planetary Sciences
- Other Numbering System Name
- Caltech Tectonics Observatory
- Other Numbering System Identifier
- 235