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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

Cubas, N. and Avouac, J. P. and Leroy, Y. M. and Pons, A. (2013) 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. Geophysical Research Letters, 40 (16). pp. 4231-4237. ISSN 0094-8276. http://resolver.caltech.edu/CaltechAUTHORS:20131113-094955566

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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.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1002/grl.50682DOIArticle
http://onlinelibrary.wiley.com/doi/10.1002/grl.50682/abstractPublisherArticle
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.
Group:Caltech Tectonics Observatory, Seismological Laboratory
Funders:
Funding AgencyGrant Number
NSFEAR-1118239
Gordon and Betty Moore FoundationGBMF 423.01
Subject Keywords:frictional properties; dynamic weakening; Tohoku-Oki earthquake; megathrust; splay fault; Coulomb wedge
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Other Numbering System NameOther Numbering System ID
Caltech Tectonics Observatory235
Record Number:CaltechAUTHORS:20131113-094955566
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20131113-094955566
Official Citation:Cubas, N., J. P. Avouac, Y. M. Leroy, and A. Pons (2013), 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, Geophys. Res. Lett., 40, 4231–4237, doi:10.1002/grl.50682.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:42419
Collection:CaltechAUTHORS
Deposited By: Jason Perez
Deposited On:13 Nov 2013 19:28
Last Modified:11 Jun 2015 13:57

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