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Summary: The 2001 Mw 7.6 Bhuj earthquake, low fault friction,
and the crustal support of plate driving forces in India
Alex Copley,1,2
JeanPhilippe Avouac,1
James Hollingsworth,1
and Sébastien Leprince1
Received 1 December 2010; revised 19 May 2011; accepted 7 June 2011; published 19 August 2011.
[1] We present a source model for the 2001 Mw 7.6 Bhuj earthquake of northwest India.
The slip distribution suggests a high stress drop (35 MPa) and, together with the
depth distribution of aftershocks, that the entire crust is seismogenic. We suggest that the
active faults have an effective coefficient of friction of 0.08, which is sufficient for
the seismogenic crust to support the majority of the compressive force transmitted through
the Indian lithosphere. This model is consistent with the midcrustal depth of the transition
from extension to compression beneath the Ganges foreland basin where India
underthrusts southern Tibet. If the coefficient of friction were the more traditional value of
0.6, the lithosphere would be required to support a net force roughly an order of magnitude
higher than current estimates in order to match the observed depth of the neutral fiber.
Citation: Copley, A., J.P. Avouac, J. Hollingsworth, and S. Leprince (2011), The 2001 Mw 7.6 Bhuj earthquake, low fault
friction, and the crustal support of plate driving forces in India, J. Geophys. Res., 116, B08405, doi:10.1029/2010JB008137.
1. Introduction
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