Bollinger, L. and Avouac, J. P. and Cattin, R. and Pandey, M. R. (2004) Stress buildup in the Himalaya. Journal of Geophysical Research B, 109 (B11). Art. No. B11405. ISSN 0148-0227 http://resolver.caltech.edu/CaltechAUTHORS:20101118-132506328
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The seismic cycle on a major fault involves long periods of elastic strain and stress accumulation, driven by aseismic ductile deformation at depth, ultimately released by sudden fault slip events. Coseismic slip distributions are generally heterogeneous with most of the energy being released in the rupture of asperities. Since, on the long term, the fault's walls generally do not accumulate any significant permanent deformation, interseismic deformation might be heterogeneous, revealing zones of focused stress buildup. The pattern of current deformation along the Himalayan arc, which is known to produce recurring devastating earthquakes, and where several seismic gaps have long been recognized, might accordingly show significant lateral variations, providing a possible explanation for the uneven microseismic activity along the Himalayan arc. By contrast, the geodetic measurements show a rather uniform pattern of interseismic strain, oriented consistently with long-term geological deformation, as indicated from stretching lineation. We show that the geodetic data and seismicity distribution are reconciled from a model in which microseismicity is interpreted as driven by stress buildup increase in the interseismic period. The uneven seismicity pattern is shown to reflect the impact of the topography on the stress field, indicating low deviatoric stresses (<35 MPa) and a low friction (<0.3) on the Main Himalayan Thrust. Arc-normal thrusting along the Himalayan front and east-west extension in southern Tibet are quantitatively reconciled by the model.
|Additional Information:||© 2004 American Geophysical Union. Received 26 November 2003; revised 16 July 2004; accepted 5 August 2004; published 20 November 2004. We are most grateful to Yehuda Bock, Roger Bilham, and Jeffrey Freymueller for their comments and suggestions, which greatly helped improve this manuscript. This is Caltech Tectonics Observatory contribution number 8.|
|Group:||Caltech Tectonics Observatory, Caltech Tectonics Observatory. Indo-Asian Collision Zone|
|Subject Keywords:||seismic cycle; interseismic; microseismicity; geodesy; Himalaya; Nepal|
|Other Numbering System:|
|Official Citation:||Bollinger, L., J. P. Avouac, R. Cattin, and M. R. Pandey (2004), Stress buildup in the Himalaya, J. Geophys. Res., 109, B11405, doi:10.1029/2003JB002911|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Tony Diaz|
|Deposited On:||18 Nov 2010 21:42|
|Last Modified:||26 Dec 2012 12:39|
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