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The 2010 M_W 6.8 Yushu (Qinghai, China) earthquake: constraints provided by InSAR and body wave seismology

Lookup NU author(s): Professor Zhenhong Li

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Abstract

By combining observations from satellite radar, body wave seismology and optical imagery, we have determined the fault segmentation and sequence of ruptures for the 2010 M_w 6.8 Yushu (China) earthquake. We have mapped the fault trace using displacements from SAR image matching, interferometric phase and coherence, and 2.5 m SPOT-5 satellite images. Modeling the event as an elastic dislocation with three segments fitted to the fault trace suggests that the southeast and northwest segments are near vertical, with the central segment dipping 70° to the southwest; slip occurs mainly in the upper 10 km, with a maximum slip of 1.5 m at a depth of 4 km on the southeastern segment. The maximum slip in the top 1 km (i.e., near surface) is up to 1.2 m, and inferred locations of significant surface rupture are consistent with displacements from SAR image matching and field observations. The radar interferograms show rupture over a distance of almost 80 km, much larger than initial seismological and field estimates of the length of the fault. Part of this difference can be attributed to slip on the northwestern segment of the fault being due to an M_w 6.1 aftershock two hours after the main event. The remaining difference can be explained by a non-uniform slip distribution with much of the moment release occurring at depths of less than 10 km. The rupture on the central and southeastern segments of the fault in the main shock propagated at a speed of 2.5 km/s southeastward toward the town of Yushu located at the end of this segment, accounting for the considerable building damage. Strain accumulation since the last earthquake on the fault segment beyond Yushu is equivalent to an M_w 6.5 earthquake.

Publication metadata

Author(s): Li Z, Elliott J, Feng W, Jackson J, Parsons B, Walters R

Publication type: Article

Publication status: Published

Journal: Journal of Geophysical Research: Solid Earth

Year: 2011

Volume: 116

Issue: B10

Print publication date: 04/10/2011

ISSN (print): 2169-9313

ISSN (electronic): 2169-9356

Publisher: Wiley-Blackwell

URL: http://dx.doi.org/10.1029/2011JB008358

DOI: 10.1029/2011JB008358

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