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Estimation of slip distribution for the Mw7.8 Kunlunshan earthquake by coseismic displacements
Received date: 2014-10-13
Revised date: 2015-04-03
Online published: 2015-09-15
The Mw7.8 Kunlunshan earthquake of November 14,2001, which ruptured over a total distance of about 400 km, was characterized by a 350-km-long main fault with an east-ward-propagating pulse of left-lateral slip. The field observations of coseismic displacement along the main fault provide us a good opportunity to study the earthquake source mechanism and fault geometry inside the earth. In this paper, based on Freund's III-dislocation model and constrained by two groups of surface rupture data from field investigation and geodetic measurement, we invert the slip distribution, the variation of static stress drop on the fault surface, and the fault width extending at depth along the fault strike-slip direction. The pattern of slip distribution on the fault surface deduced from the III-dislocation model is very similar to the result of the finite-fault solution based on the teleseismic body-wave inversion, showing that both slip distributions appear intensively heterogeneous in the special domain. The fault rupture width is much less than 20 km. These results also imply that the coseismic displacement along the fault strike direction on the earth surface is proportional to the fault width. In addition we also calculate the static stress change on the fault based on the III-dislocation model and slip distribution by teleseismic inversion. The analytical and numerical results show that they have high-level consistency.
MI Qi , LI Yanheng , SHEN Wenhao , SHI Baoping . Estimation of slip distribution for the Mw7.8 Kunlunshan earthquake by coseismic displacements[J]. Journal of University of Chinese Academy of Sciences, 2015 , 32(5) : 652 -660 . DOI: 10.7523/j.issn.2095-6134.2015.05.011
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