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| Rupture pattern of the Oct 23, 2011 Van-Merkez, Eastern Turkey earthquake |
| Hao Zhang1,2, Zengxi Ge1 |
1 Department of Geophysics, School of Earth and Space Sciences, Peking University, Beijing 100871, China
2 Department of Earth and Planetary Sciences, Northwestern University, 2145 Sheridan Rd, Evanston, IL 60208, USA |
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Abstract High-frequency rupture process of the Oct 23, 2011 Van-Merkez earthquake is imaged by back-projection method using high-quality teleseismic P wave data from the US Array, and prestack Kirchhoff migration using P wave data from a subarray of global seismic networks. The rupture model with two asperities is confirmed by previous two methods. In low-frequency imaging, a large asperity derived from the migration method corresponds to the second one from the high-frequency P waves. The consistency of the locations of asperities from datasets with different frequency bands indicates that there is possible insignificance of the frequency-dependent feature for the earthquake. The resultant images illustrate the spatial and temporal evolution of the rupture, which mainly propagated WSW over a length of 33 km during the first 18 s, accompanying with bursts of two asperities at 3 and 11–13 s. The rupture direction is confirmed by the S wave corner frequency variations of strong ground accelerations. The rupture fronts are mainly located at the updip of the causative fault. Based on polarities of the P waveforms and focal mechanisms of the mainshock and aftershocks, the failure of these two asperities is determined to have occurred on a reverse fault with a dip angle of 47°. Hence, the rupture pattern of the 2011 Van-Merkez earthquake was dominated by a unilateral rupture toward the westsouthwest direction.
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Received: 26 December 2013
Published: 14 March 2014
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| Fund:the National Science Natural Foundation of China (Grant Nos. 41074029, 40821160552 and 40821062) |
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Corresponding Authors:
Zengxi Ge
E-mail: zge@pku.edu.cn
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