RELOCATION OF MAIN SHOCK AND AFTERSHOCKS OF THE 2014 YINGJIANG MS5.6 AND MS6.1 EARTHQUAKES IN YUNNAN |
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Authors: | YANG Ting WU Jian-ping FANG Li-hua WANG Wei-lai |
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Institution: | Institute of Geophysics, China Earthquake Administration, Beijing 100081, China |
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Abstract: | Yingjiang area is located in the China-Burma border,the Sudian-Xima arc tectonic belt,which lies in the collision zone between the Indian and Eurasian plates.The Yingjiang earthquake occurring on May 30th,2014 is the only event above MS6.0 in this region since seismicity can be recorded.In this study,we relocated the Yingjiang MS5.6 and MS6.1 earthquake sequences by using the double-difference method.The results show that two main shocks are located in the east of the Kachang-Dazhuzhai Fault,the northern segment of the Sudian-Xima Fault.Compared with the Yingjiang MS5.6 earthquake,the Yingjiang MS6.1 earthquake is nearer to the Kachang-Dazhuzhai Fault.The aftershocks of the two earthquakes are distributed along the strike direction of the Kachang-Dazhuzhai Fault (NNE).The rupture zone of the main shock of Yingjiang MS6.1 earthquake extends northward approximately 5km.The aftershocks of two earthquakes are mainly located in the eastern side of the Kachang-Dazhuzhai Fault with a significant asymmetry along the fault,which differ from the characteristics of the aftershock distribution of the strike-slip earthquake.It may indicate that the Yingjiang earthquakes are conjugate rupture earthquakes.The non-double-couple components are relatively high in the moment tensor.We speculate that the Yingjiang earthquakes are related to the fractured zone caused by the long-term seismic activity and heat effect in the deep between Kachang-Dazhuzhai Fault and its neighboring secondary faults.Aftershock distribution of the Yingjiang MS6.1 earthquake on the southern area crosses a secondary fault on the right of the Kachang-Dazhuzhai Fault,suggesting that the coseismic rupture of the secondary fault may be triggered by the dynamic stress of the main shock. |
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Keywords: | Yingjiang earthquake Sudian-Xima arc tectonic zone Kachang-Dazhuzhai Fault aftershock sequences double-difference relocation |
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