Relocation of earthquakes in North China using absolute and relative earthquake relocation methods

doi:10.7523/j.issn.2095-6134.2015.02.014

Abstract

Abstract:

We relocated 17 315 earthquakes totally which occurred in North China (110°-120°E, 35°-42°N) during the periods between 1993 and 2004 and between 2007 and 2012 by using both absolute and relative earthquake relocation methods with waveform cross-correlation. Finally we got hypocenter parameters of 11 453 earthquakes. The distribution of epicenter relocation gives a linear band pattern with NNE direction clearly and has close relation with regional tectonic. About 88% of focal depths are within 3-18 km, which suggests that the seismogenic layer lies in the upper crust in North China. We infer that the lowest boundary of seismicity is about 23 km in North China since 97.6% of the focal depths range from 0 km to 23 km. Epicenter locations distribute as a narrow zone in NE direction along Xinhe fault in Xinhe area. Epicenter locations present a "listric" pattern along NW-SE profile, which is steep in the upper and slower in the lower. The epicenter relocations in Tangshan area distribute in three clusters in Tangshan, Luanxian, and Qian'an areas. Furthermore, there present two small obvious faults in the northern part of Tangshan fault. The small fault in the east is slightly deeper.

Key words: North China region, double-difference earthquake relocation method, waveform cross-correlation technology, Xinhe fault, Tangshan fault

CLC Number:

R315.63

CHEN Xiaoqing, YU Xiangwei. Relocation of earthquakes in North China using absolute and relative earthquake relocation methods[J]. Journal of University of Chinese Academy of Sciences, 2015, 32(2): 243-251.

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