Source process of the 1999 Xiuyan earthquake of MS5.4 as revealed by relocation of earthquake sequence
Abstract
On 29 November 1999 at local time 12:10:39 (04:10:39 UTC), an MS5.4 earthquake occurred in Xiuyan of northeastern China, about 30km to the south-east of the 1975 MS7.3 Haicheng, earthquake. This earthquake is the largest event to occur in the Haicheng-Xiuyan region since the 1975 Haicheng earthquake. The focal mechanism of the 1999 Xiuyan earthquake is similar to that of the 1975 Haicheng earthquake, and is a mainly left-lateral strike-slip faulting on a nearly vertical fault plane WNW-ESE striking dipping NNE. Also similar to the 1975 Haicheng earthquake, the 1999 Xiuyan earthquake is a typical earthquake sequence comprising foreshock and aftershock sequences. To study the characteristics of the 1999 Xiuyan earthquake sequence, precise as well as accurate earthquake locations of this sequence were obtained first by employing the double-difference earthquake relocation method with P-phase data recorded by the Liaoning Province Seismic Network and then corrected by using calibration events or ground truth (GT) events recorded by the near-source seismic network, Sino-US Cooperative Haicheng-Xiuyan Seismic Network operated by the Institute of Geophysics, China Earthquake Administration and Southern Methodist University of the US. The relocated and corrected hypocenters of the Xiuyan earthquake sequence clearly indicated that unlike the 1975 Haicheng earthquake which occurred on the WNW-ESE striking Haichenghe-Dayanghe fault, the more likely causative fault of the Xiuyan earthquake is the local WNW-ESE striking Kangjialing fault. The similar focal geometries of the 1975 Haicheng and the 1999 Xiuyan earthquakes suggest that the occurrence of the two events represents the activities of both the WNW-ESE striking regional Haichenghe-Dayanghe fault and its adjacent local Kangjialing fault by the ENE-WSW trending, nearly horizontal compression stress in the northeastern-northern China region.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2010
- Bibcode:
- 2010AGUFM.S21B2027Y
- Keywords:
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- 7200 SEISMOLOGY;
- 7215 SEISMOLOGY / Earthquake source observations