Precise and accurate location of the 1999 Haicheng-Xiuyan earthquake sequence

An earthquake of MS5.4 occurred in Haicheng-Xiuyan area, Liaoning, northeastern China at 12:10:39 BJT (04:10:39 UTC) on November 29, 1999. This event is the largest to occur since the 1975 Haicheng MS7.3 earthquake in Haicheng-Xiuyan area. The foreshocks, mainshock and aftershocks of the sequence were well-recorded by Liaoning Digital Seismic Network (LNDSN). Firstly, we used the regional distance travel time data recorded by the LNDSN to relocate the Haicheng-Xiuyan earthquake sequence by using double-difference earthquake location algorithm. Secondly, the earthquakes with well-recorded near-source recordings by Institute of Geophysics, China Earthquake Administration (IGCEA) and Southern Methodist University (SMU) Broadband Seismic Network (BSN) in the Haicheng-Xiuyan area are employed as ground truth (GT) events to calibrate the source parameters of the Haicheng-Xiuyan earthquake sequence. The obtained precise and accurate hypocentral distribution of the sequence clearly indicated that a nearby local Kangjialing fault is the seismogenic fault of the Haicheng-Xiuyan earthquake sequence. The WNW-ESE striking Kangjialing fault is nearly parallel to the Haichenghe-Dayanghe fault. Both the 1975 Haicheng earthquake and the 1999 Haicheng-Xiuyan earthquake are the consequence under near horizontal, ENE-WSW compression, and the occurrence of the Haicheng-Xiuyan earthquake is the activities of a nearby Kangjialing fault under of influence the Haichenghe-Dayanghe fault.