地震学报（英文版）1999，Vol.12Issue(1)：63-72,10.
A study on seismic source process in short- term and imminent stage before destructive mining shock
A study on seismic source process in short- term and imminent stage before destructive mining shock
摘要
Abstract
Three destructive mining shocks successively occurred nearby the seismic Station No.6 located in a shaft of the Fangshan Coal Mine of Beijing Mining Service in 4 minutes at 19 o′clock of May 15, 1993. The largest shock is of M=2.3 (M0=1.5×1011 N·m). Analysis of synthetic seismogram provides that the three shocks exhibited predominantly a dip-slip movement mode, which is consistent with the collapse of coal mass from the coal bed at high dip-angle, as observed by those who were present at the site. The near-field records of the main shock and a series of events prior to it made at the Station No.6 are different from normal records, it had not only high-frequency vibration, but also low-frequency vibration. By using elastic wave theory and nucleation theory of seismic fracture during recent years, analysis of the data indicates that the low-frequency vibration maybe long-period wave as the subcritical extension is pushing forward. It is an unrecovered deformation. The high-frequency vibration is just the mining shock event, exhibiting a wave field of brittle fracture radiation. From the dominant frequency of low-frequency vibration in the records of M=2.3 event and the records of foreshocks at 5.4 s before it, it is inferred that the volume of dilatation zone at the termination of shock-generating fracture has rapidly enlarged during the occurrence of the main shock. In 20 or more days before the main shock, the source process was of the following characteristics: the subcritical extension occurred for many times; during this period the volume of dilatation zone at the termination of shock-generating fracture little changed. The subcritical extension not only exits long-period waves, but also induced small events at the same time. The dominant orientation of subcritical extension is basically consistent with the direction of slip movement during main shock.关键词
mining shock high-frequency vibration low-frequency vibration subcritical extensionKey words
mining shock high-frequency vibration low-frequency vibration subcritical extension分类
天文与地球科学引用本文复制引用
..A study on seismic source process in short- term and imminent stage before destructive mining shock[J].地震学报（英文版）,1999,12(1):63-72,10.基金项目
Contribution No. 99FC2006, Institute of Geophysics, China Seismological Bureau. （）
