结合波形互相关的双差定位方法在三峡水库地震中的应用

摘要

本文采用基于波形互相关算法的双差定位方法对三峡水库地震进行精定位和地震活动性分析.首先使用双谱互相关方法分析了三峡库区加密台网于2009年3月至2010年12月观测到的地震波形数据,并对波形互相关分析的结果进行了评价.基于结合获得的波形互相关数据使用双差定位方法对地震事件进行精定位研究,结果表明使用双谱法验证的波形互相关数据的定位精度要高于其他数据的结果,其东西向震源位置平均误差为3.2m、南北向为3.9m、垂直向为6.2m.重定位震中结果显示巴东神龙溪两岸微震分布明显呈现出3条近东西向的线性条带状,与地表小规模断裂和碳酸盐岩地层走向一致,揭示了库水主要沿着溶洞或者地下暗河渗透进而诱发地震活动,较强地震可能是微小地震贯穿活动面的结果.%In this paper,we applied the double difference location method based on waveform cross-correlation algorithm for earthquake precision positioning of the Three Gorges Reservoir (TGR).First we used bispectrum cross-correlation method to analyze the seismic waveform data of TGR encrypted networks in March 2009 to December 2010,and evaluate the quality of waveform cross-correlation analysis.Combining the waveform cross-correlation of data obtained,we used the double difference method to relocate the position of quakes.The results show that the location by using bispectrum verified waveform cross-correlation data is higher than other type of data,and the mean 2sig-errors in EW,NS and UD are 3.2m,3.9m and 6.2m,respectively.The results also show that the Badong and Shenlong River quake in reservoir distribution is characterized by linear distribution of three nearly east-west,which is in accordance with the small faults and carbonate strata line of new tectonic period,revealing reservoir water main along the underground river or cave penetration induced seismic activity.A strong earthquake may be the result of a small earthquakes that broken through the active plane.