柯坪塔格断裂带重复地震识别及其时空特征分析

Identification and spatio-temporal characteristics of repeating earthquakes in Kepingtage fault zone

根据互相关系数不小于0.8的波形互相关意义上重复地震的定义,利用国家数字地震台网中的乌什和巴楚台记录的区域地震波形数据,识别并研究了新疆柯坪塔格断裂带及其周缘的板内重复地震.对所有相互距离不超过30km的地震事件的垂直分量采用0.5—5.0Hz带通滤波后进行波形互相关计算.其中乌什台共识别出460例重复地震,组成重复地震对和多重地震对共171组,占总事件数的15.5%;巴楚台共识别出822例重复地震,组成重复地震对和多重地震对共298组,占总事件数的21.2%.对重复地震的分析表明,台站分布的不同和波形事件记录质量的差异,是造成两个台站识别出的"重复地震"数目和比例不同的原因.对重复地震复发的时间间隔统计表明,重复间隔从数分钟到数百天不等,最长重复间隔达10年.

According to the definition of repeating earthquakes that the wave- form cross-correlation coefficient is not less than 0.8, intraplate repeating earthquakes in and around Kepingtage fault zone, XinJiang, were identified and studied using waveforrn data recorded at WUS and BCH national digital seismic stations. Waveform cross correlation analysis was carried out after 0. 5 5.0 Hzbandpass-filtering on vertical components records from the events being less than 30 km away from each other. Altogether 460 repeating earthquakes were identified from WUS station, which comprised 171 doublets and multiplets, making up 15. 5%of total events： 822 repeating earthquakes were identified from BCH station, which comprised 298 doublets and multiplets, making up 21.2% of total events. Our analysis of the repeating earthquakes show that the difference in the number and proportion of repeating earthquakes between the two stations is attributed to the difference in the distribution of stations and waveform record quality. Statistics show that the time interval between repeat- ing earthquakes ranges from a few minutes to hundreds of days, the longest be- ing 10 years.