龙门山断裂带周缘重复地震识别及其在台网定位评价中的应用

地震 ›› 2019, Vol. 39 ›› Issue (3): 166-177.

龙门山断裂带周缘重复地震识别及其在台网定位评价中的应用

孟真¹, 宋晓东^1,2

1.武汉大学测绘学院, 湖北武汉 430079;
2.伊利诺伊大学香槟分校地质系, 美国香槟 61820

收稿日期:2019-03-07 出版日期:2019-07-31 发布日期:2019-08-09
通讯作者: 宋晓东, 教授。 E-mail: xiao.d.song@gmail.com
作者简介:孟真(1993-), 女, 河南洛阳人, 在读硕士研究生, 主要从事重复地震研究
基金资助:
国家自然科学基金(41774056)和地震科研公益性行业专项(201508020)资助

Recognition of Repeating Earthquake around Longmenshan Fault Zone and Its Application to Station Network Location Evaluation

MENG Zhen¹, SONG Xiao-dong^1,2

1.School of Geodesy and Geomatics, Wuhan University, Wuhan 430079, China;
2.Department of Geology, University of Illinois at Urbana-Champaign 61820, USA

Received:2019-03-07 Online:2019-07-31 Published:2019-08-09

摘要/Abstract

摘要： 利用国家测震台网数据备份中心时间跨度超过7年的连续波形资料, 设定至少三个台站记录的垂直分量波形互相关系数大于0.8的地震对为一组重复地震, 通过波形互相关分析, 识别出龙门山断裂带周缘波形相关意义上的“重复地震”2790次, 构成2907组重复地震。沿用Schaff和Richards的研究结果, 假定“重复地震”间距很小(小于1 km), 地震目录记录的重复地震对位置之差主要为地震台网的定位误差所致, 基于此误差给出了龙门山断裂带周缘地震台网的定位精度估计: 台网的水平定位精度较高, 水平定位误差约为2.8 km(2倍标准差), 且西南段台网的水平定位精度优于中北段; 垂直定位精度较差, 垂直定位误差约为10 km(2倍标准差), 现有地震定位方法对震源深度的测定有待改善。

关键词: 重复地震, 波形互相关, 台网定位精度, 龙门山断裂带

Abstract: Repeating earthquakes have been used in assessing the location accuracy of the seismograph network for more than a decade. In this study, we used the continuous waveform data recorded by the State Earthquake Information Service Digital Media Center (SEIS DMC) between August 2007 and December 2014 to search for repeating earthquakes along the Longmenshan fault zone (LMSFZ). We obtained 2790 repeating earthquakes by using cross-correlation analysis of waveform data, based on the principle that repeating events should be recorded by at least 3 stations and have a cross-correlation coefficient C＞0.8. With the assumption that the repeating events were separated by no more than 1 km, the location difference of repeating earthquakes recorded by seismic catalogue is mainly caused by the positioning error of seismic network. Based on this error, weestimate the positioning accuaracy of seismic network around Longmenshan fault zone. It is observed that the “horizontal location error” of seismograph network near LMSFZ is estimated to be below 5 km, with an average of 2.8 km. And the average location accuracy of the southwestern segment of the LMSFZ is better than that of the central-northern segment. The results also show that the “vertical location error” is estimated to be about 10 km.

Key words: Repeating earthquakes, Waveform cross-correlation, Location accuracy, Continuous waveform

中图分类号:

P315.7

孟真, 宋晓东. 龙门山断裂带周缘重复地震识别及其在台网定位评价中的应用[J]. 地震, 2019, 39(3): 166-177.

MENG Zhen, SONG Xiao-dong. Recognition of Repeating Earthquake around Longmenshan Fault Zone and Its Application to Station Network Location Evaluation[J]. EARTHQUAKE, 2019, 39(3): 166-177.

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