地震地质 ›› 2010, Vol. 32 ›› Issue (3): 508-519.DOI: 10.3969/j.issn.0253-4967.2010.03.018

• 综合研究 • 上一篇    下一篇

利用重复地震估算北京平原地区隐伏断裂深部的活动速率

李乐, 陈棋福   

  1. 中国地震局地震预测研究所, 北京, 100036
  • 收稿日期:2010-02-23 修回日期:2010-07-20 出版日期:2010-09-30 发布日期:2011-01-14
  • 作者简介:李乐,女,1976年生,2008年在中国地震局地球物理研究所获博士学位,助理研究员,现主要从事重复地震与活动构造以及小震精确定位方面的研究,电话:010-88015651,E-mail:lile@seis.ac.cn.
  • 基金资助:
    中国地震局地震预测研究所基本科研业务专项(02092405)资助

SLIP RATES AT DEPTH ALONG THE BURIED FAULTS IN BEIJING PLAIN AREA ETSTIMATED FROM REPEATING MICROEARTHQUAKES

LI Le, CHEN Qi-fu   

  1. Institute of Earthquake Science, China Earthquake Administration, Beijing 100036, China
  • Received:2010-02-23 Revised:2010-07-20 Online:2010-09-30 Published:2011-01-14

摘要: 利用首都圈数字化地震台网2001—2006年的波形资料分析北京平原地区隐伏断裂的深部滑动速率。通过波形互相关分析,识别出35组相似地震对和20组多重相似对,大部分相似地震活动表现为非周期性,重复间隔从数分钟到数百天不等。针对研究区内台站分布稀疏和低信噪比波形记录的现状,在波形相似的基础上,提出了采用在子采样条件下的S-P相对到时差(dSmP)和相对到时拾取误差来对相似地震震源位置的一致性进行强约束,进一步探索和完善波形意义上重复地震的识别方法。基于4组"重复地震"估算北京平原区黄庄-高丽营断裂和南口-孙河断裂在不同孕震深度处的滑动速率为1.0~1.2mm/a,怀安镇盆地南缘断裂地表以下9.4km处的滑动速率估计值为1.5mm/a,这一结果和地质资料结果相符。

关键词: 隐伏断裂, 重复地震, 滑动速率, 北京平原地区

Abstract: Slip rates along the buried faults in Beijing plain area were investigated with the seismic waveform data between 2001 and 2006 recorded by the Beijing Digital Seismic Network.Using cross-correlation analysis of available waveforms,we identified a total of 35 doublets and 20 multiplets that show high waveform similarity.Most of these sequences are aperiodic with recurrence intervals varying from a few minutes to hundreds of days.Given the limited quantity and quality of seismic data in the study area,we have chosen a more robust approach to constrain repeated event locations.The approach incorporates both seismogram similarity by requiring cross correlation threshold and location similarity by requiring differential S-P(dSmP) time between events pairs to be small and minor internal inconsistence in travel time picking at sub-sample precision.The composite selection approach improves the identification of repeating earthquake based on similarity in waveforms.Based on four repeating sequences,we obtained the slip rate about 1.0 ~ 1.2mm/a at seismogenic depths of Hangzhuang-Gaoliying Fault and Nankou-Sunhe Fault,and the slip rate of 1.5mm/a at 9.4km of the south boundary fault of Huai' an Basin,which is consistent with geological and geodetic measurements.

Key words: buried faults, repeating microearthquake, slip rate of fault, Beijing plain area

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