Is clustered seismicity an indicator of regional stress? Insights from earthquake sequences in Yongning-Luguhu faulted basin, Southwest China

Earthquake Research Advances Pub Date : 2022-07-01 DOI:10.1016/j.eqrea.2022.100138

Xinglin Lei , Guangming Wang

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引用次数: 3

Abstract

Using hypocenter relocation, moment tensor inversion, stress field inversion, and fault slip tendency analysis, this study systematically investigated three M5.5–5.8 earthquake sequences that occurred after 2000 in the Yongning-Luguhu faulted basin in the middle of the Lijiang-Xiaojinhe fault zone within the Sichuan-Yunnan block, Southwest China. Our results show that since the 2008 Wenchuan Earthquake, the tectonic stress pattern in this area may have changed and that b-values estimated for the earthquake sequences show evidence of an increasing trend in stress in the study area. Seismicity in the small-scale faulted basin adjacent to the large-scale fault zone is a possible indicator of regional stress. We also note that the aftershocks of the M5.7 earthquake sequence in 2012 and the M5.5 earthquake sequence in 2022 show relatively clear fluid diffusion-triggering characteristics. Overpressure of deep fluids is still the main factor driving seismic activity in the region, and we propose that the background tectonic stresses have not yet reached critical levels.

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群集地震活动是区域应力的一个指标吗?永宁-泸沽湖断陷盆地地震序列的启示

采用震源定位、矩张量反演、应力场反演和断层滑动趋势分析等方法，系统研究了川滇地块丽江—小金河断裂带中段永宁—泸古湖断陷盆地2000年以后发生的3次5.5 ~ 5.8级地震序列。结果表明，自2008年汶川地震以来，该地区的构造应力格局可能发生了变化，地震序列的b值表明研究区应力有增加的趋势。与大型断裂带相邻的小型断陷盆地的地震活动性可能是区域应力的指示。2012年5.7级地震序列和2022年5.5级地震序列的余震表现出较为明显的流体扩散触发特征。深部流体超压仍是该区地震活动的主要驱动因素，背景构造应力尚未达到临界水平。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Earthquake Research Advances

CiteScore

4.30

自引率

0.00%

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