金沙江鲁地拉水库蓄水前后地震活动性分析  

Characteristic Analysis of Seismicity in Ludila Reservoir on Jinsha River Before and After the Water Storage

作　　者：段炜[1] 朱智娇 刘杰 庄儒新[1] 李圣 DUAN Wei;ZHU Zhijiao;LIU Jie;ZHUANG Ruxin;LI Sheng(Yunnan Earthquake Agency,Yunnan Kunming 650041,China;Yunnan Zhenke Seismic Technology Engineering Company,Yunnan Kunming 650041,China;Kunming Engineering Corporation Limited,Yunnan Kunming 650000,China)

机构地区：[1]云南省地震局,云南昆明650041 [2]云南震科抗震技术工程公司,云南昆明650041 [3]中国电建集团昆明勘测设计研究院有限公司,云南昆明650000

出　　处：《防灾减灾学报》2023年第4期48-55,共8页Journal of Disaster Prevention And Reduction

基　　金：云南省地震局青年基金自主立项课题(2022ZLK02)。

摘　　要：利用2008年1月至2017年12月全国地震编目系统及鲁地拉水库地震专用台网所记录的2726次地震,对水库蓄水前后地震活动从最小完整性震级、震中分布、M-t关系、频度、震源深度、b值等方面,结合水库水位变化及地质构造活动背景进行分析,并对发生M4.2地震前后一个月时间的地震用双差地震定位方法进行重新定位。综合分析结果表明:蓄水后地震活动显著增强,与水位变化有较强的相关性,特别是记录了大量M_(L)≤0.9地震,此为水库诱发地震可能性大,空间上呈丛集分布,并沿程海-宾川断裂展布;水库蓄水对研究区10 km深度范围内的地震有显著影响;蓄水后研究区M_(L)≥1.5地震反映为构造地震的特征;对M4.2震群分析可知,离库岸近的位置浅源地震较多。从历史上看,研究区约每12年左右会发生一次4.5级左右的有感地震,此次有感地震发生时间虽与水库蓄水相关,但也可能是水库蓄水引起该库段的溶岩作用和断层活动共同触发了构造地震。Based on the 2,726 earthquakes recorded by the national earthquake cataloging system and Lu-dila reservoir seismic network from January 2008 to December 2017,the seismic activity before and after the water storage was analyzed from the minimum magnitude of completeness,epicenter distribution,M-t relation,frequency,focal depths and b value,combined with the variation of water level of the reservoir and the background of geological tectonic activity,and the double-difference seismic location method was used to reposition the earthquakes in a month before and after the M4.2 earthquake.The comprehensive anal-ysis results showed that:after water storage,the seismic activity was significantly enhanced,which was strongly correlated with the change of water level.In particular,a large number of M_(L)<0.9 earthquakes were recorded,which showed a high probability of reservoir induced earthquake,distributed in clusters in space,and distributed along the chenghai-binchuan fault.The reservoir impoundment has a significant ef-fect on the earthquake within 10 km depth of the study area.After water storage,the M_(L)≥1.5 earthquakes in the study area was reflected as the characteristics of tectonic earthquakes.The M4.2 earthquake clusters analysis shows the location of the near reservoir bank shallow earthquakes more.Historically,the study area has happened around a 4.5-magnitude earthquake every 12 years or so.Although the occurrence time of the felt earthquake is related to reservoir water storage,it may be that the reservoir water storage caused the dis-solution of rock and fault activities in the reservoir section jointly triggered the tectonic earthquake.

关 键 词：鲁地拉水库 地震活动特征 双差地震定位 震源深度 

分 类 号：P642[天文地球—工程地质学] TU452[天文地球—地质矿产勘探]