云南地区强震前小震调制比特征分析  

Analysis of characteristics of small earthquake modulation ratio before strong earthquakes in Yunnan region

作　　者：孙楠 付虹[2] 彭关灵[2] 刘自凤 SUN Nan;FU Hong;PEGN Guanling;LIU Zifeng(School of Earth and Space Sciences,University of Science and Technology of China,Hefei 230026,China;Yunnan Earthquake Agency,Kunming 650224,China)

机构地区：[1]中国科学与技术大学地球和空间科学学院,安徽230026 [2]云南省地震局,昆明650224

出　　处：《地震地磁观测与研究》2021年第5期82-89,共8页Seismological and Geomagnetic Observation and Research

基　　金：中国地震局震情跟踪定向工作任务(项目编号:2020010128);云南省地震局科技专项(项目编号:2020ZX02)。

摘　　要：利用调制比时空扫描方法,对1973—2014年云南地区M_(S)≥6.0地震进行回溯性研究,分析强震前区域小震调制比时空演化过程。结果显示,从小震调制比异常开始至发震的持续时间为1.5 a之内,调制比异常的最高值需大于0.57,强震多发生在调制比为最高值时或其后14个月内异常区边界或内部调制比显著高值附近,震级随异常持续时间的延长大致呈增加的趋势;小滇西—滇西北地区的强震多发生在调制期内;从分区来看,滇西南强震多发生在调制比为最高值(R_(m)≥0.57)后6个月内的异常边界处,尤其是3个月内,滇西北强震多发生在最高值(R_(m)≥0.67)后7—12月内异常区内显著高值附近,滇东北强震多发生在最高值(R_(m)≥0.67)时的异常区内。Using the spatiotemporal scanning method of modulation ratio(R_(m)),a retrospectively study of M_(S)≥6.0 earthquakes in the Yunnan region from 1973 to 2014 was carried out to analyze R_(m) spatiotemporal evolution of regional small earthquakes before strong earthquakes.The results show that the duration from the start of anomalies to earthquake occurrence is less than 1.5 years,the max R_(m) value should be greater than 0.57,strong earthquakes mostly occur at the time of the max R_(m) or within 14 months afterward and the epicenters are always located at the boundary of the anomaly area or near the significant-high R_(m) place in the anomaly area,there is a general increasing trend for magnitude with anomaly duration.Strong earthquakes usually occur in western Yunnan.In terms of regions,most strong earthquakes in southwest Yunnan occur within 6 months,especially 3 months,after the max R_(m) value(R_(m)≥0.57)at the boundary of the anomaly area,and strong earthquakes in northwest Yunnan often occur within 7-12 months after the max R_(m) value(R_(m)≥0.67)near significant-high R_(m) place in the anomaly area,strong earthquakes in northeast Yunnan mostly occur at the time of the max R_(m) value(R_(m)≥0.67)in the anomaly area.

关 键 词：强震 小震调制比 异常判别 

分 类 号：P315[天文地球—地震学]