利用背景噪声研究滇西北波速异常与M≥5.0地震关系  

Study on the Relationship between Wave Velocity Anomalies and M ≥5.0 Earthquakes in Northwestern Yunnan Using Ambient Noise

作　　者：杨建文 叶泵 高琼 陈佳 王军 YANG Jianwen;YE Beng;GAO Qiong;CHEN Jia;WANG Jun(Dali Center of China Earthquake Science Experimental Site,Binhai Road,Dali 671000,China;Field Scientific Observation and Research Station on Crustal Tectonic Activities in Northwest Yunnan,Binhai Road,Dali 671000,China)

机构地区：[1]中国地震科学实验场大理中心,云南省大理市671000 [2]云南大理滇西北地壳构造活动野外科学观测研究站,云南省大理市671000

出　　处：《大地测量与地球动力学》2022年第2期165-171,共7页Journal of Geodesy and Geodynamics

基　　金：中国地震局震情跟踪定向工作任务(2021010105);中国地震局“三结合”课题(3JH-2021045);中国地震局地球物理研究所基本科研业务费专项(DQJB21Z02);云南省地震局科技人员传帮带培养项目(CQ3-2021004);云南省陈颙院士工作站(2014IC007)。

摘　　要：提出基于背景噪声波速测量的综合预测指标法,将测震资料更好地应用于震情跟踪和地震短临预报。利用滇西北5个台站2012-01~2020-11宽频带连续波形资料,基于背景噪声互相关及傅立叶变换等方法,提取10个台站对当天经验格林函数与参考经验格林函数的直达瑞利波走时偏移时间序列,设定±1.5倍标准差作为异常阈值,并以其间发生的6次M≥5.0地震为样本,采用R值评分法对每个台站对的映震能力进行效能检验,最后基于自适应加权综合预测方法提取适合于滇西北地区的地震短临异常识别指标(综合指标)。结果表明,利用该综合指标对滇西北2012年以来发生的6次M≥5.0地震进行90 d短临预报,异常指标共出现8次,其中准确预报地震5次,漏报1次,虚报4次,预报效能评分R为0.692,R_(0)为0.475。该综合指标的地震对应率为62.50%,概括率为83.33%。We propose a comprehensive prediction index method based on the measurement of ambient noise wave velocity to better apply the seismic data to earthquake situation tracking and short-term and imminent earthquake prediction.Using broadband continuous waveform data from January 2012 to November 2020 recorded at 5 stations in northwestern Yunnan,based on ambient noise cross-correlation and Fourier transform methods,we extract the direct Rayleigh wave travel time offset time series of day empirical Green’s function and reference empirical Green’s function of 10 station pairs.We set±1.5 times the standard deviation as the anomaly threshold,take 6 earthquakes with M≥5.0 as samples,and use the R value scoring method to test earthquake capability of each station pair.Finally,based on the adaptive weighted comprehensive prediction method,we extract the short-term and imminent earthquake anomaly identification index(comprehensive index)suitable for northwestern Yunnan.The results show that when the comprehensive index is used for 90-day short-term and imminent prediction of 6 earthquakes with M≥5.0 occurring in northwestern Yunnan since 2012,a total of 8 abnormal indicators have occurred,of which 5 earthquakes are accurately predicted,1 missed report,and 4 false reports.The predictive performance score R is 0.692,R_(0) is 0.475.The earthquake response rate of this comprehensive index is 62.50%,and the generalization rate is 83.33%.

关 键 词：背景噪声 波形互相关 傅立叶变换 波速变化 短临预报 综合指标 

分 类 号：P315[天文地球—地震学]