基于W震相技术的全球强震(M_W≥6.5)矩心矩张量自动反演系统评估  

Assessment of the automatic centroid moment tensor inversion system for global strong earthquakes(M_W≥6.5)based on the W-phase method

作　　者：赵旭[1,2] Duputel Zacharie 黄志斌[1] 陈宏峰[1] 赵博[1] 

机构地区：[1]中国地震台网中心,中国北京100045 [2]中国科学院地质与地球物理研究所,中国北京100029 [3]加州理工学院地震学实验室,美国加州91125

出　　处：《地震学报》2014年第5期800-809,980,共10页Acta Seismologica Sinica

基　　金：地震科技星火计划项目(XH12060Y);地震行业科研专项(201208003)共同资助

摘　　要：使用最近构建的虚拟全球地震台网记录的波形数据,采用OpenMP的并行编程技术优化原有算法,研制了基于W震相技术的全球强震(MW≥6.5)矩心矩张量自动反演系统.为了评估该系统的准确度和时效性,将离线自动测定的2008年1月—2013年7月全球140次地震(MW6.5—9.0)的矩心矩张量与全球矩心矩张量工作组(GCMT)的结果进行了比较.结果表明:该系统可准确测定全球MW≥6.5地震的矩张量,绝大多数地震矩震级与GCMT给出的矩震级呈现出良好的线性趋势,两者之差ΔMW的标准方差约0.13,ΔMW位于区间(-0.2,0.2)的地震占总数的96%;地震矩6个分量分别与GCMT相应的结果沿对角线近线性分布,多数地震矩心水平位置与GCMT给出的矩心水平位置比较接近,两者间大圆弧距离位于区间(0,50km)的地震次数占总数的84%;在台站覆盖较均匀的条件下,该系统能够实现震后25—40分钟自动准确测定全球MW≥6.5地震的矩心矩张量.We develop an automatic centroid moment tensor （CMT ）inversion system for large earthquakes （MW≥6 .5 ）at global scale based on the W-phase method.We use seismic waveforms observed by global virtual seismic networks including Chinese stations,which have been recently set up.To speed up the calculation of moment tensor solutions,the W-phase method is parallelized using openMP.In order to assess the accuracy and timeliness of this implemen-tation,automatic moment tensor solutions for 140 global events （MW6.5-9.0） are determined offline.Compared with the global CMT （GCMT）solutions,the result indicates that this system mentioned is able to precisely retrieve CMT so-lutions of global events with MW≥6 .5 .There is remarkably good linear rela-tionship between the moment magnitude of W-phase CMT and GCMT.The standard deviation of the magnitude differenceΔMW is about 0 .1 3 ,and 9 6 per-cent of the inversions yield a MW within MW-GCMT from the GCMT ＆#177; 0 .2 .In comparison with the GCMT solutions,six elements of moment tensors derived show nearly linear distribution along the diagonal,respectively.84 percent of inversions yield a great-circle distance smaller than 50 km between the CMT and GCMT centroids.As shown above,majority of the centroids are very similar with the GCMT centroids.When the data coverage is sufficient,this system can thus automatically determine the CMT of global earthquakes with MW≥6 .5 in between 25 min and 40 min after the origin time.

关 键 词：W震相 矩心矩张量自动反演 评估 

分 类 号：P315.63[天文地球—地震学]