Assessment of the automatic centroid moment tensor inversion system for global strong earthquakes (MW≥6 .5)based on the W-phase method
Zhao Xu
Duputel Zacharie
Huang Zhibin
Chen Hongfeng
Zhao Bo
Abstract：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 ± 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.
Keywords：W phaseautomatic centroid moment tensor inversionassessment
Publication Date：2014-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：10( 800-809 )