M_(WP)震级测定方法在全球中强地震自动测定中的应用

Application of the method of M_(WP) determination in the automatic determination of global moderate and strong earthquakes

本文使用M_(WP)震级测定方法,对地震参数自动测定系统进行了改进,实现了对全球M_W≥6.0地震震级更快更精确的自动测定.与传统的M_L、M_S等震级测定方法相比,M_(WP)震级测定方法有2个显著优点:1由于只使用P波列,因此该方法可使用S波或面波限幅记录,可用波形资料较多;2选取的时间窗位于S波之前,震级测定速度更快.对地震参数自动测定系统在2014年9月22日至2015年12月22日测定的254个全球M_W≥6.0地震参数进行分析,结果表明,M_(WP)与全球矩心矩张量(GCMT)产出的M_W的一致性较好,无明显系统偏差,86.2%的M_(WP)与M_W的偏差绝对值小于等于0.3,可在震后平均531 s获得全球地震时空强参数.中国地震台网对全球中强地震时空强参数的自动测定与准实时地震信息服务,对于提高中国地震台网对全球地震的应急处置能力,提升中国在国际防震减灾领域的影响有现实意义.

We utilize the method of Mwp determination to improve the Automatic Earthquake Determination System that realizes the faster and more accurate determination of the moderate and strong earthquakes automatically with Mw≥ 6. 0 all over the world. Compared with the determination methods of the traditional magnitudes MLand Ms, the method of Mwp determination has two significant advantages： more seismograms whose S wave and surface wave are clipped can be used because only P waves are used in the method. The selected time window is before the S wave, therefore the determination of magnitude is faster. The analysis of the results of the parameters of 254 global earthquakes with Mw ≥6.0 occurred between September 22, 2014 and December 22, 2015 produced by the Automatic Earthquake Determination System shows that the result of Mwp have a good consistency with the moment magnitude Mw derived from Global Centroid Moment Tensor （GCMT） solutions and have no obvious systematic deviation. The absolute deviation value of Mwp is less or equal to 0.3 for 86.2 percent events and the parameters can be determined within 531 s after an earthquake averagely. The automatic determination of the parameters of global moderate and strong earthquakes and the service of quasi real time earthquake information provided by CSN have practical significance for the improvement of the CSN＇ s response to global earthquakes and the enhancement of China＇ s influence in the field of international earthquake prevention and disaster mitigation.