刘瑞丰, 邹立晔, 张立文. 2018: 汶川地震的面波震级测定及其多普勒效应. 地震学报, 40(3): 364-373. DOI: 10.11939/jass.20170212
引用本文: 刘瑞丰, 邹立晔, 张立文. 2018: 汶川地震的面波震级测定及其多普勒效应. 地震学报, 40(3): 364-373. DOI: 10.11939/jass.20170212
Liu Ruifeng, Zou Liye, Zhang Liwen. 2018: Determination of the surface-wave magnitude of the Wenchuan earthquake and its seismic Doppler effect. Acta Seismologica Sinica, 40(3): 364-373. DOI: 10.11939/jass.20170212
Citation: Liu Ruifeng, Zou Liye, Zhang Liwen. 2018: Determination of the surface-wave magnitude of the Wenchuan earthquake and its seismic Doppler effect. Acta Seismologica Sinica, 40(3): 364-373. DOI: 10.11939/jass.20170212

汶川地震的面波震级测定及其多普勒效应

Determination of the surface-wave magnitude of the Wenchuan earthquake and its seismic Doppler effect

  • 摘要: 本文介绍了全球主要地震机构对2008年5月12日汶川地震参数的速报和修订情况,分析了美国地质调查局国家地震信息中心测定的面波震级。通过对比198个全球地震台站测定的面波震级和面波周期,得出如下结论:测定面波震级偏大的台站主要分布在震中的东北方向,测定面波震级偏小的台站主要分布在震中的西南和东南方向,面波周期偏小的台站主要分布在震中东北方向。由于此次地震破裂方向是以北东向单侧破裂为主,且地震多普勒效应导致震中东北方向振动加强,因此该方向上的面波震级偏大,地震烈度衰减慢;而震中西南方向的振动减弱,此方向面波震级偏小,地震烈度衰减快。从而造成地震烈度沿中央断裂带的北东方向衰减慢,而南西方向衰减快的特征分布。

     

    Abstract: The fast report and revision of the parameters of the Wenchuan earthquake on 12 May 2008 by some major international seismological institutions are introduced, and the surface-wave magnitude measured by National Earthquake Information Center of United States Geological Survey is analyzed in this paper. The comparison of the measured surface-wave magnitudes and periods of 198 global seismic stations reveals that, those stations with larger magnitudes are mainly in NE direction of the epicenter while those with smaller magnitudes are in SW and SE direction, and stations with smaller periods are mainly in NE direction. The seismic intensity map of the Wenchuan earthquake shows that the intensity attenuated slowly in the NE direction of the central fracture zone while the intensity attenuated fast in the SW direction. The reason is that Wenchuan earthquake is a unilateral rupture mainly in NE direction, due to the seismic Doppler effect, the stronger shaking leads to the larger surface-wave magnitudes and slower intensity attenuation in the NE direction of the epicenter, vice versa the weaker shaking leads to the smaller surface-wave magnitudes and faster intensity attenuation in the SW direction.

     

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