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Title:: Far-Field Coseismic Displacements Associated with the 2011 Tohoku-oki M_W9.0 Earthquake,Japan,Observed by Campaign GPS Observation Data

Author(s):: ZHAO Jingyang; WU Yanqiang; LIANG Hongbao; DU Kaifu; SHI Shuangshuang; (The First Monitoring and Application Center,China Earthquake Administration,Tianjin 300180,China)

Keywords:: campaign GPS observation; constrained calculation; coseismic displacement; the Tohoku-oki M_W9.0 earthquake

摘要:: 采用1999—2017年我国东北和华北地区的流动GPS观测资料,对比坐标时间序列直接解算、连续GPS同震位移插值结果约束解算、位错模型模拟同震位移约束解算和由上述2种外部数据同时约束解算等4种解算策略,获得了2011年日本M_W9.0地震远场同震位移,并由该远场同震位移约束反演了此次地震的静态位错。结果表明:在利用流动GPS解算量级较小的同震位移时,由外部可靠数据作为约束可获得较为理想的结果; 流动GPS测定的2011年日本M_W9.0地震在我国东北和华北地区造成的远场同震位移最大可达33 mm,以东向位移为主; 由远场同震水平位移和近场同震垂直位移约束得到的静态位错对应的矩震级M_W为8.77,最大同震位错量为21.09 m。

Abstract:: The campaign GPS observations in the northeastern China from 1999 to 2017 are used to derive the far-field coseismic displacements of the 2011 Tohoku-oki M_W9.0 earthquake,Japan.The strategies include direct calculation with the coordinate time series,constrained calculation with the interpolated coseismic displacements from continuous GPS observations,constrained calculation with the simulated coseismic displacements from dislocation model and constrained calculation with both the above two external data are compared.Then the best far-field coseismic horizontal displacements as well as the near field coseismic vertical displacements are used to invert the static dislocation model of the earthquake.The results show that when the campaign GPS data are used to inverse the coseismic displacements of small magnitude,using external reliable data as constraint is conducive to getting more satisfactory results.And the maximum far-field coseismic displacements in northeastern China can reach 33 mm and the dominated displacements is eastward.The resultant moment magnitude corresponding to the coseismic dislocation inversion is M_W8.77 and the largest dislocation of this earthquake is 21.09 m.