用超长基线解算分析汶川地震动态形变特征
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摘要
以远距离的IGS武汉GPS站为参考站,用超长基线双差瞬时精密定位技术,获取汶川Ms8.0地震震时震区连续GPS站1 Hz动态形变序列。同时以较近距离的雅安站为参考站解算动态形变序列,结果显示,两者的形变结果具有很好的一致性。距离断层较近的郫县、成都、绵阳、中江等站形变较大(形变最大的郫县站最大振幅达1.034 m);位于震中南侧的邛崃、雅安等站形变较小。利用动态时序的地震波到时和震中距离估计地震波地壳平均速度为3.1 km/s。
We used Wuhan,one of IGS stations,as a reference to form ultra long baseline and solve instantaneous 1-Hz-GPS positions and measure the co-seismic kinematic deformations caused by Wenchuan earthquake.Compared with the results from using Yaan as the reference which is nearby 1-Hz-GPS stations,the deformation solutions show good consistence with different reference stations.The maximum deformation amplitude is found for station Pixian,which had the largest deformation about 1.034 meter.The deformations of stations,such as Pixian,Chengdu,Mianyang,Zhongjiang are relatively larger and also show the propagation direction of seismic waves.The smaller deformations occurred in Qionglai,Yaan,in the south of the epicenter,which indicate that the fault ruptured from the epicenter to the northeast.On the basis of the arrival time of seismic wave recorded in kinematic time series and the distance between 1-Hz-GPS stations and the epicenter,the estimated average velocity of seismic wave in the crust is 3.1 km/s.
We used Wuhan,one of IGS stations,as a reference to form ultra long baseline and solve instantaneous 1-Hz-GPS positions and measure the co-seismic kinematic deformations caused by Wenchuan earthquake.Compared with the results from using Yaan as the reference which is nearby 1-Hz-GPS stations,the deformation solutions show good consistence with different reference stations.The maximum deformation amplitude is found for station Pixian,which had the largest deformation about 1.034 meter.The deformations of stations,such as Pixian,Chengdu,Mianyang,Zhongjiang are relatively larger and also show the propagation direction of seismic waves.The smaller deformations occurred in Qionglai,Yaan,in the south of the epicenter,which indicate that the fault ruptured from the epicenter to the northeast.On the basis of the arrival time of seismic wave recorded in kinematic time series and the distance between 1-Hz-GPS stations and the epicenter,the estimated average velocity of seismic wave in the crust is 3.1 km/s.
引文
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4 Yusuke Yokota,et al.Ability of 1-HZ GPS to infer thesource process of a medium-sized earthquake:the 2008Iwate-Miyagi Nairiku,Japan,earthquake[J].GeophysicalResearch Letters,2009,36(L12301).
5熊永良,等.长距离动态GPS数据处理方法与汶川地震引起的动态地壳形变特征分析[J].武汉大学学报(信息科学版),2009,34(3):265-269.(Xiong Yongliang,etal.Long distance kinematic GPS data processing and kine-matic crustal deformation features analysis of Wenchuanearthquake[J].Geomatics and Information Science of Wu-han University,2009,34(3):265-269)
6徐韶光,等.汶川地震同震形变的静态和动态分析[J].大地测量与地球动力学,2010,(3):27-30,54.(Xu Sha-oguang,et al.Static and kinemaic analysis of coseismic de-formation of Wenchuan 8.0 earthquake[J].Journal of Geod-esy and Geodynamics,2010,(3):27-30,54)
7吴建平,等.川滇地区速度结构的区域地震波形反演研究[J].地球物理学报,2006,49(5):1 369-1 376.(WuJianping,et al.Regional waveform inversion for crustal andupper mantle velocity structure below Chuandian region[J].Chinese Journal of Geophysics,2006,49(5):1 369-1 376)
8杨海燕,等.川西地区壳幔结构与汶川Ms8.0地震的孕震背景[J].地球物理学报,2009,52(2):356-364.(Yang Haiyan,et al.Crust-mantle structure and seismogen-ic background of Wenchuan Ms8.0 earthquke in Western Si-chuan area[J].Chinese Journal of Geophysics,2009,52(2):356-364)
2 Bock Y,et al.Instantaneous geodetic positioning at mediumdistances with the Global Positioning System[J].J GeophysRes.,2000,105(B12),28 223-28 253.
3 Chen Ji,et al.Slip history of the 2003 Simeon earthquakeconstrained by combining 1-Hz GPS,strong motion andteleseismic data[J].Geophysical Research Letters,2004,31,L17608,doi:10.1029/2004GL020448.
4 Yusuke Yokota,et al.Ability of 1-HZ GPS to infer thesource process of a medium-sized earthquake:the 2008Iwate-Miyagi Nairiku,Japan,earthquake[J].GeophysicalResearch Letters,2009,36(L12301).
5熊永良,等.长距离动态GPS数据处理方法与汶川地震引起的动态地壳形变特征分析[J].武汉大学学报(信息科学版),2009,34(3):265-269.(Xiong Yongliang,etal.Long distance kinematic GPS data processing and kine-matic crustal deformation features analysis of Wenchuanearthquake[J].Geomatics and Information Science of Wu-han University,2009,34(3):265-269)
6徐韶光,等.汶川地震同震形变的静态和动态分析[J].大地测量与地球动力学,2010,(3):27-30,54.(Xu Sha-oguang,et al.Static and kinemaic analysis of coseismic de-formation of Wenchuan 8.0 earthquake[J].Journal of Geod-esy and Geodynamics,2010,(3):27-30,54)
7吴建平,等.川滇地区速度结构的区域地震波形反演研究[J].地球物理学报,2006,49(5):1 369-1 376.(WuJianping,et al.Regional waveform inversion for crustal andupper mantle velocity structure below Chuandian region[J].Chinese Journal of Geophysics,2006,49(5):1 369-1 376)
8杨海燕,等.川西地区壳幔结构与汶川Ms8.0地震的孕震背景[J].地球物理学报,2009,52(2):356-364.(Yang Haiyan,et al.Crust-mantle structure and seismogen-ic background of Wenchuan Ms8.0 earthquke in Western Si-chuan area[J].Chinese Journal of Geophysics,2009,52(2):356-364)
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