GPS观测得到的汶川地震远场地面运动

通过对汶川地震时天津12个GPS连续站上的每秒采样的GPS观测资料和蓟县地震台上宽频带地震计实时记录资料，采用单历元精密定位方法研究了在这些GPS连续站在汶川地震观测到的远场地面运动。结果表明，利用每秒采样的连续GPS观测资料可以有效地记录到汶川8．0级地震在1500km以外的远场地面水平运动。而且在震中距大体相同的的情况下，地面运动的强烈程度主要受同样观测墩高度及观测墩基础地质条件的影响。但目前的精度水平下尚不能得到远场地面垂直运动的可靠信息。

Far-Field Ground Motion of the Wenchuan Earthquake Observed by GPS

The sampling data collected per second from the 12 GPS continuous operation reference stations in Tianjin and the data of wideband seismograph at Jixian seismic station during the period of Wenchuan earthquake are analyzed.By using single epoch precision positioning technique,the coseimic ground motions at the 12 GPS stations during the Wenchuan earthquake are studied.The results indicate that,even in excess of 1500 km the far-field level ground motions caused by the Wenchuan earthquake can be effectively recorded by continuous observation GPS data with the sampling per second.And almost in the same distance,the ground motion is mainly influenced by the height of the observation and geological conditions of the pier.Unfortunately,the present precision is limited to obtain reliable information from the the far-field vertical ground.