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为了更好地了解三峡库区的稳定性,利用三峡库区的流动宽频地震仪台阵于2011年4~5月期间观测的背景噪声数据,采用互相关方法提取了瑞利面波的格林函数,用多重滤波方法获得了瑞利面波的群速度频散曲线.利用走时层析成像方法获得了0.5~10.0s周期的纯路径频散曲线,进而反演获得了沿巴东-茅坪-土门方向的横波速度结构剖面,揭示了三峡地区上地壳的速度变化情况.研究表明:(1)研究区地下速度结构与地质构造关系密切,速度剖面上很好地反映了一个以黄陵背斜核部为中心的背斜构造;(2)九畹溪及其周边区域下方较快的速度变化可能与对应的区域断裂构造、地震活动性密切相关;(3)三斗坪地区上地壳表现为高速,表明三峡坝区处于构造稳定区域.
In order to better understand the stability of the Three Gorges reservoir area, the Green’s function of Rayleigh surface wave was extracted by the cross-correlation method using the background noise data of the mobile broadband seismograph array in the Three Gorges Reservoir from April to May 2011. , The group velocity dispersion curve of Rayleigh wave was obtained by multiple filter method.The pure path dispersion curve of 0.5 ~ 10.0s period was obtained by the time-lapse tomography method, The results show that: (1) The underground velocity structure in the study area is closely related to the geological structure, and the velocity profile reflects a well-behaved structure of Huangling dorsal (2) the rapid velocity change beneath Jiuyi River and its surrounding area may be closely related to the corresponding regional fault structure and seismic activity; (3) the upper crust of Sandouping area For high-speed, indicating that the Three Gorges Dam area in a stable area.