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利用架设在沧州地区的20台流动地震台站于2006年12月至2010年7月间记录的271个远震事件,读取的2308个P波到时数据,采用地震层析成像方法反演得到沧州及其邻区(38.0°N～39.0°N,116.5°E～117.5°E)的地壳上地幔P波三维速度结构。层析成像结果表明,沧东断裂两侧的地壳介质的速度分布表现出明显的横向差异,浅层速度分布同地表地质结构分布相一致。沧东断裂西北侧沧县隆起的地壳速度较高,表明其基底抬升;断裂带东南边的黄骅拗陷速度较低,说明基底埋藏较深。本文的远震层析成像研究结果和前人使用重力、电磁和人工地震的探测结果都表明,沧东断裂带两侧的地质构造和地球物理性质有明显的变化,这种构造差异在整个地壳中都有体现。
Using 271 teleseismic events recorded by 20 mobile seismic stations located in Cangzhou from December 2006 to July 2010, 2308 P-wave arrival data were retrieved and retrieved by seismic tomography The 3-D velocity structure of the crust and upper mantle in Cangzhou and its adjacent areas (38.0 ° N ~ 39.0 ° N, 116.5 ° E ~ 117.5 ° E) was obtained. Tomographic imaging results show that the velocity distribution of crustal media on both sides of Cangdong fault shows a significant horizontal difference, and the distribution of shallow velocity is consistent with that of surface geological structure. The high crustal velocity of Cangxian uplift on the northwestern side of Cangdong fault indicates that its basement is uplifted; the Huanghua depression in the southeast of the fault zone is low, indicating a deeper buried basement. The results of teleseismic tomography and the results of previous studies using gravity, electromagnetism and artificial earthquakes all indicate that the geological structures and geophysical properties on both sides of the Cangdong fault zone have obviously changed. The tectonic differences between the whole crust In both have reflected.