昌平-丰南断裂构造浅层地震勘探新证据

昌平-丰南断裂是根据卫星遥感图像解译发现的一条隐伏活动断层，是NWW向张家口-蓬莱断裂带中规模最大的断裂，为进一步调查确认断裂的存在、空间位置、性质和断裂构造特征，并重新厘定其活动性，在卫星遥感影像解译断裂大体空间位置的基础上，布设了2条浅层地震勘探测线，对昌平-丰南断裂进行了高分辨率地震勘探，获得了测线控制范围内地下结构和断裂构造的清晰成像。结果表明，昌平-丰南断是一条倾向S、走向NWW的走滑正断层，浅层地震剖面揭示断层上断点埋深80~100 m，断错了上更新统底界，结合测线附近钻孔资料推测其最新活动时代为晚更新世。

New Evidences of the Changping-Fengnan Fault Discovered by Shallow Seismic Exploration Method

The Changping-Fengnan fault is the largest fault in the Zhangjiakou-Penglai fault zone. It is a buried active fault discovered through interpretation of satellite remote sensing images. The study of the Quaternary activity of the Fengnan-Fengnan fault is of great significance to understand the activity characteristics of the Zhangjiakou-Penglai fault zone. To further investigate and confirm the existence, spatial position, property, and tectonic features of the Changping-Fengnan fault, based on the interpretation of satellite remote sensing images of the general spatial position of the fault, two shallow seismic survey lines were laid for high-resolution seismic exploration. Using the abovementioned working methods and selecting the appropriate data processing techniques, the clear imaging of underground structure and fault structure within the control range of the survey line were obtained. The results showed that the Changping-Fengnan fault is an S- and NWW-trending strike-slip normal fault. The shallow seismic profile reveals that the buried depth of the fault is 80-100 m, and the latest active age is estimated to be late Pleistocene based on the borehole data near the survey line. By interpreting the deep seismic reflection data across the Changping-Fengnan fault, the deep structural features of the fault are obtained, and the Mesozoic and Paleozoic strata and crystalline basement were dislocated downward. The results of this paper provide reliable seismological data for the evaluation of the existence and activity of the Changping-Fengnan fault.