对陕西宝鸡地区“高家村—高店断裂”的新认识

New Recognition on“Gaojiacun-Gaodian Fault”in Baoji Area of Shaanxi

为进一步查明陕西宝鸡地区"高家村—高店断裂"地表详细分布状态及其活动性,在前人调查研究成果的基础上,对该"断裂"进行了1∶10 000野外地质地貌填图,并针对支持该"断裂"地表现代活动的几处关键证据(包括咀头剖面、桐峪河探槽剖面、杨家店探槽剖面、唐家塬探槽剖面、姬家店剖面)进行了详细的剥土清理、探槽施工和浅层地震勘探等工程查证。结果表明:咀头剖面反映的断层活动证据并不存在,前人认为的断层活动断面实际为该处一滑坡体后缘残余的滑动错落面;桐峪河探槽剖面中的断层活动断面也不存在,前人剖面中显示的断层错断面只是一处古河床边岸侵蚀面;杨家店探槽剖面内的3条主断面可能为与滑坡有关的滑动面,探槽两侧附近也没有断层存在的证据;唐家塬探槽剖面展示的断面仅仅为台塬脚下滑坡的滑动面;继续向西至"高家村—高店断裂"通过的姬家店剖面一带,所谓的断层陡坎仅是二级阶地前缘;西崖村—半沟村一带的浅层地震勘探结果也不支持断面深部存在的可能。因此,所谓的"高家村—高店断裂"并不存在。

On the basis of investigation and achievements by predecessor, a geological and geomorphologic map with the scale of 1： 10 000 for ＂Gaojiacun-Gaodian fault＂ in Baoji area of Shaanxi was conducted in order to further find out its surface distribution and activity. The engineering investigations including capping clean, trench construction and shallow seismic prospecting were used to re-verify the several key evidences including Zuitou profile, Tongyuhe trench profile, Yangjiadian trench profile, Tangjiayuan trench profile and Jijiadian profile, which showed the present activity of the ＂fault＂. The results show that fault activity evidences reflected by Zuitou profile does not exist, and the fault activity surface measured by predecessor is residual slide scattered surface in back margin of a landslide fault activity surface in Tongyuhe trench profile also does not exist, and the fault surface measured by predecessor is actually a erosion surface of ancient riverbed the three main fault surfaces in Yangjiadian trench profile may be the sliding surfaces caused by landslide, and there is no evidence for the existence of fault aroundboth sides the fault surface in Tangjiayuan trench profile is nothing but slide surface in the foot of platform ＂Gaojiacun-Gaodian fault＂ crosses the Jijiadian profile westward, the so-called fault scarp is actually the front edge of the second terrace shallow seismic prospecting in XiyacunBangoucun area also reveals the inexistence of the ＂fault＂ in deep. Therefore, the so-called ＂Gaojiacun-Gaodian fault＂ does not exist.