Abstract: We have made a study to the piedmont fault zone of Taihang Mountain based on geological and geophysical data of recent years. Our new insights suggest that this fault zone began to emerge in Mesozoic and formed mainly in Early Tertiary. It consists of a series of NE-NNE strike faults, which were arranged obligue in a left-lateral manner. Its structures and activities have evident segmentation. Along the middle and north segment, the faults, such as the Baoding-Shijiazhuang fualt, are of large detachment faults. They stretch about 70km horizontally in the tilt direction with horizontal offsets of 17km and vertical offset of 5000-6000m during Early Tertiary. This fault zone belongs to the detachment structure in the upper crust rather than a deep fault. It has weak activities since Quaternary and has no direct cause relation with major earthquakes. It is, however, still somewhat of importance to studies of regional seismotectonics and earthquake prediction, because both the south and north section of this fault zone intersect with other seismic zones which have different strikes.

Key words: Detachment fault, Rift basin, Taihang Mountain

摘要： 据近年来的地质和地球物理资料对太行山山前断裂带做了研究,得到一些新的认识。断裂带开始出现于中生代,主要形成于早第三纪,由一系列NE-NNE向断裂左型斜列组成。断裂带的结构构造和活动具有鲜明的分段性,中北段的保定-石家庄等断裂为大型拆离断裂,在倾向上水平延伸70km左右,早第三纪水平拉张断距约17km,垂直断距5000～6000m。断裂带基本上是发育于上地壳的拆离滑脱构造,不属深大断裂。它第四纪活动性不强,与强震活动没有直接成因关系,但断裂带南、北两部分与其它走向的地震构造带交汇,对区域地震构造和地震预测研究仍有重要意义。

关键词: 拆离断裂, 裂陷盆地, 太行山