万全断裂的几何结构和活动特征

本文根据实地调查和探测资料对万全断裂的几何结构和构造活动进行分析与研究,结果表明：该断裂是洋河盆地北缘断裂带的组成断裂之一,由南、北两段斜列组成,呈北东-北北东走向展布,为正断层,长约15km;断裂在第四纪期间持续活动,控制着附近地区的构造演化和地貌发育：西北侧中生代地层抬升,形成低山丘陵;东南侧地块下降,接受第四纪堆积,构成山间盆地;晚更新世以来单条断层的平均垂直活动速率大于0.03—0.3mm/a。

Geometric Structure and Tectonic Activities of Wanquan Fault, Hebei Province

Based on detailed investigations and geophysical prospecting, we study the geometrical characteristics and tectonic activities of Wanquan fault in northwest of Beijing in this paper. This fault strikes mainly northeast or northeast to north, dipping to southeast, and extends over a length of 15km. It is a major geological and geomorphic margin, controlling the neotectonic movement in this region. On the southeast side of Wanquan fault there is Late Quaternary unconsolidated deposits, forming basin or deposition; hut on the other side there is Mesozoic volcano debris, forming lower- mountains and hills. Wanquan fault is a normal fault with southeast-dipping of medium-high-angle. This fault is active in Quaternary. Since the middle-late time of late Pleistocene, the average rate with vertical slip of single fault is about 0.03—0.3mm/a, but the fault has multiple slipping surfaces, and a total large-rate with vertical slip will be estimated.