华北盆地北缘香河—皇庄断裂晚更新世以来活动性研究

香河—皇庄断裂位于华北盆地北缘，是京津唐地区一条重要的NE向断裂构造。浅层人工地震反射剖面探测发现，香河—皇庄断裂在廊坊市香河县西马家窝地区表现为一条NE－SW走向的NW倾正断层，剖面上呈铲状，上部略陡，向下逐渐变缓；其对大厂凹陷东缘没有明显的控制作用，为一条新近纪以来形成的断裂，切穿了前中生界基底，且第四纪以来仍有活动。通过部署于断层两侧的构造观察孔岩芯对比及测年数据判断，(6.69±5.6) ka以来香河—皇庄断裂无活动，其上断点很可能位于距地表15～30 m范围内，大致相当于晚更新世早期；在中更新世上部地层中，香河—皇庄断裂存在1.5～1.8 m的垂直落差。香河—皇庄断裂现阶段处于不活动状态，未来发生中强地震的可能性较低。

Activity of the Xianghe-Huangzhuang fault in the northern margin of the North China Basin since the Late Pleistocene

The Xianghe-Huangzhuang fault, located in the northern margin of the North China Basin, is an important NE-trending fault in the Beijing-Tianjin-Tangshan area. Based on the data of artificial shallow seismic reflection profiles, the Xianghe-Huangzhuang fault in the Ximajiawo area of Xianghe County is a NE-SW trending normal fault with a spade-shaped profile, and the upper part is slightly steep and gradually slows down. The Xianghe-Huangzhuang fault, which was still active in the Quaternary, is a new fault formed in the Neogene and cuts through the basement of the pre-Mesozoic. However, there is no obvious evidence that the fault has a controlling effect on the eastern margin of the Dachang Depression. Judging from the comparison between the cores of two structural observation boreholes on both sides of the fault and the data of ¹⁴C dating and optically stimulated luminescence (OSL) dating, since (6.69±5.6) ka, the Xianghe-Huangzhuang fault has been inactive, and the upper breakpoint of the fault is approximately 15-30 m away from the surface, which is roughly equivalent to the early Late Pleistocene. In the upper strata of the Middle Pleistocene, the fault has a vertical displacement of 1.5-1.8 m. At present, the Xianghe-Huangzhuang fault is inactive, and the possibility of inducing moderate and large earthquakes is low.