磁县大名断层分段特征及活动性

根据邯郸市活断层探测的最新资料,结合野外调查和石油地质的研究成果,对磁县—大名断层的分段性进行了研究;根据探槽开挖及测年结果的分析,对其活动性进行了讨论。研究结果显示,磁县—大名断层从东向西可分为3段:大名—临漳段、磁县—峰峰段和南山村—岔口段,3段呈左阶展布。研究表明:磁县—峰峰段晚更新世以来没有活动的证据;西段活动性较强;大名—临漳段沿线有多次中强震发生,其活动性有待进一步研究。由于上覆沉积层的影响,磁县—峰峰段未见明显的地表破裂带,因沉积物厚度逐渐减薄而表现为上断点由东向西逐渐变浅,在南山村—岔口段表现为明显的地表破裂带。

Segmentation Characteristics and Activity of Cixian-Daming Fault

Based on analysis of the latest data obtained from the project of active fault surveying in Handan city, combined with field investigation and the explanation of seismic profile from oilfield, the segmentation of Cixian--Daming fault is studied. According to analysis of digging trench and testing sample＇s age, we discuss the activity of Cixian--Daming fault. It is shown that Cixian--Darning fault is divided into 3 segments, which are Daming-- Linzhang segment, Cixian-- Fengfeng segment and Nanshancun-- Chakou segment. It can be deduced that the activity of middle segment of Cixian--Daming fault is steady since late Pleistocene based on the result of sample＇s ages, while the activity of west segment is active based on to- pography investigation and the latest study, which was surface fracture belt formed by the earthquake occurred in 1830. According to geological data of oilfield, the depth of Daming--Linzhang segment is buried deeply to 1200m. Even so, its activity should be studied because of a few earthquakes occurred along the fault. Surface fracture belt cannot be found along Cixian--Fengfeng segment for thick upper sediment. The depth of each upper breakpoint gradually turns shallow because of the thickness of the upper sediment turning thin. Therefore surface fracture belt can be easily found along Nanshancun--Chakou segment.