关键词: 断层, 异常, 活动方式, 震前, 华北地区

Abstract: In this paper, the authors have analyzed the cross-fault mobile geodetic deformation data and studied the pattern of the fault movement before the Tangshan, Datong and Zhangbei earthquakes. It is considered that faults have remarkable anomalous movement before earthquakes. It is considered that faults have remarkable anomalous movement before earthquakes. The anomalous pattern of the fault movement is of the tectonically controlled feature and also related to seismogenic mechanism. In the process of earthquake preparation, multiple stress concentration may occur. From the distribution of fault irreversible anomalous movement, we have inferred that the Tangshan earthquake has eased up the seismic risk in Yanqing-Huailai area, and the Datong earthquake eased off the seismic risk along Zijingguan-Langshan fault zone. The anomalous fault movement of the Zhangbei earthquake offered relaxation variation. The tendency of seismic risk in the Capital circle and its neighboring area will be relaxed.

Key words: Fault, Anomaly, Movement pattern, Pre-Earthquake, North China region