Abstract: The baseline and level data for 36 years at Dahuichang observation site are systematically studied in this paper. These observation data are resolved into horizontal and vertical components of fault slip. Based on the relation between fault slip and the direction of compressional stress in North China, we reveal the stress regimes and faulting characteristics among Babaoshan Fault Zone (Dahuichang segment) during the periods of Xingtai, Tangshan and Zhangbei-Datong earthquakes. We conclude that study on the deformation data should be carried out not only by mathematic processing and statistics analysis, but also by geological interpretation based on faulting pattern and stress regimes, in order to understand how fault slips during the development of earthquakes.

Key words: Deformation measurement across the fault, Active pattern of fault, Stress state