Abstract: A certain relationship between ground tilt and the location of earthquake generation has been found, that is, there are some regular distributions of ground tilt direction before occurrence of strong earthquakes. In this paper, the distribution of ground tilt direction before Zhangbei earthquake with M6.2 has been studied, and the result shows that most of the direction lines met in the epicenter area before the earthquake. Thus we try to find a method to determine the earthquake generation area before the earthquake occurrence, based on the data before august 2004. The direction distribution of ground tilt in the areas of North China, Xinjiang and Sichuan-Yunnan is analyzed and discussed. In North China, some tilt direction lines met in Beijing, Tianjin and Tangshan area, some met in Shanxi belt. The area is large and separated, and it is hard to find a remarkable anomalous area. In Xinjiang and Sichuan-Yunnan area, we cannot find similar remarkable abnormal area like that before Zhangbei earthquake either. Thus, there are no spatially anomalous characteristics of strong earthquakes in the above-mentioned areas before August 2004.

Key words: Crustal deformation, Ground tilt, Earthquake precursor, Anomaly, Epicenter