Comparative study on abnormal seismicities before Zhangbei Earthquake and Datong earthquake

In this paper, we studied the long, mid- and short-term abnormal seismicities before Zhangbei and Datong earthquakes in North China. We found that there were a lot of similar abnormal seismicities and attempted to explain them. We suggest that the reason of the similar abnormal seismicities was the Datong earthquake and Zhangbei earthquake, related to Shanxi tectonic zone and Zhangjiakou-Bohai tectonic zone. Similar tectonic environment resulted in these similar abnormal phenomena.