here are many differences of seismicities between the ZhangbeiShangyi earthquake and DatongYanggao earthquake, although the distance is less than 150km between the epicenters of them.

) beneath the ZhangbeiShangyi earthquake area, which belongs to Inner Mongolia geoaxes, has the nature of a transition zone as compared to its surrounding regions, Yanshan mountain fold belt, rifting basin of North China, rift system of Shanxi province and Erdos block.

The ZhangbeiShangyi earthquake of January 1998 occurred just at the central area confined by Zhangjiakou, Shangdu and Jining.

After the occurrence of the Zhangbei-Shangyi earthquake sequence,the hypocentral locations given by different agencies were diverse and the hypocentral distribution of the aftershocks showed no dominate orientation, and the seismogenic.

The study On the anomalies of subsurface flulds occurred before Zhangbei-Shangyi earthquake in northern part of China (110°～ 12O°E ， 38°～42°N) shows that: ①There are a　large number of subsurface fluid anoma1ies before this earthquake, and there are more physical anomalies than chemical anomalies.

The characteristics of CO2 precursory anomalies , which were observed in 9 earthquakes (M ≥4) in Houhaoyao, Huailai county for last 7 years, are analyzed- Forty-seven days before the Zhangbei-Shangyi earthquake，an anomaly of abrupt increase in CO2 in fault gas was observed.

After Zhangbei Shangyi earthquake(1998,1,10),Beijing Telemetered Seismic Network(BTSN) arranged three microseismographs in the meizoseismal area during 10～20,Jan.

Wavelet analysis as a tool for revealing geomagnetic precursors of the Zhangbei earthquake;

Research of the field of subsurface fluid anomalies before the Zhangbei earthquake;

Continuous monitoring of focal medium parameters and their changed before Zhangbei earthquake;