This paper deals with the distribution of trace gases, such as H₂, Hg, Rn, CO₂ on the faults by means of analysis of the gases in the faults of the northeastern part of Arerjin Fault starting from Annanba Dam in the west and ending in the road of Changma in the east. The research pointed out that on the same profile, the concentration of the four kinds of gases not only have the syneronous change but also have some to do with the activity strength of the faults. In addition, the analysis shows that the concentration of the gases(H₂, Hg, Rn, CO₂) is trending to be higher in the west but lower in the east, which is accorded with the strong activity in the west and weak in the east for the faults.
This paper also discusses how to judge the dynamic state and how to predict the short-term and impending earthquakes by means of gas fixing point and gas periodical observation, pointing out that it is a practical method to make use of gas to study the activities of faults.