Characteristics of Seismicity Anomalies before M_S8.1 Earthquake at the West to Kunlun Mountain Pass

The seismicity anomalies before MS 8.1 earthquake at the west to Kunlun Mountain pass in 2001 are studied by using the methods of tracing dynamic seismicity evolution patterns,the parameters time scanning and earthquake swarm determination,which are all commonly used in earthquake prediction. The results show that the seismicity anomalies were obviously in order,the anomalies for earthquake gaps,belts and groups appeared in same period.It is considere that the evolution of earthquake gaps patterns is helpful to study the large earthquake prepare field,the earthquake swarm are precursory reflect of mult-points stress releasing before large earthquake,and large earthquake could be predicted in middle and short-term through synthesis analysis to the seismicity parameters time scanning.