///Some typical precursory anomalies recorded by stations in oft-com:office:smarttags" />Qinghai, Gansu, Sichuan, Xinjiang, Ningxia, Hebei and Shaanxi Provinces (Regions) are collected and checked before MS8.1 earthquake in west of Kunlun Mountains Pass. According to the standards of examples of earthquakes in China, the earthquake precursory anomalies criteria are determined, and 53 precursory anomalies are distinguished. The characteristics of these anomalies before MS8.1 earthquake are analyzed, and the results show that the earthquake influence area is very large. The farthest precursory anomalies recorded by instruments are 2 900 km far away, and in the paper the distance is found to be 2 100 km. And the results also show that anomalies presented characteristics of long time, multiple items and large amplitude. The authors believe that large earthquake monitoring should take into account the data of a larger area, even some thousand kilometer area with much more denser earthquake array.
