昆仑山口西8．1级地震的远场前兆异常特征

Characteristics of Far Field Precursory Anomalies Before M_S8.1 Earthquake in West of Kunlun Mountains Pass

收集并核实了昆仑山口西8.1级地震前青海、甘肃、四川、新疆、宁夏、河北及陕西等省前兆台网记录到的一些典型的前兆观测异常,按照中国震例总结研究的规范,确定了地震前兆异常判定准则,判定出前兆异常53项。本文在系统分析昆仑山口西8.1级地震前兆异常特征后认为,该次地震的孕育影响场具广域性特征,仪器记录的前兆异常范围直径达到2900km,本文判定的前兆异常范围直径达2100km。并且出现异常的时间长、测项多、幅度大。研究认为特大地震的监测工作应该考虑大区域(数千公里)范围的资料变化,在多震区还需有较密的观测台网。

Some typical precursory anomalies recorded by stations in 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 2900km far away, and in the paper the distance is found to be 2100km. 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 a some thousand kilometer area with much more dense earthquake array.