【摘要】 本文分析了１９９１─１９９２年云南西部缅甸境内４次Ｍｓ≥６．８级地震前，距震中３００─８００公里的云南地震台站观测到的前兆异常。研究认为，这些异常具有中期和短临异常性质，并具有异常时间同步、中期异常向短期阶段过渡、特征清楚等特点。作者将距震中３００─８００公里内的异常变化与多次７级地震震例中震源区的异常进行比较，发现其异常形态及中期异常向短期阶段转折的特征甚为相拟，因而认为这些异常是地震前兆。最后对这些异常出现的机理进行了解释。更多还原

【Abstract】 Precursory anomalies observed in Yunnan stations, 300-800km away from the epicenters of 4 earthquakes with Ms≥6.8 during the period of 1991-1992 in Burma located in west of Yunnan, have been studied in this paper. The study shows that these anomalies have medium-term, short-term and impending features. Furthermore, these anomalies are simultanious with characteristics of transition from medium-term anomaly to short-term stage. The authors checked the anomalous variations 300-800km away from epicenters with focul area anomalies of many M≥7 earthquakes and found that the features of anomalous forms and transition from medium-term to short-term stage are much similar. So, these anomalies are considered as earthquake precursors. Finally, the mechanism of these anomaly occurrences have been interpreted in the paper.更多还原