辽宁地区ML≥5．0地震前中等地震集中活动的震兆研究

Research on the precursor of medium earthquake （ML≥5.0） activities in Liaoning Province

定义了描述中等地震活动增强的3个参量E、T和R，通过对辽宁地区13次ML≥5．0地震的统计分析，结果显示，辽宁地区Mi≥5．0地震前确实存在中等地震活动增强的现象，且主震77％发生在中等地震增强活动中的最后一次中等地震后3个月内，震中距离第一次或最后一次中等地震震中约5～70km，概率80％。震级与中等地震增强活动参数E，T，R有关。

In this paper, with statistics analysis of 13 earthquakes （ML≥5.0） in Liaoning Province, three parameters （E, T, and R）, which are used to describe the activities of medium earthquakes are defined. The final result shows that the frequency of medium earthquakes become higher before each main earthquake （ML≥5.0） occurred in Liaoning Province. It also shows that 77% of the main earthquakes occurred in 3 months since the last medium earthquake of those medium earthquake activities, and 80% of the main earthquake epicenters are located in the range of 5-70 km around the first/last medium earthquake epicenter. The magnitude of main earthquake is relative with parameter E, T, and R of medium earthquake activities.