四川青川M_L≥4.0地震前小震短临活动特征

Research on the short-term precursor activities of smaller earthquakes before M_L≥4.0 in Qingchuan,Sichuan Province

统计2009年1月1日至2011年10月30日四川青川县内8 000多个M_L≥1.0地震,研究汶川地震后青川县内小震活动的日频次变化和前兆起伏加剧、突跳,与其后48小时内发生的M_L≥4.0中强震的对应关系,结果对青川县中强地震发生时间、空间范围的预报分析有一定意义。

In this article the minor earthquakes ML≥1. 0 in Qingchuan during the period from January 2009 to October 2011 was statistically studied. The result indicates that before a main shock of ML≥4. 0, a series of minor events in the 48 hours and distances away from epicenters for the ML≥4.0 events performance anomaly of daily frequency and premonitory fluctuation aggravation. The results show that the mutual features exist aboard in special, temporal and intensity before the main shock, and they have a practice value for analysis and diagnosis in local earthquake prediction in Qingchuan.