2012年云南宁蒗5.7级地震前兆异常特征

Precursory Anomaly Characteristics of the 2012 Ninglang,Yunnan M5.7 Earthquake

以2012年6月24日宁蒗5.7级地震为例,结合滇西北地区其他地震的前兆反映,对地震前永胜、丽江、云龙、楚雄、弥渡、洱源等台站前兆仪器记录到的不同程度异常信息特征进行综合分析,发现这些异常不仅有清晰的短临指标和明显的同步性,一些异常还有完整的短期变化过程。依据这些异常形态、异常幅度、异常持续时间及成因,异常特征基本上可以归纳为3种类型:即震前持续、震后恢复的短期趋势异常;同步性的短临异常;"震前扰动"短临及临震异常。

Taking the Ninglang M5.7 earthquake on June 24, 2012 as an example, and combining with the precursor reflections of other earthquakes in Northwestern Yunnan, the characteristics of anomalous information recorded by precursor instruments at Yongsheng, Lijiang, Yunlong, Chuxiong, Midu and Eryuan stations before the earthquake were comprehensively analyzed. It is found that these anomalies not only have clear short-impending indicators and obvious synchronization, but also have complete short-term change processes. According to these anomalous forms,anomalous amplitudes, anomalous duration and causes, the anomalous characteristics can be basically summarized into three types: short-term anomalies of pre-earthquake continuity and post-earthquake recovery;impending earthquake anomalies of synchronism;short-term and impending earthquake anomalies of 'pre-earthquake disturbance'.