中、强震前川滇块体遥感红外辐射异常分析——以宁蒗M5.7地震和鲁甸M6.5地震为例

Anomalies of Thermal-Infrared Radiation Based on Remote Sensing in the Sichuan-Yunnan Block before Medium to Strong Earthquakes:a Case Study of Ninglang M5.7 and Ludian M6.5 Earthquakes

许多研究表明中强地震前出现了红外辐射异常。近年来,川滇块体中、强地震频发,利用遥感数据对其红外辐射异常变化开展深入分析十分必要。结合13年MODIS/Terra遥感红外数据,采用空间距平分析法、辐射增强阈值面积指数法及辐射亮温均值低频时间序列法,对2004年4月—2017年6月红外亮温数据进行深入分析,研究川滇块体及周边构造断裂M≥5.5地震的震前异常信息。结果表明:(1)M≥6.0地震在震前3~6个月川滇块体会出现较为明显的红外辐射增强异常现象;(2)震前红外异常并非随机分布,而可能是受到相关块体的控制;(3)以宁蒗M5.7地震和鲁甸M6.5地震为例研究发现,震前辐射增强较高的小范围区域与震中位置存在一定关联。

Some researches have shown the existence of thermal-infrared radiation anomalies before moderate to strong earthquakes.Sichuan-Yunnan Block has been considered in this study due to the occurrence of frequent moderate to strong earthquakes in recent years.In Sichuan-Yunnan Block,anomalies analysis of the thermal-infrared radiation based on remote sensing is essential and significant.We used the moderate resolution imaging spectroradiometer(MODIS)or terra thermal-infrared data from April 2004 to June 2017 to analyze the thermal-infrared radiation anomalies in detail.Then,we researched the thermal-infrared anomalies before M≥5.5 earthquakes occurred in Sichuan-Yunnan Block.The results showed that:(1)obvious anomalies of thermal-infrared radiation appeared before the M≥6.0 earthquakes occurred in the study area;(2)infrared anomalies appeared before earthquakes are not randomly distributed,but are restricted by related blocks;and(3)researches on Ninglang M5.7 earthquake and Ludian M6.5 earthquake indicate the correlation between the epicenter and the region of enhanced radiation before the earthquakes occurred.