与地震有关的活动断裂带红外辐射变化特征

Variation characteristics in infrared radiation of active fault zone related to earthquakes

为了获得与地震有关的活动断裂带红外辐射变化信息,以2010年4月14日青海省玉树Ms 7.1级地震为研究对象,利用MODIS热红外波段遥感数据研究了地震前后发震构造甘孜—玉树断裂带的亮温演化特征,分析了地震发生当月每10 d亮温变化情况,并与2011年同期该断裂带的亮温特征进行对比。结果表明:地震前一个月内,断裂带附近亮温值偏高,亮温变化最为显著的区域出现在断裂带北端,与野外考察获得的本次地震地表破裂带位置相吻合;震后7～16 d,断裂带附近出现了明显的亮温增高现象,结合地震发生时水汽及CO变化情况,认为这一亮温增高现象与震后地下气体的大量释放有关;2011年5月断裂带附近的亮温高值可能与同年6月发生的Ms 5.3级囊谦地震有关。因此认为,断裂带亮温的显著变化对断裂活动有一定指示作用,利用热红外遥感数据研究主要断裂带红外辐射特征,对地震构造带活动性监测具有重要意义。

The brightness temperature variation along the Ganzi -Yushu fault before and after 2010 Ms 7.1 Yushu earthquake was analyzed using MODIS data so as to obtain the infrared radiation variation information of the active fault related to the earthquake. It is shown that the value of the brightness temperature in one month before the earthquake was higher than that of other periods. The maximum variation was loeated at the northern end of the fault, where surfaee ruptures were found by field investigation. The obvious increase of brightness temperature was found during the 7 - 16 days after this event through an analysis of the data obtained from the seismic month at 10 day interval, and this might have had some relationship with the degassing of vapor and CO along the faults during the earthquake. For comparison, the data obtained in the same period of 2011 were analyzed. The results indicate that the brightness temperature of Ganzi - Yushu fault showed a homogeneous belt during the non - seismic time. The increase in brightness temperature of this fault was also found in May which might have had relationship with the Ms 5.3 Nangqian earthquake that oceurred on June 26, 2011. It ean be eoneluded that the variation of brightness temperature related to the fault zone can serve as an indicator of the fault aetivities. The study of the infrared radiation variation of main faults using satellite data is therefore significant for the monitoring of the seismic tectonie activity.