Abstract: The Kunlunshan M_S 8.1 earthquake of Nov.14,2001 is the biggest seismic event in China's continent in the past five decades. For this event,some researchers have developed an analysis method of brightness temperature difference inside and outside the Eastern Kunlun Fault,and have drawn an important conclusion. They found that before the earthquake (beginning from Oct.2001),the brightness temperature along the seismogenic fault became higher than that outside the fault,and affirmed that this phenomenon was the impending precursor of the 2001 Kunlunshan M_S 8.1 earthquake. However,our comparison study on the IR images of 2001 with those of 1999 has revealed that the same phenomenon has occurred also in 1999,in which no earthquake has been recorded. The Eastern Kunlun Fault is interpreted and analyzed by using NOAA thermal infrared (IR) remote sensing images combining with numerical processing of IR brightness temperature. The comparison of IR images in seismically quiet period of 1999 with those before and after the Kunlunshan M_S 8.1 earthquake in 2001 has indicated that seasonal meteorological factor greatly affects the change of IR images along seismogenic fault. In early winter,the IR brightness temperature along the fault is equal or even higher than that outside the fault. Moreover,the comparison between brightness temperature along the Eastern Kunlun Fault and along the Altyn Tagh Fault has also revealed that during the transitional period between autumn and winter,the disturbance of meteorological factors on ground surface are significantly greater than the IR of ground object itself. We suggest,therefore,that the anomalous increase of ground temperature before the occurrence of the M_S 8.1 Kunlunshan earthquake on Nov.14,2001 incorporated natural phenomenon of seasonal change,while the identification of anomaly related to earthquake needs a further study.

Key words: Eastern Kunlun Fault, thermal infrared RS, meteorological factor, impending precursor

摘要： 利用NOAA卫星热红外遥感图像对东昆仑断裂带进行解译分析,并结合红外亮温的数值化处理,对比研究了地震活动比较平静的1999年和2001年昆仑山8.1级地震前后的资料。结果表明,季节性的气象因素对断裂带的影响很大。在初冬季节,断裂带内的红外亮温值等于甚至高于周围环境温度。同时对比分析东昆仑断裂与阿尔金断裂的亮度温度也发现,在秋冬季的季节过渡期,气象因素对不同地物热惯量的影响很大。因此认为,前人提出的2001年11月14日发生在东昆仑断裂带上的8.1级地震的震前红外辐射的增温异常,其中包含了随季节变化的自然现象,与地震有关的异常信息还有待于进一步探讨。

关键词: 东昆仑断裂, 卫星热红外, 气象因素, 临震异常