断裂带内外温差法在震前红外异常研究中的应用

APPLICATION OF THE INSIDE-OUTSIDE TEMPERATURE RELATION ANALYSIS METHOD IN STUDY ON SATELLITE INFRARED ANOMALIES PRIOR TO EARTHQUAKE

以2000年姚安MS6.5地震、1997年玛尼MS7.5地震为例,应用断裂带内外卫星红外亮温差(下文简称亮温差)值分析法,研究震中附近活动断裂上震前卫星红外异常的时间演化过程。分析结果表明,在正常时期红河断裂带内外的亮温差值在0～1.5℃范围内波动,而在异常表现很强烈的时段,沿红河断裂带内外的亮温差达到3℃以上,比正常时期高出2℃左右。通过对1997年11月8日玛尼7.5级地震发震断裂——马尔盖茶卡断层东段1996,1997,1998年3年带内平均值和带内外的亮温差值的对比研究发现,由于受大面积降雪的影响,1997年10月初至11月中旬,断裂带内平均亮温比1996和1998年同期亮温都要低,但断裂带内外亮温差值却比1996和1998年同期高出2～3℃左右。地震之后相对亮温差很快回到正常状态。运用同样的方法对华北和川滇近几年未发生强震的几条重要的活动断裂带的卫星红外亮温特征进行了研究,未发现类似震前红外异常的情况。

The Yaoan Ms 6.5 earthquake on Jan. 15,2000 and Mani Ms 7.5 earthquake on Nov. 8,1997 are taken as cases to study the temporal process of the satellite infrared anomalies on the active faults near the epicenter. The inside-outside temperature relation analysis method （IOTRAM）was used in the middle segment of the Red River Fault. The result shows that the inside temperature is about 0 - 1.5℃ higher than the outside temperature in the normal periods. But the brightness temperature inside the Red River Fault is 2 -3℃ higher than that outside the fault 15 days before the Yaoan Ms 6.5 earthquake on Jan. 15,2000. The Mani Ms 7.5 earthquake occurred on Nov. 8,1997 in northern Qingzang-Tibetan plateau. Curves of the average brightness temperature in the east section of the Margaichaca fault belt and the difference inside and outside the region of the fault belt in 1996,1997 and 1998 were contrasted. The result shows that temperature difference in Oct. and Nov. in 1997 was 2 - 3℃ higher than that in 1996 and 1998 ,though the inside temperature in the same term in 1997 was the lowest in the three years because of a heavy snow. It returned to normal after earthquake. IOTRAM was used to study the active faults in Huabei and Chuandian regions where less earthquakes have occurred recently and no infrared anomalies appeared.