2010年玉树Ms7.1级地震前热红外异常特征研究

STUDY OF VARIATION CHARACTERISTICS OF SATELLITE THERMAL INFRARED BRIGHTNESS TEMPERATURE BEFORE YUSHU Ms7.1 EARTHQUAKE IN 2010

以静止卫星热红外相当黑体亮温为数据源（2005~2011年）,应用功率谱相对变化法对2010年青海玉树Ms7.1级地震进行了分析,结果显示：地震前相对功率谱比值出现明显增强,特征周期为13天。异常沿北东方向扩展,大致与该区域甘孜—玉树断裂带呈斜交状,异常比值和异常面积范围在2010年4月5日（震前10天）达到最大,异常比值超过4的范围约达4万平方千米。热红外亮温相对功率谱比值明显受到活动断裂控制。随着震中距增加,该比值在震前3天均值下降幅度比震前20天、震前30天的均值都要快。

The thermal infrared images features are analyzed by using Black Body Temperature （TBB） data of 2005 -2011 from geostationary satellite to research Yushu Ms7.1 earthquake in 2010 by estimating relative variance rate of power spectrum. The results show that the power spectrum amplitude increased before the earthquake. The characteristic period is about 13 days. The extreme areas of power spectrum amplitude values over 4 reached 40 000 square kilometers approximately. The relationship between abnormal over direction and the regional strike of fault is oblique crossing. The power spectrum amplitude values are obviously controlled by active faults. Before the earthquake, characteristic power spectrum amplitude reached relatively the maxi- mum （5.41） at the Ganzi- Yushu Fault （F1 ） of the southern boundary of the Bayankala block. Recent research shows that the values were about the same level as the F1 fault, perhaps slightly less at Kunlun mountain - Dari fault（ F2 ）. Accordingly, the values reduced to 3 roughly at the East Kunlun fault （ F3 ）. To sum up, with increasing the epicenter distance, the power spectrum amplitude of 3 days average values decreased faster than the 20 days average values and 30 days average values before the earthquake.