2016年12月8日新疆呼图壁县M_s6.2地震前热红外亮温异常分析

Anomalies of Thermal Infrared Brightness Temperature during the 2016 Hutubi M_s6.2 Earthquake in Xinjiang

以2016年12月8日新疆昌吉州呼图壁县M_s6. 2地震为实际研究对象,选择FY-2E静止气象卫星每小时亮度温度产品数据,利用功率谱相对变化法提取出地震前后亮温异常时空变化.然后,提出了时间窗口移动平滑方法来提取热红外异常指数,利用该指数提取了地震前后地表热红外异常的时空分布.经对比分析,发现2种方法均能有效提取出地震前后亮温异常变化情况,并且其变化发展的趋势相类似,但热红外异常对应的发生时间和持续周期则有所差异.综合2种方法可知,新疆呼图壁县M_s6. 2地震发生30 d之前存在一个持续时间长达10 d以上的热红外异常增温期,然后在临震时又有一个热红外异常增温期,其趋势呈逐渐增强,在震后的数天内达到峰值,然后逐渐减弱消失.

In order to analyze the possible thermal infrared anomalies in the epicentral area of Hutubi Ms6.2 earthquake occurred on December 8, 2016, the brightness temperature data were collected from Chinese Geostationary Meteorological Satellite FY 2E. They were processed by using power spectrum transform method firstly. And then, a thermal infrared anomaly index based on time smoothing over particular period was proposed to calculate the degree of the anomaly in this paper. The thermal infrared anomalies extracted by the two methods were compared and analyzed. The results show that both of these methods can find the thermal infrared anomalies with a similar development trend. However, the thermal anomaly found by each method began at different times and lasted for different periods. By considering both results of the two methods, a period lasted over 10 days with high brightness temperature can be found 30 days before the Hutubi Ms6.2 earthquake. In addition, it exists another high brightness temperature period several days before Hutubi Ms6.2 earthquake. It is gradually expanded over time and tended to peak when the earthquake occurred. At last, the anomaly shrank after the earthquake until completely disappeared .