中国大陆及邻近海域的中强地震热红外异常研究

应用中国静止气象卫星FY-2C/2E遥感亮温资料,通过小波变换和计算相对功率谱,分析提取了中国大陆及邻近海域14次中强地震的热红外异常特征。其特征为:(1)异常具有明显的特征周期。大陆地震的周期主要为13天和64天,海域地震的周期都在32天以下。震中位置相近的地震具有相同的特征周期;(2)异常的最大幅度明显且易于识别。幅度都在8倍以上,最高甚至达到20倍;(3)地震多发生在异常区域的内部及其边缘,异常出现与消失的过渡区域是可能的震中位置;(4)干旱地区大陆地震的特征周期较长,潮湿地区的较短;(5)最大异常出现时间与地震发生时间的关系、异常峰值与震级的关系尚不明确;(6)对比大陆地震与海域地震,二者在异常幅度、异常出现时间与地震时间的关系、异常幅度与震级的关系等方面存在相似性,在特征周期和异常范围方面的表现有所不同。

Study of Thermal Infrared Anomalies of Moderately Strong Earthquakes in Mainland and Adjacent Sea of China

The thermal infrared anomaly characteristics of 14 moderately strong earthquakes happened in the mainland and adjacent sea of China are extracted and analyzed by wavelet transform and relative power spectrum calculation according to the remote sensing brightness temperature data from geostationary meteorological satellites FY-2C/2E of China. The anomaly characteristics include: (1) Anomalies have obvious characteristic periods. The periods for mainland earthquakes are 13 days and 64 days and those for sea earthquakes are less than 32 days. The earthquakes with similar epicentral positions have the same characteristic periods; (2) Maximum anomaly amplitude is obvious and easy to be identified. Most of the amplitude is more than 8 times, and even up to 20 times; (3) Earthquakes are located in the interior and edges of anomaly regions. The transition areas in which anomalies appear and disappear are possible epicenters; (4) Earthquakes happened in arid areas have longer characteristic periods and those happened in wet areas have shorter characteristic periods; (5) The relationship between maximum anomaly occurring time and earthquake happening time and the relationship between anomaly peak and amplitude are not clear yet; (6) By comparison, mainland earthquakes and sea earthquakes have the similarity in above relationships, but their characteristic periods and anomaly areas are different.