浙江省及其邻区红外亮温异常与地震关系

选取2006—2013年的FY2风云2号气象卫星热红外亮温夜间数据,采用相对功率谱法进行全时空分析,获得优势频率和幅值。研究每一个频率点的相对功率谱随时间和空间的变化,与浙江省及其邻区17个ML5.0以上地震的三要素关系进行分析,得到如下结果:9个地震前出现热红外亮温相对功率谱异常,前三个特征周期的对应率比后三个特征周期高;在时间上,异常多出现在震前数日至数月,并且较多发生在异常达到最大值后和异常恢复后,少部分发生在异常达到最大值前;空间上,异常的表现为由弱-强-弱-消失的过程,异常形态多为从零星异常演化成团块状或与断裂带走向较为一致的条带状。异常时间、异常幅度、异常开始到地震发生的时间等特征与地震无明显关系。

Relation between Infrared Brightness Temperature Anomalies and Earthquakes in Zhejiang Province and Its Adjacent Areas

In this study, remotely sensed infrared brightness temperature data from the China Geostationary Meteorological Satellite FY-2C/E from 2006 to 2013 are full time-space analyzed to determine the dominant frequency and amplitude using the relative power spectrum method. The variation in time and space in the relative power spectrum of each frequency was analyzed and compared with the three elements of 17 earthquakes having magnitudes greater than 5.0 in Zhejiang Province and its neighboring area. The following results were obtained: the relative power spectrum anomaly of infrared brightness temperature appears before nine earthquakes. The corresponding ratio of the first three dominant frequencies is higher than that of last three ratios. The anomalies occurred several days or months before earthquakes, and most earthquakes occurred after the anomalies reached the maximum value or were recovering. A few earthquakes occurred before the anomalies reached the maximum value. The anomalies increase in strength and then disappear, in a process from sporadic to conglomerate or banded along the fault zone. Anomaly time and amplitude and the time period from the appearance of the anomaly until the earthquakes occurred have no obvious relation with the three elements of the earthquake.