利用小波包分析进行地震相关热红外辐射异常信息检测

Earthquake-related thermal-infrared abnormity detection with wavelet packet decomposition

研究表明很多地震前后存在明显的热红外辐射异常.影响地物热红外辐射信息的因素很多,而地震相关的热红外辐射异常是强干扰背景下的弱信息,难以简单地将其提取出来.本文将地震相关的热红外辐射异常作为一种事件性的信号分析,通过小波包分析将热红外辐射信息的时间序列分解成不同频带的信号,通过分析各频带信号能量的变化规律进行事件性信号检测.2005年11月26日九江地震、2006年4月21日堪察加地震和1998年8月27日伽师地震的研究结果表明,小波包分析能有效检测这种事件性信号,同时显示这种事件性信号与地震活动之间关系的机理和时空演化特征是进一步研究的重点.

Former researches show that thermal-infrared radiation abnormity can be observed before or after earthquakes. The thermal-infrared radiation of earth surface is composed of many elements, and the earthquake-related information is a weak signal in the strong background noise. So it is very difficult to extract it with a simple method mentioned by some researchers. We deal with this kind of earthquake-related information as a paroxysmal signal. The wavelet packet decomposition was used to analyze the time series of thermal-infrared radiation, the complicated elements were decomposed to different frequency band signals, According to the variation of the energy of these signals, the paroxysmal signal were detected. Results from Jiujiang earthquake on 26th, Nov. 2005, Kamchatka Peninsula earthquake on 21st, Apr. 2006, and Jiashi earthquake on 27th, Aug. 1998, show that it is an effective approach to detect earthquake-related paroxysmal signal, but it is a key problem to understand the mechanism and temporal-spatial relationship between thermal-infrared abnormity signal and earthquake event.