自然正交函数在华北地震能量场分析中的应用

Application of Natural Orthogonal Function on Analyzing Earthquake Energy Field in Northern China

运用随机函数理论,将华北地区地震活动能量场看作时间和空间的随机函数,用自然正交函数展开方法,研究地震活动区内主要典型能量场的时间权重系数变化曲线,以及该典型能量场的空间等值线分布。研究发现,在研究区内,多数中强地震前,目标曲线较大幅度的升、降变化,预示了可能发生中强地震的时间段,而目标等值线分布的疏密变化,揭示了可能发生中强地震的区域。本文研究证实,地震能量随机场的自然正交函数展开方法,是一种值得探索的地震分析预测方法。

We take earthquake energy activity field in northern China areas as a random function of space and time according to random function theory. The time weight coefficients curves and its space isopleths map of major typical energy field in the seismic activity region are studied with the expanding method of the natural orthogonal function. The results show that the variation of ascending or descending of the target curve may indicate the duration when the mid-strong earth- quake occurs, while the variation of target isopleths density may reveal the area where the mid- strong earthquake occurs. The above-mentioned phenomenon will appear before most of the mid- strong earthquakes in northern China areas, and it confirms that the natural orthogonal function of the random earthquake energy field is one of the valuable methods to explore the earthquake forecast.