地磁低点位移内源场分布特征

Distribution Characteristics of Geomagnetic Lowest Shift Phenomenon Internal Field

采用矩谐方法分离了发生在中国南北地震带南部地区的地磁低点位移异常的内外源场,分析了畸变异常期间内外源场变化幅度与其全天变化幅度的比值,发现地磁低点位移异常期间,内源场变化幅度与其全天变化幅度的比值高于外源场变化幅度与其全天变化幅度的比值,即地磁低点位移异常期间内源场变化幅度大于外源场变化幅度,表明地磁低点位移异常来自内源场。

This article uses the method of rectangular harmonic analysis(RHA)to separate the internal and external source fields of the geomagnetic low point displacement anomaly that occurred in the southern region of the north-south seismic belt in China.It analyzes the ratio of the amplitude of the internal and external source fields during the distortion anomaly period to its diurnal amplitude.It is found that during the geomagnetic low point displacement anomaly period,the ratio of the amplitude of the internal field change to its diurnal amplitude is higher than the ratio of the amplitude of the external field change to its diurnal amplitude.During the period of geomagnetic low point displacement anomaly,the amplitude of internal field change is greater than that of external field change,indicating that the geomagnetic low point displacement anomaly comes from internal field.