陕西地区地磁湾扰异常

本文从频率域分析了陕西近年来记到的约十个地磁湾扰和磁扰。结果表明,渭河南北的垂直分量位相相反,水平分量也存在异常,源场极化方向和异常幅度有一走关系,同相和异相感应矢量指向渭河方向,这些都说明感应电流从渭河地堑下集中流过。据此推测在地壳下部或地幔上部存在一高导体。结合邻区地磁湾扰和其它短周期异常认为,这个高导体可向东西延伸上千公里长。

ON THE ANOMALIES OF GEOMAGNETIC BAYS IN SHAANXI REGION

In this paper,we have analysed,in the frequency domain,ten bay disturbances and magnetic disturbances in Shaanxi in recent years.The results show that the phases of the vertical components on the south and north sides of the Wei River are opposite.Horizontal components also have anomalous changes.There are some relationships between polarisation direction and anomalous amplitude Both inphase and out-of-phase induction vectors are directing to the Wei River strike These indicate the presence of a concentrated internal electrical current flowing beneath the Wei River graben.It is postulated that a high conductive body exists in the lower crust or upper mantle.From the above results,anomalies of magnetic bay disturbances a'nd other short period events in the neighbouring region,we have inferred that the high conductive body may extend more than a thousand kilometres to along the east and west direction.