江苏地区地磁准基本场的研究

江苏地区自1978年起,已陆续建成地磁绝对观测台近廿个,各台点距一般五十公里左右,其空间分布也较均匀,台站主要任务为每日定时观测地磁场总强度与垂直分量。用地磁总强度F、垂直分量Z及水平分量H(由F、Z求出)的准静日年均值,按Harder等提出的曲面样条函数计算地磁各量于各年度的空间等值线分布及沿东西方向和南北方向的等梯度线分布,结果表明江苏大部份地区地磁场的空间分布符合正常场的特征。这对进行长期连续观测和地震预报探索是有利的。本文尝试用消去正常场的办法来突出局部磁异常,所得到的南京地区局部异常区和以往的地磁及地质研究工作的结论比较吻合。无疑,在地震预报研究及其它磁测资料通化等工作中,都应注意到局部磁异常区的存在。

AN ANALYSIS OF THE MAIN GEOMAGNETIC FIELD OF JIANGSU PROVINCE

Since 1978, about 20 geomagnetic stations which measure the totalintensity and its vertical vector of geomagnetic field by proton magneto-meters, have been set up in Jiangsu province. The stations are regularlydistributed with an approximate distance of 50 km. In the research of main geomagnetic field we fit the annual averageof the daily measured observational values without magnetic storm byusing the mathematical model of Harder and Desmaris. The charts ofmain geomagnetic equivalent line can not only represent the normal fieldin Jiangsu province, but also demonstrate the regional magnetic anomaliesclearly. The main geomagnetic field distribution in Jiangsu province obtainedin this paper are fairly consistent with that from the reference field ofChina for the 1970 S.