地球物理问题中电磁感应的实验室模拟模型研究

在地球物理问题中,有两种方法通常用于解释地磁和地电异常,这就是数字模型技术和实验室模拟模型法。实验室模拟模型对于分析不易求得数学解的问题非常有用,并且已经广泛用于研究复杂的地球物理问题。本文评述了国外特别是加拿大开展模拟模型研究的情况;描述了平面波、线电流、磁偶极等各种类型的场源模型;给出了该法在研究海岸效应、岛陆通道电流、海浪电磁效应和各向异性导体等方面的应用。模拟模型测量和数字计算的比较结果显示了非常好的一致性,这就进一步证实了模拟模型法对于研究复杂二维和三维感应问题的可靠性。该项研究工作对于了解天然电磁场源的性质、进行地球物理勘探以及研究地球地壳和地幔的电性结构都十分有益。

LABORATORY ANALOGUE MODEL STUDIES OF ELECTROMAGNETIC INDUCTION IN GEOPHYSICAL PROBLEMS

In geophysical problems,two methods commonly used in the interp-retation of geomagnetic and geoelctric field anomalies are numerical modelling techniques and laloratory analogue model methods.Laboratory analogue models are found to be very useful in anatysing problems which do not yield really mathematical solution,and have been extensi-vely used in studying complicated geophysical problems.The present work reviews the development of analogue model method in the world,especialty in Canada;describes various kinds of source field models,such as plane wave model,line current model,and mag-netic dipole model;and shows the applications to studying the coast effects,island-continent ocean channels,electromagnetic effects inducec by ocean waves,aond anisotropic conductors.The results of comparison of analogue model measurements and numerical calculations indicate very good agreement,arid confirm the validity of the analogue method for studying complex two-and three-dimensional induction problems.such research work goes a long way in understanding the behaviour of natural electromagnetic field,carrying out geophysical prospecting,and investigating the electrical structures of the Earth''s crust and mantle.