CAJ | 학술논문

大回线源作为一种快速有效的瞬变电磁观测方式,它的优点是铺设一次线框,在框内和框外都可以测量,空间采样率高、工作效率高和解释精度高,特别适合高密度、大深度的面积测量。目前针对矩形源计算有两种方式,①通过面积等效法用圆形发射源代替矩形发射源；②利用水平偶极子沿矩形回线做数值积分。这里计算了两种发射装置内二次场值,研究两种发射源内二次场的分布特征,证明对于中心回线装置、大定源装置,在晚期使用面积等效方法用圆型线框代替矩型线框计算视电阻率是有效的,在早期计算会引入较大误差,需要校正。
대회선원작위일충쾌속유효적순변전자관측방식,타적우점시포설일차선광,재광내화광외도가이측량,공간채양솔고、공작효솔고화해석정도고,특별괄합고밀도、대심도적면적측량。목전침대구형원계산유량충방식,①통과면적등효법용원형발사원대체구형발사원；②이용수평우겁자연구형회선주수치적분。저리계산료량충발사장치내이차장치,연구량충발사원내이차장적분포특정,증명대우중심회선장치、대정원장치,재만기사용면적등효방법용원형선광대체구형선광계산시전조솔시유효적,재조기계산회인입교대오차,수요교정。
Large-loop source as a quick and efficient observation way of transient electromagnetic,it has the advantage of laying a wireframe,outside and inside the box being measured,high spatial sampling rate,high work efficiency and interpreta-tion accuracy,especially suitable for the area survey of high density and big depth.At the moment,there are two calculation ways for rectangular source.The first is using circular transmitter source instead of rectangular transmitter source;The second is using a horizontal dipole along the rectangular loop for numerical integration.This paper calculate the secondary field value within two transmitters loop,study the distribution characteristics of secondary field of two kinds source in the loop,proved that for the central loop device and large fixed source device.The method that using a circular transmitter wireframe instead of rectangular transmitter wireframe to calculate the apparent resistivity in the later period is effective,calculation the early appar-ent resistivity will introduce greater error and needs correction.