航空大地电磁倾子响应特征及应用效果研究

Study on the Tipper Response Characteristics and Application Effects of Airborne Magnetotelluric Method

航空大地电磁法(AFMAG)是一种被动源航空电磁类探测方法,倾子是航空大地电磁数据解释的重要参数,研究航空大地电磁倾子响应特征对于航空大地电磁数据解释具有重要意义。文章介绍了航空大地电磁法的基本原理,建立了“回”型模型,分别就高阻异常体和低阻异常体两种典型模型进行正演模拟,分析其倾子响应特征。模拟结果显示,航空大地电磁倾子参数对横向电性界面反应灵敏,并在电性交界面上形成异常中心,倾子总散度可将电性交界面的极值异常转换为异常体上方的极值异常,方便实际数据解释。在实际应用中,通过航空大地电磁法发现隐伏断裂2条,并通过航空瞬变电磁和航磁进行验证说明。结果表明,航空大地电磁法对断裂具有很好的探测效果,进一步对比航空大地电磁和航空瞬变电磁与航磁探测结果,分析航空大地电磁勘探方法的优缺点,为后续航空大地电磁法应用与解释提供依据。

Airborne magnetotelluric(AFMAG)is a passive sourc airborne electromagnetic detection method,tipper is an important parameter for the interpretation of AFMAG data,the study of the response characteristics of tipper is of great significance for the interpretation of AFMAG data.This article first introduced the basic principles of AFMAG,establishes a model,carried out forward simulations on two typical models of high-resistance anomaly and low-resistance anomaly respectively,analyzed its tipper response characteristics.The simulation results showed that the tipper parameters of AFMAG are sensitive to the transverse electrical cross-section,and forms an abnormal center on the electrical interface.The total divergence of tipper can convert the anomaly center of the tipper response into the anomaly center above the models anomaly,which is convenient for data interpretation.In actual application,two concealed faults were discovered by the AFMAG exploration methods,and verified and explained by aerial transient electromagnetic and aeromagnetic survey.Studies have shown that AFMAG has a good detection effect on faults.By further comparing the results of AFMAG with aerial transient electromagnetic and aeromagnetic detection,the advantages and disadvantages of AFMAG exploration methods was analyzed which will provide a basis for the subsequent application and interpretation of aerial magnetotelluric methods.