Three-dimensional forward modeling study of multi-source magnetic tipper

The tipper, as a crucial parameter in electromagnetic exploration methods, effectively reflects complex underground structures and anomaly outlines. For multi-frequency data and data containing harmonics, single-source and dual-source tippers fail to fully utilize the data information. To maximize the use of measured three-component magnetic field data, a multi-source tipper sounding method is proposed. Based on the calculation methods of single-source and dual-source tippers, the multi-source tipper formula is derived using the least squares method. Three-dimensional forward modelling of multi-source tippers is conducted using the frequency-domain finite difference method (FDFD), and the response characteristics of multi-source tippers are analysed. The effectiveness of tippers in observing underground anomalies is confirmed, and it is demonstrated that theTzytipper performs better than theTzxtipper in detecting anomalies. The results verify that multi-source tippers are more effective than single-source and dual-source tippers in reflecting low-resistivity/high-resistivity anomalies and can utilize the collected data more efficiently. This method can be applied to very low-frequency (VLF) airborne detection for identifying structural boundaries.