Some aspects of the radio-magnetotelluric method and instrumentation development

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Abstract

In recent decades, the demand for shallow geophysical methods and instruments has changed significantly. Today, there is only a need for methods and instruments that can provide a large amount of accurate measurement results in a short time, which are suitable for developing effective inversion procedures. Only contactless methods can meet the speed requirement. The measurement technique is significantly simplified if we can use a signal source that is of natural origin or an artificial source created for other purposes (e.g. radio transmitters). The radio-magnetotelluric method (RMT), which can be considered an extended variation of the popular very low frequency (VLF) method in terms of frequency range, is exactly such a method. Another advantage is that the created field can be considered a plane wave, thus simplifying the data processing and interpretation procedures. This study presents a brief history of the development of VLF-RMT methods, the evolution of instruments, the development of processing methods, the characteristics of modern inversion methods, and then summarizes the aspects of designing a modern RMT instrument.