A comparative analysis of geophysical fields for multi-sensor applications

Geologic investigations based on the measurement of a single geophysical field usually result in an ambiguous interpretation, whereas combining measurements of multiple geophysical fields (multi-sensor approach) leads to more reliable earth system models. A fundamental problem in the multi-sensor approach is that the response of each geophysical field to the earth's subsurface is different, which may result in discordant observations. We suggest that a common approach to geophysical fields and their applications (geophysical methods) would contribute to establishing efficient multi-sensor systems. In this study, we compare the conventional geophysical methods from both theoretical and practical aspects using their common terminologies, which reveal their basic analogies and differences. In particular, we compare shallow applications of geophysical methods as the multi-sensor approach is vitally useful for such problems. We finally discuss a practical tool for side-by-side comparison of detection reliabilities of different geophysical methods. This technique can set conditional or unconditional requirements on methods depending on a particular subsurface problem. Examples of the detection reliability from gravity gradiometry, magnetometry, and ground penetrating radar (GPR) are presented.

Research highlights
► We classify geophysical methods according to analogies in their mathematical formulations.
► These analogies can practically be used in multi-sensor applications.
► We use "detection reliability" as a practical tool for side-by-side comparison of geophysical methods.