Ground EMI: designing the future trends in shallow depth surveying
Abstract
In theory, electromagnetic induction phenomena are driven by three fundamental properties (conductivity, susceptibility, permittivity). Since the 1930's, the developments of EMI prospecting were based on assumptions (Low frequency VS High frequency, low/high induction number). The design of the devices was focused on specific aims (diffusive/propagative, mapping/sounding) and, in the last thirty years the progressive transition from analog to numeric electronics completely enhanced the potency of measurements (multi-channeling, automatic positioning) a) as it did in model computation. In the field of metric sized devices for lower depths of investigation, the measurements have been first restricted to electrical conductivity. However, the measurement of the magnetic susceptibility proved to be possible thanks to in phase and quadrature separation, and the last developed commercially available multi-frequency and/or multi-receivers devices permit, thanks to accurate calibration, the measurements of the three properties with various geometries or frequencies simultaneously. The aims of this study is to present theoretical results in order to give hints for designing a device which can be optimal to evaluate the three properties and their frequency dependence.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2017
- Bibcode:
- 2017AGUFMGP33A0944T
- Keywords:
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- 0925 Magnetic and electrical methods;
- EXPLORATION GEOPHYSICS;
- 1515 Geomagnetic induction;
- GEOMAGNETISM AND PALEOMAGNETISM;
- 3006 Marine electromagnetics;
- MARINE GEOLOGY AND GEOPHYSICS;
- 5109 Magnetic and electrical properties;
- PHYSICAL PROPERTIES OF ROCKS