Influence of grain size, shape and compaction on georadar waves: examples of aeolian dunesReport as inadecuate




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1 Institut de physique du globe Strasbourg IPGS - Institut de physique du globe de Strasbourg

Abstract : Many ground penetrating radar GPR profiles acquired in dry aeolian environment have shown good reflectivity inside present-day dunes. We show that the origin of this reflectivity is related to changes in grain size distribution, packing and-or grain shape in a sandy material. We integrate these three parameters into analytical models for bulk permittivity in order to predict the reflections and the velocity of GPR waves. We consider two GPR cross-sections acquired over aeolian dunes in the Chadian desert. The 2D migration of GPR data suggests that dunes contain different kinds of bounding surfaces. We discuss and model three kinds of reflections using reasonable geological hypothesis about aeolian sedimentation processes. The propagation and the reflection of radar waves are calculated using the 1D wavelet modelling method in spectral domain. The results of the forward modelling are in good accordance with real observed data.

Keywords : Numerical solutions Electrical properties Electromagnetic theory Ground penetrating radar





Author: Julien Guillemoteau - Maksim Bano - Jean-Rémi Dujardin -

Source: https://hal.archives-ouvertes.fr/



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