High resolution spatial and temporal laboratory seismic datasets by Laser Doppler Vibrometry
Résumé
We propose to perform sub-metric scale seismic measurements with innovative experimental tools in a laboratory environment which reproduces large-scale field explorations in well conditioned and controlled environment. The purpose is to develop high resolution seismic methods on various natural samples, that can be transferred later to large-scale field conditions.Seismic waves are produced in our experiments by a P-wave piezoelectric transducer stuck to the sample surface. Nanometer mechanical displacements induced by the transducer are measured by LDV all around the sample. The measurement techniques and data acquisition chain are tested in an aluminum cuboid of 280 mm side length. High-resolution (ds ∼1 mm, dt ∼ 10 ns) unidimensional mappings of surface displacements on various faces of the cuboid are performed; furthermore, multidimensional datasets are obtained on both cuboid and cylinder samples by full-field 3D Scanning Vibrometers thanks to the collaboration with Polytec GmbH. Parallel 2D/3D numerical simulations using IPDG discretization method are done to match the experimental data.The excellent agreement between experiments and simulations demonstrates that the full wave field is accurately recorded by LDV, as well as validating the numerical scheme and models. Particularly, analyses on the experimental and simulated multidimensional data will enable us to quantify the AVA influences on the measurements along interfaces.
Domaines
Géophysique [physics.geo-ph]Origine | Fichiers produits par l'(les) auteur(s) |
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