High resolution quantitative seismic imaging of a strike-slip fault with small vertical o set in clay-rocks from underground galleries. Experimental Platform of Tournemire, France.
type: Dataset
description: Imaging tectonic faults with small vertical offsets in argilittes (clay-rock) using geophysical methods is challenging. In the context of deep radioactive waste disposals, the presence of such faults has to be assessed since they can modify the rock confining properties. In the Tournemire Experimental Platform (TEP, France), fault zones with small vertical offsets and complex shape have been identified from underground works. However, 3D high-resolution surface seismic methods have shown limitations in this context that led us to consider the detection and characterization of the faults directly from underground works. We investigate here the potential of seismic full waveform inversion (FWI) applied in a transmission configuration to image the clay-rock medium in a horizontal plane between galleries, and compare it with first-arrival traveltime tomography (FATT). Our objective is to characterize seismic velocities of a block of argilittes crossed by a subvertical fault zone with a small vertical offset. The specific measurement configuration allows us to neglect the influence of the galleries on the wave propagation and to simplify the problem by considering a 2D isotropic horizontal imaging domain. Our FWI scheme relies on a robust adaptation of early-arrival waveform tomography. The results obtained with FATT and FWI are in accordance and both correlate with the geological observations from the gallery walls and boreholes. We show that even though various simplifications are done in the inversion scheme and only a part of the data is used, FWI allows to get higher resolution images than FATT, and is especially less sensitive to the incomplete illumination as it uses also diffracted energy. The results provided in this study highlight the complexity of the fault zone, showing a complex interaction of the main fault system with a secondary system composed of decimetric fractures associated with the presence of water.
issued: 2026-05-08T06:32:46.214457
language: en
modified: 2026-05-08T06:32:46.214462
contact point: Organization
  fn: CCSD
keyword: argilites
keyword: full-waveform-inversion
keyword: infoeu-reposemanticspreprint
keyword: physphysphys-geo-phphysics-physicsphysics-physicsgeophysics-physicsgeo-ph
keyword: preprints-working-papers-
keyword: radioactive-waste-repositories
keyword: sdemcgenvironmental-sciencesglobal-changes
keyword: sdustugpsciences-of-the-universe-physicsearth-sciencesgeophysics-physicsgeo-ph
keyword: seismic-imaging
keyword: strike-slip-fault-with-small-vertical-offset
landing page: https://hal.science/hal-00903789

High resolution quantitative seismic imaging of a strike-slip fault with small vertical o set in clay-rocks from underground galleries. Experimental Platform of Tournemire, France.
type: Distribution
format: HTML
issued: 2026-05-08T06:32:46.230085
modified: 2026-05-08T06:32:46.202673
access URL: https://hal.science/hal-00903789

test_moissonnage_selune
type: Agent