Accéder directement au contenu Accéder directement à la navigation
Article dans une revue

Structural study of the Ballandaz landslide (French Alps) using geophysical imagery

Abstract : This study of the Ballandaz landslide (Savoie, French Alps) was carried out as part of the ANR/PGCU-SIGMA research project. Its aim was to characterize the slope by different methods of geophysical imagery, and then use this characterization to provide a combined interpretation of the morpho-structures in order to simulate the geomechanical behavior of the sliding mass. First, electromagnetic mapping was used to identify the variations of the surface lithology and moisture from which one can more precisely locate the active zone of the slope. Then, electrical and seismic 2D imagery methods were used along several transverse and longitudinal profiles in order to produce electrical resistivity and seismic-velocity depth sections showing up the slope's structures. The H/V method was also tested locally to determine the depth to basement so as to complement the profiles: it reveals potential seismic site effects from the deeper structures. Helped by drilling and inclinometer surveys, the geophysical interpretations have revealed the various units structuring the landslide: (i) the active, very heterogeneous shallow level overlying (ii) a more rigid, less porous, and probably stable shallow bedrock, (iii) boulders, and (iv) the sound geological basement of quartzite and gypsiferous facies. The study has shown the usefulness of combining such different sounding techniques for studying complex environments like landslides; it has also revealed the limitations of each method when used for studying very heterogeneous environments.
Liste complète des métadonnées

https://hal-brgm.archives-ouvertes.fr/hal-00630565
Contributeur : Gilles Grandjean <>
Soumis le : lundi 10 octobre 2011 - 14:04:26
Dernière modification le : vendredi 25 septembre 2020 - 03:13:47

Identifiants

Collections

Citation

Gilles Grandjean, Jean-Christophe Gourry, Olivier Sanchez, Adnand Bitri, Stéphane Garambois. Structural study of the Ballandaz landslide (French Alps) using geophysical imagery. Journal of Applied Geophysics, Elsevier, 2011, 75 (3), pp.531-542. ⟨10.1016/j.jappgeo.2011.07.008⟩. ⟨hal-00630565⟩

Partager

Métriques

Consultations de la notice

460