Voogd B. de auteur aut IRD Pou Palomé S. auteur aut IRD Hirn A. auteur aut IRD Charvis Philippe auteur aut IRD Gallard J. auteur aut IRD Rousset D. auteur aut IRD Danobeitia J. auteur aut IRD Perroud H. auteur aut IRD text journalArticle eng text/pdf reformatted digital access The structure of the submerged part of La Réunion hotspot island is determined by a grid of multichannel seismic reflection profiles. The submarine part of the edifice appears as a poorly stratified wedge of material lying above a significant thickness of preexisting sediments and the oceanic basement. The dense data coverage has allowed us to derive contour maps of the top of the basement and of the base of the volcaniclastic edifice, further constrained by coincident wide-angle profiles. The resulting isobath maps reveal new, unsuspected features that could not be deduced from observation along a single seismic line since the geometry of these horizons varies significantly from one radial profile to the next. Both maps show a large degree of heterogeneity in the topography, with no axial nor cylindrical symmetry, indicating that plate flexure is not dominant. A slight depression toward the island is observed only in the southern area, ahead of the hotspot trace. The lack of angular unconformity in the volcano-sedimentary pile that covers the oceanic basement firmly establishes the lack of significant vertical movement and flexure. The base of the edifice is roughly domed, centered on the island, with several topographic highs or lows superimposed. The submarine apron appears as a composite constructional body, spreading by slumping of its flanks. Superficial lenses of laterally transported material are observed on the seismic data south of the island, not only to the east of the active Piton de la Fournaise volcano. Oceanic sediments trapped beneath the apron seem undeformed. (Résumé d'auteur) specialized VOLCANISME POINT CHAUD SISMIQUE A REFLEXION PROFIL SISMIQUE GEOLOGIE STRUCTURALE ETUDE REGIONALE REUNION 064GEOREG 104 B2 2855-2874 1999 0148-0227 https://www.documentation.ird.fr/hor/fdi:010021652 10.1029/98JB02842 0148-0227 [F B010021652] https://www.documentation.ird.fr/hor/fdi:010021652 https://horizon.documentation.ird.fr/exl-doc/pleins_textes/pleins_textes_7/b_fdi_55-56/010021652.pdf IRD - Base Horizon / Pleins textes 2000-06-07 2018-07-10 fdi:010021652 fre