Déformation de la lithosphère océanique : Approche numérique par éléments finis, application à la plaque Indo-Australienne.
type: Dataset
description: Plate tectonics postulate that plates are rigid and that deformations focus on their boundaries, generally narrow in oceanic areas. Some oceanic plates appear to derogate to these tenets. The Indo-Australian plate, for instance, displays a high level of intraplate seismicity expressing a high level of deformation of the oceanic lithosphere. Earthquake focal mechanisms express compressional deformation in the Eastern part of the plate and extensional deformation East of the Central Indian Ridge and North of the South-East Indian Ridge. Inversion of kinematic data, assuming rigid plates, lead to the concept of composite plates comprising rigid components separated by wide and diffuse boundaries. Using the example of the Indo-australian plate, this dissertation investigates how the oceanic lithosphere behaves when submitted to horizontal stresses and the role of preexisting features such as submarine plateaus or fossil fracture zones on the deformation pattern. The first part of this work focuses on the distribution of the low magnitude seismic activity in the deformed areas using hydroacoustic records from 3 autonomous hydrophones in the Southern Indian Ocean. The objective was to identify and localize active structures in the deformed areas. Due the geometry of this temporary array, little new information could be obtained, however these data confirmed the reactivation of fossil fracture zones in the extensional areas. The discovery of seismic foreshocks preceding high magnitude earthquakes along active transforms of the East Pacific and Juan de Fuca ridges lead us to search for such precursors in our data. A foreshock is defined as an event occurring few hours before a major event within a 100 km radius around it. No such foreshocks were detected in our partial analysis of data from the Comprehensive Nuclear-Test-Ban Treaty (CTBT) hydroacoustic array. From the data of our temporary array, 13 events were identified as foreshocks few hours before major events on fract…
issued: 2026-05-24T07:57:59.882361
language: fr
modified: 2026-05-24T07:57:59.882366
contact point: Organization
  fn: CCSD
keyword: deformation
keyword: deformations
keyword: elements-finis
keyword: finite-elements
keyword: foreshock
keyword: geophysic
keyword: geophysique
keyword: hydroacoustic
keyword: hydroacoustique
keyword: infoeu-reposemanticsdoctoralthesis
keyword: modelisation
keyword: physphysphys-geo-phphysics-physicsphysics-physicsgeophysics-physicsgeo-ph
keyword: precurseurs
keyword: sdustugpsciences-of-the-universe-physicsearth-sciencesgeophysics-physicsgeo-ph
keyword: sismic
keyword: sismique
keyword: tectonic
keyword: tectonique
keyword: theses
landing page: https://theses.hal.science/tel-00680190

Déformation de la lithosphère océanique : Approche numérique par éléments finis, application à la plaque Indo-Australienne.
type: Distribution
format: HTML
issued: 2026-05-24T07:57:59.987359
modified: 2026-05-24T07:57:59.819273
access URL: https://theses.hal.science/tel-00680190

test_moissonnage_selune
type: Agent