Tomography of the Indian Ocean by waveform inversion
The arrival of some plumes and the birth of hotspots at the Earth surface is more likely the cause of the break up of the Pangea ~200 Ma ago, during the jurassic era. The Gondwana was formed by many continental masses like Africa, Australia, India and Antarctic. The late cretaceous was affected by a...
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ftunivparis:oai:HAL:tel-03216584v1 2024-02-11T09:58:23+01:00 Tomography of the Indian Ocean by waveform inversion Tomographie de l'Océan Indien par inversion de forme d'onde Dongmo Wamba, Mathurin Université Paris Cité Jean-Paul Montagner Barbara Romanowicz 2020-07-08 https://theses.hal.science/tel-03216584 https://theses.hal.science/tel-03216584/document https://theses.hal.science/tel-03216584/file/DONGMO_WAMBA_Mathurin_va.pdf fr fre HAL CCSD NNT: 2020UNIP7077 tel-03216584 https://theses.hal.science/tel-03216584 https://theses.hal.science/tel-03216584/document https://theses.hal.science/tel-03216584/file/DONGMO_WAMBA_Mathurin_va.pdf info:eu-repo/semantics/OpenAccess https://theses.hal.science/tel-03216584 Sciences de la Terre. Université Paris Cité, 2020. Français. ⟨NNT : 2020UNIP7077⟩ Hotspot Mantle plume Narrow conduit Source of the hotspot Point chaud Panache mantellique Conduit étroit Source du point chaud [SDU.STU]Sciences of the Universe [physics]/Earth Sciences info:eu-repo/semantics/doctoralThesis Theses 2020 ftunivparis 2024-01-17T17:21:00Z The arrival of some plumes and the birth of hotspots at the Earth surface is more likely the cause of the break up of the Pangea ~200 Ma ago, during the jurassic era. The Gondwana was formed by many continental masses like Africa, Australia, India and Antarctic. The late cretaceous was affected by a biological crisis caused by a volcanic and/or asteroid cataclysm which provoke the disappearance of 90% of life on the Earth including dinosaurs, and produced India Deccan trapps with an area of 2 millions km^2 and thickness of 2.5-3 km. This volcanic disaster was associated with the birth of la Réunion hotspot ~65 Ma years ago, from there the india plate entered into the northward migration with a velocity of about 18-20 cm/year, and the closure of the Tethys ocean in front of the indian plate started; in the meantime the raising of basaltic lava from the indian ridges formed a new ocean floor behind the indian plate: this was the birth of indian ocean. In 1953 the Canadian researcher Tuzo Wilson suggested that such an intra-plate volcano may be due to a fixed hotspot in the mantle capable to create successive volcano on the surface; later in 1971 Jason Morgan suggested that the hotspot is fed by a mantle plume rising from the core-mantle boundary due to thermal instabilies. The goal of this thesis is to investigate the actual state of the plume in the entire indian ocean, responsible of many volcanic islands such as Maldives, Maurice and Réunion. By applying waveform inversion we are able to image the earth structure down to the lower mantle; we use Rhum-Rum data and also data collected from FDSN (Federation of Digital Seismograph Networks) data center to perfom our inversion. We perform the forward modelling with the spectral element method. For this regional case we use RegSEM (regional spectral element method) to compute synthetic seismograms that were compared to real seismograms later on. We divided the waveform into several wavepackets, each wavepacket corresponds to a specific mode. We inverted for two ... Doctoral or Postdoctoral Thesis Antarc* Antarctic Université de Paris: Portail HAL Antarctic Indian Maurice ENVELOPE(-55.817,-55.817,-63.133,-63.133) |
institution |
Open Polar |
collection |
Université de Paris: Portail HAL |
op_collection_id |
ftunivparis |
language |
French |
topic |
Hotspot Mantle plume Narrow conduit Source of the hotspot Point chaud Panache mantellique Conduit étroit Source du point chaud [SDU.STU]Sciences of the Universe [physics]/Earth Sciences |
spellingShingle |
Hotspot Mantle plume Narrow conduit Source of the hotspot Point chaud Panache mantellique Conduit étroit Source du point chaud [SDU.STU]Sciences of the Universe [physics]/Earth Sciences Dongmo Wamba, Mathurin Tomography of the Indian Ocean by waveform inversion |
topic_facet |
Hotspot Mantle plume Narrow conduit Source of the hotspot Point chaud Panache mantellique Conduit étroit Source du point chaud [SDU.STU]Sciences of the Universe [physics]/Earth Sciences |
description |
The arrival of some plumes and the birth of hotspots at the Earth surface is more likely the cause of the break up of the Pangea ~200 Ma ago, during the jurassic era. The Gondwana was formed by many continental masses like Africa, Australia, India and Antarctic. The late cretaceous was affected by a biological crisis caused by a volcanic and/or asteroid cataclysm which provoke the disappearance of 90% of life on the Earth including dinosaurs, and produced India Deccan trapps with an area of 2 millions km^2 and thickness of 2.5-3 km. This volcanic disaster was associated with the birth of la Réunion hotspot ~65 Ma years ago, from there the india plate entered into the northward migration with a velocity of about 18-20 cm/year, and the closure of the Tethys ocean in front of the indian plate started; in the meantime the raising of basaltic lava from the indian ridges formed a new ocean floor behind the indian plate: this was the birth of indian ocean. In 1953 the Canadian researcher Tuzo Wilson suggested that such an intra-plate volcano may be due to a fixed hotspot in the mantle capable to create successive volcano on the surface; later in 1971 Jason Morgan suggested that the hotspot is fed by a mantle plume rising from the core-mantle boundary due to thermal instabilies. The goal of this thesis is to investigate the actual state of the plume in the entire indian ocean, responsible of many volcanic islands such as Maldives, Maurice and Réunion. By applying waveform inversion we are able to image the earth structure down to the lower mantle; we use Rhum-Rum data and also data collected from FDSN (Federation of Digital Seismograph Networks) data center to perfom our inversion. We perform the forward modelling with the spectral element method. For this regional case we use RegSEM (regional spectral element method) to compute synthetic seismograms that were compared to real seismograms later on. We divided the waveform into several wavepackets, each wavepacket corresponds to a specific mode. We inverted for two ... |
author2 |
Université Paris Cité Jean-Paul Montagner Barbara Romanowicz |
format |
Doctoral or Postdoctoral Thesis |
author |
Dongmo Wamba, Mathurin |
author_facet |
Dongmo Wamba, Mathurin |
author_sort |
Dongmo Wamba, Mathurin |
title |
Tomography of the Indian Ocean by waveform inversion |
title_short |
Tomography of the Indian Ocean by waveform inversion |
title_full |
Tomography of the Indian Ocean by waveform inversion |
title_fullStr |
Tomography of the Indian Ocean by waveform inversion |
title_full_unstemmed |
Tomography of the Indian Ocean by waveform inversion |
title_sort |
tomography of the indian ocean by waveform inversion |
publisher |
HAL CCSD |
publishDate |
2020 |
url |
https://theses.hal.science/tel-03216584 https://theses.hal.science/tel-03216584/document https://theses.hal.science/tel-03216584/file/DONGMO_WAMBA_Mathurin_va.pdf |
long_lat |
ENVELOPE(-55.817,-55.817,-63.133,-63.133) |
geographic |
Antarctic Indian Maurice |
geographic_facet |
Antarctic Indian Maurice |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_source |
https://theses.hal.science/tel-03216584 Sciences de la Terre. Université Paris Cité, 2020. Français. ⟨NNT : 2020UNIP7077⟩ |
op_relation |
NNT: 2020UNIP7077 tel-03216584 https://theses.hal.science/tel-03216584 https://theses.hal.science/tel-03216584/document https://theses.hal.science/tel-03216584/file/DONGMO_WAMBA_Mathurin_va.pdf |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1790594020910563328 |