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Joint inversion of ground gravity data and satellite gravity gradients between Nepal and Bhutan: New insights on structural and seismic segmentation of the Himalayan arc / Rodolphe Cattin in Physics and chemistry of the Earth (A/B/C), vol 123 (October 2021)  

Public [article]  inPhysics and chemistry of the Earth (A/B/C) > vol 123 (October 2021) . - n° 103002 Titre : Joint inversion of ground gravity data and satellite gravity gradients between Nepal and Bhutan: New insights on structural and seismic segmentation of the Himalayan arc Type de document : Article/Communication Auteurs : Rodolphe Cattin, Auteur ; Théo Berthet, Auteur ; György Hetényi, Auteur ; Anita Thea Saraswati, Auteur ; Isabelle Panet , Auteur ; Stéphane Mazzotti, Auteur ; Cécilia Cadio, Auteur ; Matthieu Ferry, Auteur Année de publication : 2021 Projets : TOPO-Extreme / Cattin, Rodolphe, TOSCA / Cattin, Rodolphe Article en page(s) : n° 103002 Note générale : bibliographie This work was supported by grants from the Agence Nationale de la Recherche ANR-18-CE01-0017 and CNES TOSCA, as well as the Swiss National Science Foundation grant PP00P2_157627 (project OROG3NY). Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] Bhoutan [Termes IGN] gradient de gravitation [Termes IGN] gravimétrie spatiale [Termes IGN] Himalaya [Termes IGN] levé gravimétrique [Termes IGN] Népal [Termes IGN] séisme Résumé : (auteur) Along-strike variation in the geometry of lithospheric structures is a key control parameter for the occurrence and propagation of major interplate earthquakes in subduction and collision zones. The lateral segmentation of the Himalayan arc is now well-established from various observations, including topography, gravity anomalies, exhumation rates, and present-day seismic activity. Good knowledge of the main geometric features of these segments and their boundaries is thus the next step to improve seismic hazard assessment in this area. Following recent studies, we focus our approach on the transition zone between Nepal and Bhutan where both M > 8 earthquakes and changes in the geometry of the Indian plate have been documented. Ground gravity data sets are combined with satellite gravity gradients provided by the GOCE mission (Gravity Field and Steady-State Ocean Circulation Explorer) in a joint inversion to assess the location and the geometry of this transition. We obtain a ca. 10 km wide transition zone located at the western border of Bhutan that is aligned with the Madhupur fault in the foreland and coincides with the Dhubri–Chungthang fault zone and the Yadong-Gulu rift in Himalaya and southern Tibet, respectively. This sharp segment boundary at depth can act as a barrier to earthquake rupture propagation. It can possibly restrict the size of large earthquakes and thus reduce the occurrence probability of M > 9 earthquakes along the Main Himalayan Thrust. Numéro de notice : A2021-500 Affiliation des auteurs : UMR IPGP-Géod+Ext (2020- ) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.pce.2021.103002 En ligne : https://doi.org/10.1016/j.pce.2021.103002 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=98261 [article]

From space to lithosphere: inversion of the GOCE gravity gradients. Supply to the Earth’s interior study / Matthieu Plasman in Geophysical journal international, vol 223 n° 1 (October 2020)  

Public [article]  inGeophysical journal international > vol 223 n° 1 (October 2020) . - pp 398 - 419 Titre : From space to lithosphere: inversion of the GOCE gravity gradients. Supply to the Earth’s interior study Type de document : Article/Communication Auteurs : Matthieu Plasman, Auteur ; Christel Tiberi, Auteur ; Cécilia Cadio, Auteur ; Anita Thea Saraswati, Auteur ; Gwendoline Pajot-Métivier , Auteur ; Michel Diament , Auteur Année de publication : 2020 Projets : 3-projet - voir note / Cattin, Rodolphe Article en page(s) : pp 398 - 419 Note générale : bibliographie TOSCA project financing (PIGGS project) Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes IGN] anomalie de pesanteur [Termes IGN] données GOCE [Termes IGN] géophysique interne [Termes IGN] gradient de gravitation [Termes IGN] gravimétrie spatiale [Termes IGN] lithosphère [Termes IGN] problème inverse Résumé : (auteur) The emergence of high resolution satellite measurements of the gravitational field (GOCE mission) offers promising perspectives for the study of the Earth’s interior. These new data call for the development of innovant analysis and interpretation methods. Here we combine a forward prism computation with a Bayesian resolution approach to invert for these gravity gradient data configuration. We apply and test our new method on satellite data configuration, that is 225 km height with a global and homogeneous geographic distribution. We first quantify the resolution of our method according to both data and parametrization characteristics. It appears that for reasonable density contrast values (0.1 g cm−3) crustal structures have to be wider than ∼28 km to be detectable in the GOCE signal. Deeper bodies are distinguishable for greater size (35 km size at 50 km depth, ∼80 km at 300 km depth). We invert the six tensor components, among which five are independent. By carefully testing each of them and their different combinations, we enlighten a trade off between the recovery of data and the sensitivity to inversion parameters. We particularly discussed this characteristic in terms of geometry of the synthetic model tested (structures orientation, 3-D geometry, etc.). In terms of RMS value, each component is always better explained if inverted solely, but the result is strongly affected by the inversion parametrization (smoothing, variances, etc.). On the contrary, the simultaneous inversion of several components displays a significant improvement for the global tensor recovery, more dependent on data than on density variance or on smoothness control. Comparing gravity and gradient inversions, we highlight the superiority of the GG data to better reproduce the structures especially in terms of vertical location. We successfully test our method on a realistic case of a complex subduction case for both gradient and gravity data. While the imaging of small crustal structures requires terrestrial gravity data set, the longest wavelength of the slab is well recovered with both data sets. The precision and homogeneous coverage of GOCE data however, counterbalance the heterogeneous and often quite non-existence coverage of terrestrial gravity data. This is particularly true in large areas which requires a coherent assemblage of heterogeneous data sets, or in high relief, vegetally covered and offshore zones. Numéro de notice : A2020-823 Affiliation des auteurs : UMR IPGP-Géod+Ext (2020- ) Autre URL associée : vers HAL Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1093/gji/ggaa318 Date de publication en ligne : 26/06/2020 En ligne : https://doi.org/10.1093/gji/ggaa318 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=97260 [article]

New constraints on the origin of the Hawaiian swell from wavelet analysis of the geoid-to-topography ratio / Cécilia Cadio in Earth and planetary science letters, vol 359–360 (15 December 2012)  

Public [article]  inEarth and planetary science letters > vol 359–360 (15 December 2012) . - pp 40 - 54 Titre : New constraints on the origin of the Hawaiian swell from wavelet analysis of the geoid-to-topography ratio Type de document : Article/Communication Auteurs : Cécilia Cadio, Auteur ; Maxim D. Ballmer, Auteur ; Isabelle Panet , Auteur ; Michel Diament , Auteur ; Neil Ribe, Auteur Année de publication : 2012 Article en page(s) : pp 40 - 54 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] anomalie de pesanteur [Termes IGN] convection [Termes IGN] géoïde local [Termes IGN] Hawaii (Etats-Unis) [Termes IGN] houle [Termes IGN] lithosphère [Termes IGN] ondelette [Termes IGN] transformation en ondelettes [Termes IGN] volcan Résumé : (Auteur) Analyzing the formation mechanism of hotspot swells enhances our understanding of intraplate volcanism and the underlying geodynamical processes. The two main hypotheses for the origin of the archetypal Hawaiian swell are thermal lithospheric thinning, and dynamic support by an ascending plume. Any successful model would have to be able to simultaneously explain the swell topography and the corresponding geoid anomaly. In simple models of isostatic compensation, the geoid-to-topography ratio (GTR) is linearly related to the depth of the compensating mass; therefore it is often considered a fundamental parameter to assess swell support mechanisms. Previous estimates for the geoid-to-topography ratio (GTR) of the Hawaiian swell however are biased towards low values by incomplete removal of the effects of volcanic loading and lithospheric flexure. In order to resolve these issues, we here apply a continuous wavelet transform, which allows resolution of lateral variations of the GTR at various spatial scales. In a series of synthetic tests, the robustness of this approach and its power to identify the origin of hotspot swells are established. With 8 m/km on the youngest part of the chain, the recovered GTR agrees well with the predictions for dynamic support, therefore ruling out thermal rejuvenation as an important mechanism. We also find that the depth of the compensating mass decays by 20 km over a distance of 500 km from Hawaii to Kauai, and identify sublithospheric erosion by small-scale convection in the ponded plume material as a viable mechanism to support this decay. Numéro de notice : A2012-740 Affiliation des auteurs : LAREG+Ext (1991-2011) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.epsl.2012.10.006 Date de publication en ligne : 05/11/2012 En ligne : https://doi.org/10.1016/j.epsl.2012.10.006 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91475 [article]

Pacific geoid anomalies revisited in light of thermochemical oscillating domes in the lower mantle / Cécilia Cadio in Earth and planetary science letters, vol 306 n° 1-2 (June 2011)  

Public [article]  inEarth and planetary science letters > vol 306 n° 1-2 (June 2011) . - pp 123 - 135 Titre : Pacific geoid anomalies revisited in light of thermochemical oscillating domes in the lower mantle Type de document : Article/Communication Auteurs : Cécilia Cadio, Auteur ; Isabelle Panet , Auteur ; Anne Davaille, Auteur ; Michel Diament , Auteur ; Laurent Métivier , Auteur ; Olivier de Viron, Auteur Année de publication : 2011 Article en page(s) : pp 123 - 135 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes IGN] anomalie de pesanteur [Termes IGN] convection [Termes IGN] données GRACE [Termes IGN] géoïde local [Termes IGN] levé gravimétrique [Termes IGN] manteau terrestre [Termes IGN] oscillation [Termes IGN] Pacifique (océan) [Termes IGN] Polynésie française [Termes IGN] volcan Résumé : (auteur) The geoid low over French Polynesia has been previously interpreted as the signature of an upper mantle upwelling associated with a low-viscosity zone located immediately below the lithosphere. We propose here an alternative explanation using new high-quality satellite gravity data and fluid mechanics constraints. We thus discuss the origin of the high concentration of hotspots in the Central Pacific, which is still debated. Satellite gravity data from the GRACE mission analyzed with wavelets allow us to better characterize the geoid low on French Polynesia and the large-scale positive geoid anomaly 600 km east of the Line Islands chain. We show that the geoid anomalies are consistent with thermochemical oscillating domes and we bring constraints on their density contrast and their upper limit depth under this hypothesis. The Central Pacific mantle would contain two thermochemical instabilities at different stages of their development: a rising dome (lighter) extending approximately from the CMB up to the transition zone beneath the South Pacific Superswell, toped by secondary plumes that generate short-lived hot spot chains, and a sinking dome (denser) in the lower mantle beneath the area located 600 km east of the Line Islands chain. Plate reconstructions further show that the latter could also have generated the Southern Line Islands 35 M.y. ago and Shatsky Rise 140 M.y. ago when it was in its ascending phase, while the South Pacific dome probably created Darwin Rise 100 M.y. ago in a same type of event. Numéro de notice : A2011-599 Affiliation des auteurs : LAREG+Ext (1991-2011) Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.epsl.2011.03.040 Date de publication en ligne : 22/04/2011 En ligne : https://doi.org/10.1016/j.epsl.2011.03.040 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91645 [article]