HR: 11:40h
AN: G22A-06    [Abstracts]
TI: Wavelet Modelling and Analysis of new Space Gravity Data in Combination With Surface Data: Application to the South Central Pacific Volcanism
AU: * Panet, I
EM: panet@ipgp.jussieu.fr
AF: Institut de Physique du Globe de Paris, case 89, 4, place Jussieu, Paris, 75252 France, Metropolitan
AU: * Panet, I
EM: panet@ipgp.jussieu.fr
AF: Laboratoire de Recherche en Géodésie, Institut Géographique National, 6/8, avenue Blaise Pascal - ENSG - Champs sur Marne, Marne la Vallée, 77455 France, Metropolitan
AU: Diament, M
EM: diament@ipgp.jussieu.fr
AF: Institut de Physique du Globe de Paris, case 89, 4, place Jussieu, Paris, 75252 France, Metropolitan
AU: Holschneider, M
EM: hols@math.uni-potsdam.de
AF: Department of Applied Mathematics, University of Potsdam, Am Neuen Palais, 10, Potsdam, 14469 Germany
AU: Jamet, O
EM: jamet@ensg.ign.fr
AF: Laboratoire de Recherche en Géodésie, Institut Géographique National, 6/8, avenue Blaise Pascal - ENSG - Champs sur Marne, Marne la Vallée, 77455 France, Metropolitan
AU: Chambodut, A
EM: chambodu@math.uni-potsdam.de
AF: Department of Applied Mathematics, University of Potsdam, Am Neuen Palais, 10, Potsdam, 14469 Germany
AB: Present and forthcoming satellite gravity missions provide us with new and unique datasets in order to model the Earth's gravity field and its temporal variations at large and medium wavelengths. These new models will bring significant advances in our understanding of the Earth's structure and dynamics, from the deepest processes to the superficial ones. However, the need is expressed to derive local gravity models of increased resolution in areas of interest. Moreover, solid Earth's processes occur and interact in a wide range of spatial scales. Performant methods are needed to analyze the derived models.
For that aim, we use a wavelet-based representation of the gravity field in spherical geometry. Wavelets indeed offer a good flexibility. Thanks to their good localization in space and frequency, they can handle a local, high resolution zoom among a global, low-resolution model, leading to adaptative solutions. We thus compute a regional gravity model of increased resolution over South Central Pacific, a region showing numerous anomalous features, the origin of which remains a matter of debate. Our new gravity model is based on GGM02S gravity model, KMS 2002 satellite-derived gravity grid and ship data. We also compute a magnetic model based on CHAMP magnetic data.
We analyze our new gravity model at varying spatial scales. We show that a continuous spherical wavelet analysis of the combined gravity model can easily be derived and related to the internal distribution of densities. It allows to underline geophysical features in a wide range of spatial scales. To establish whether they are of superficial or deep origin, we finally evaluate the contribution of the bathymetric relief in spherical geometry. This allows us to highlight new structures in the gravity field. We interpret and discuss our results in terms of emplacement mechanism for the intraplate volcanism. We show that different processes have to be invoked to explain what was previously assumed to be classical hot-spot lines.
DE: 1214 Geopotential theory and determination (0903)
DE: 1219 Gravity anomalies and Earth structure (0920, 7205, 7240)
DE: 3037 Oceanic hotspots and intraplate volcanism
DE: 3280 Wavelet transform (3255, 4455)
SC: Geodesy [G]
MN: Fall Meeting 2005