Martin R., Chevrot S., Komatitsch D., Seoane L., Spangenberg H., Wang Y., Dufrechou G., Bonvalot Sylvain, Bruinsma S. (2017). A high-order 3-D spectral-element method for the forward modelling and inversion of gravimetric data-Application to the western Pyrenees. Geophysical Journal International, 209 (1), p. 406-424. ISSN 0956-540X.
Titre du document
A high-order 3-D spectral-element method for the forward modelling and inversion of gravimetric data-Application to the western Pyrenees
Martin R., Chevrot S., Komatitsch D., Seoane L., Spangenberg H., Wang Y., Dufrechou G., Bonvalot Sylvain, Bruinsma S.
Source
Geophysical Journal International, 2017,
209 (1), p. 406-424 ISSN 0956-540X
We image the internal density structure of the Pyrenees by inverting gravity data using an a priori density model derived by scaling a V-p model obtained by full waveform inversion of teleseismic P-waves. Gravity anomalies are computed via a 3-D high-order finite-element integration in the same high-order spectral-element grid as the one used to solve the wave equation and thus to obtain the velocity model. The curvature of the Earth and surface topography are taken into account in order to obtain a density model as accurate as possible. The method is validated through comparisons with exact semi-analytical solutions. We show that the spectral-element method drastically accelerates the computations when compared to other more classical methods. Different scaling relations between compressional velocity and density are tested, and the Nafe-Drake relation is the one that leads to the best agreement between computed and observed gravity anomalies. Gravity data inversion is then performed and the results allow us to put more constraints on the density structure of the shallow crust and on the deep architecture of the mountain range.
Plan de classement
Sciences fondamentales / Techniques d'analyse et de recherche [020]
;
Géophysique interne [066]
