A global shear velocity model of the upper mantle from fundamental and higher Rayleigh mode measurements - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Journal of Geophysical Research : Solid Earth Année : 2012

A global shear velocity model of the upper mantle from fundamental and higher Rayleigh mode measurements

Résumé

We present DR2012, a global SV-wave tomographic model of the upper mantle. We use an extension of the automated waveform inversion approach of Debayle (1999) which improves our mapping of the transition zone with extraction of fundamental and higher-mode information. The new approach is fully automated and has been successfully used to match approximately 375,000 Rayleigh waveforms. For each seismogram, we obtain a path average shear velocity and quality factor model, and a set of fundamental and higher-mode dispersion and attenuation curves. We incorporate the resulting set of path average shear velocity models into a tomographic inversion. In the uppermost 200 km of the mantle, SV wave heterogeneities correlate with surface tectonics. The high velocity signature of cratons is slightly shallower (approximate to 200 km) than in other seismic models. Thicker continental roots are not required by our data, but can be produced by imposing a priori a smoother model in the vertical direction. Regions deeper than 200 km show no velocity contrasts larger than +/- 1\% at large scale, except for high velocity slabs within the transition zone. Comparisons with other seismic models show that current surface wave datasets allow to build consistent models up to degrees 40 in the upper 200 km of the mantle. The agreement is poorer in the transition zone and confined to low harmonic degrees (<= 10).
Fichier principal
Vignette du fichier
jgrb17327.pdf (3.29 Mo) Télécharger le fichier
Origine : Fichiers éditeurs autorisés sur une archive ouverte
Loading...

Dates et versions

hal-00772407 , version 1 (10-04-2013)

Identifiants

Citer

Eric Debayle, Yanick Ricard. A global shear velocity model of the upper mantle from fundamental and higher Rayleigh mode measurements. Journal of Geophysical Research : Solid Earth, 2012, 117, pp.B10308. ⟨10.1029/2012JB009288⟩. ⟨hal-00772407⟩
133 Consultations
225 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More