Feng, L., & Diaz, J. (2023). A High-Resolution Shear Velocity Model of the Crust and Uppermost Mantle beneath Westernmost Mediterranean including Radial Anisotropy. Journal of Geophysical Research: Solid Earth, n/a(n/a), e2023JB026868. https://doi.org/10.1029/2023JB026868
Abstract
Using seismic data from 1186 stations deployed across the westernmost Mediterranean, we construct a high-resolution 3-D radially anisotropic model from a joint inversion of receiver functions and Rayleigh and Love wave dispersions. The Rayleigh and Love data are extracted from both ambient noise interferograms and earthquake waveforms, and a new three-station ambient noise interferometry method is used to further improve the data coverage.
The obtained crustal thickness map reproduces independently the Moho depth maps compiled from previous data, showing crustal roots beneath the Pyrenean-Cantabrian range and the Gibraltar Arc and thicker crust beneath the Variscan Iberian Massif than in the area affected by Alpine orogenesis. The Vsv crustal model outlines the Iberian Massif as a high shear wave velocity block and shows extremely low velocities in the Gulf of Cadiz and Gibraltar Arc. At mantle levels, a sharp boundary between the Aquitanean Basin and the Massif Central is imaged, with the low Vsv beneath the Massif Central probably reflecting a remaining signature of the magma. To the south of Iberia, the geometry of the Alboran slab is captured by the model, while beneath the Atlas Mountains, widespread low Vsv and positive radial anisotropy is observed, favoring the edge-driven convection (EDC) model explaining the lithospheric thinning. The most relevant contribution of this work is mapping, for the first time at this scale, the radial anisotropy anomalies at crustal level, with higher values observed in the Alpine Iberia, dominated by present-day extensional tectonics.