Thickness and Vp/Vs Ratio Variation in the Iberian Crust
Local estimates of crustal thickness and VP/VS ratio across the Iberian Peninsula have been obtained from the stacking of teleseismic P-to-S converted waves and multiply reverberated waves at the crust–mantle boundary. The stacking procedure requires an a priori knowledge of the bulk P-wave velocity of the crust, which has been obtained by averaging independent seismic profiling velocity models. The thicknesses and VP/VS ratios reported in this work fit well within the tectonic framework operating in the region, and clearly image features such as the crustal roots at the Pyrenees and Catalan Coastal Ranges, and the stretched crust in the València Trough. Our analysis also confirms the presence of an uppermost mantle velocity contrast east of the Palomares Fault. In the Iberian Massif, our results indicate that the thickness of the crust (30 ± 2 km) is lower than expected for a continental crust of Palaeozoic age. The possibility of removal of mafic lower crust could not be assessed from the corresponding VP/VS average in this unit (1.74 ± 0.05) . Our estimates agree with seismic profiling estimates and extend those results with local estimates for thickness and VP/VS ratio at 11 sites in Iberia.
Document Type: Research Article
Affiliations: 1: Department of Geosciences, Penn State University, University Park, Pennsylvania, USA., Email: [email protected] 2: Observatorio Simológico del Sur-Occidente, Universidad del Valle, Cali, Valle, Colombia., Email: [email protected]
Publication date: 2004-01-01