The European Upper Mantle as Seen by Surface Waves

Abstract

We derive a global, three-dimensional tomographic model of horizontally and vertically polarized shear velocities in the upper mantle. The model is based on a recently updated global database of Love-and Rayleigh-wave fundamental-mode phase-anomaly observations, with a good global coverage and a particularly dense coverage over Europe and the Mediterranean basin (broadband stations from the Swiss and German seismic networks). The model parameterization is accordingly finer within this region than over the rest of the globe. The large-scale, global structure of our model is very well correlated with that of earlier shear-velocity tomography models, based both on body-and surface-wave observations. At the regional scale, within the region of interest, correlation is complicated by the different resolution limits associated to different databases (surface waves, compressional waves, shear waves), and, accordingly, to different models; while a certain agreement appears to exist for what concerns the grand tectonic features in the area, heterogeneities of smaller scale are less robustly determined. Our new model is only one step towards the identification of a consensus model of European/Mediterranean uppermantle structure: on the basis of the findings discussed here, we expect that important improvements will soon result from the combination, in new tomographic inversions, of fundamental-mode phase-anomaly data like ours with observations of surface-wave overtones, of body-wave travel times, of ambient ''noise'', and by accounting for an a-priori model of crustal structure more highly resolved than the one employed here.

A shear wave velocity model of the European upper mantle from automated inversion of seismic shear and surface waveforms

“…The upper mantle in the area has been the target of a number of tomographic surface wave and waveform studies (e.g. Boschi et al 2004;Marone et al 2004a;Panza et al 2007;Peter et al 2008;Schmid et al 2008;Boschi et al 2009;Chang et al 2010), with probably the highest resolution to date in the models by Boschi et al (2009) andChang et al (2010). Our models confirm the main features of this model and show a comparable or even higher resolution.…”

“…Woodhouse & Dziewonski 1984;Zhang & Tanimoto 1993). These findings were confirmed repeatedly by later, large-scale surface wave studies Mégnin & Romanowicz 2000;Ritzwoller et al 2002;Ritsema et al 2004;Levshin et al 2005 Boschi et al 2009;Lekić & Romanowicz 2011a,b;Schäfer et al 2011). The EEC has also been imaged by global body wave studies as well (e.g.…”

Plio-Quaternary uplift of the Iberian Chain (central–eastern Spain) from landscape evolution experiments and river profile modeling

“…The large-scale deformation and relatively low uplift rates producing the best fitting topography suggest that the relief generation of the Iberian Chain is probably due to mantle flow. Various studies indicate a slow velocity anomaly of seismic waves beneath central-eastern Iberia (Wortel and Spakman, 2000;Piromallo and Morelli, 2003;Li et al, 2008;Schmid et al, 2008;Boschi et al, 2009Boschi et al, , 2010Faccenna et al, 2010) A dynamic topography model predicted that this anomaly could have produced a positive topography (uplift) of~500 m (Boschi et al, 2010;Faccenna et al, 2014).…”

Anisotropic tomography of the European lithospheric structure from surface wave studies

“…Other seismologists [Boschi et al, 2009;Schaefer et al, 2011] have undertaken to parameterize the model grid in an adaptive way which takes into account the changing lateral resolution of the data. These changes are mainly dictated by unevenly distributed data coverage.…”