Lateral heterogeneity of Europe's upper mantle as inferred from modelling of broad-band body waves

The upper mantle velocity structure beneath Europe is investigated by body-wave modelling of broad-band seismograms from earthquakes in the eastern Mediterranean recorded by stations in north-west Europe. The gross features of the P- and S-wave velocity distribution as inferred from the data show a high velocity lid, a low velocity zone, and two discontinuities at depths of approximately 420 and 650 km. The seismograms also present evidence for lateral heterogeneity of at least a few per cent (2.5 per cent for P, 4 per cent for S) to a depth of approximately 400 km. Many of the inferred velocity variations can be related to the tectonic setting of the region between source and receiver. Broad-band seismograms are essential for such detailed study of upper mantle structure using body-wave modelling.