Ambient noise tomography of Europe using data from the VEBSN and temporary arrays

Abstract

We use 1-year continuous recordings of waveform data from the Virtual European Broadband Seismic Network (VEBSN) to obtain group and phase velocity maps of Rayleigh and Love waves of Europe and the Mediterranean region. The station coverage of the VEBSN dataset is very dense for most of central and southeastern Europe, while areas of the westernmost Mediterranean and north Africa are less well covered. To compensate for this lack of coverage we incorporate data from temporary array deployments in the westernmost Europe-Mediterranean region, including northwest Africa. With this combined dataset we are able to obtain high resolution dispersion maps for periods from 8 to 40 seconds, that are sensitive to crustal structure, including sediment and crustal thickness. In particular our dispersion maps for short periods image in great detail all major sedimentary basin, with the lowest velocity anomalies corresponding to the North German basin, Po and Adriatic, East Carpathian foredeep, Panonian basin, and the Bay of Biscay. Similarly, dispersion maps for longer periods can be considered as proxies for crustal thickness. Prominent low velocities at longer periods (and therefore greater crustal thicknesses) are observed beneath the Alps, northern Apennines, the Balkans, and the Anatolian Peninsula. The level of detail of these new maps make them suitable for joint inversion with other types of data (e.g. receiver functions, gravity anomalies) and as starting models for more advanced imaging methods such as full waveform inversion.