Ambient noise tomography of the western Corinth Rift, Greece

The Corinth Rift separates Peloponnesus to the south from main-land Greece to the north. It is one of the most active extensional intra continental rifts in the world, with geodetically measured rates of extension varying from 5nbsp;mm/yr at the eastern part to 15 mm/yr at the western part. This work presents a first attempt to study the crustalnbsp;velocity structure of the western Corinth Rift using ambient noise recordings. We used 3 yrs (01/2012-12/2014)nbsp;of continuous waveform data recorded at 24 stations from the Corinth Rift Laboratory (CRL) and the Hellenicnbsp;Unified Seismological Network (HUSN). All available vertical component time-series were cross-correlated tonbsp;extract Rayleigh wave Greenrsquo;s functions. Group velocity dispersion curves between 0.5 and 7 s period were measurednbsp;for each station pair by applying frequency-time analysis and then inverted to build group velocity maps ofnbsp;the study area. At the studied periods, the northern coast of the Corinth Rift is generally imaged as a region ofnbsp;elevated seismic velocities compared to the southern coast. More specifically, low velocities are observed in areasnbsp;of Plio-Quaternary syn-rift sediments such as off-shore regions of the rift, the Mornos delta and a large part ofnbsp;the southern coast. Higher velocities are observed in pre-rift basement structures which are dominated mostly bynbsp;carbonates. The preliminary results demonstrate good agreement with the major geological features of the areanbsp;and agree relatively well with previous local earthquake tomography studies. This work will be the base for furthernbsp;investigations towards the study of the Corinthnbsp;Rift structure using long timenbsp;series of ambient noise data./p>