Preliminary Surface-wave Velocity Imaging from Ambient Noise in Northwestern Peloponnese, Greece

Abstract Northwestern Peloponnese, in western Greece, lies within the complex geodynamic setting of the Eastern Mediterranean. The large-scale tectonics of the region are controlled by the convergence of the African and Eurasian plates along the Hellenic Subduction System (HSS), the westward extrusion of the Anatolian block, and the Eurasian-Apulian plate collision. We present preliminary results from an ambient noise tomography analysis aimed at imaging the upper crust beneath Northwestern Peloponnese. The analysis is based on two years of continuous seismic recordings (December 2023 - December 2025) from permanent stations of the Hellenic Unified Seismological Network integrated with data from several temporary deployments (e.g. AdriaArray). Daily vertical-component recordings are pre-processed and cross- correlated to retrieve surface-wave empirical Green’s functions. Rayleigh-wave group velocity dispersion curves are extracted from the cross-correlations and inverted to obtain 2D surface-wave velocity maps. The resulting velocity maps provide a first-order image of lateral velocity variations across Northwestern Peloponnese.