Abstract
The Ionian Sea hosts the last remnant of Tethyan oceanic lithosphere subducting beneath Calabria, where active deformation generates significant seismicity, including earthquakes exceeding magnitude 7. The main tectonic structures - the Ionian Fault system, the Alfeo–Etna Fault system, and the Malta Escarpment - accommodate African–Eurasian plate convergence and margin segmentation under a transtensional regime. Here we present two new datasets of 3D earthquake locations and focal mechanism solutions to constrain fault kinematics in the Ionian region. The first dataset includes 5,240 relocated small-magnitude earthquakes (0.7 ≤ ML ≤ 4.7) recorded between 1990 and 2019. Hypocentral locations were determined integrating travel-times data from land-based and seafloor seismic stations to improve spatial resolution. The second dataset comprises 421 new focal mechanism solutions (1.5 ≤ ML ≤ 4.7) for earthquakes occurring in the Ionian Sea and adjacent areas.
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Data availability
Original earthquake parameters (locations and travel-times) are available on the INGV institutional websites (https://bsi.ingv.it/it/archivio-dati; http://terremoti.ingv.it/; https://www.ct.ingv.it/index.php/monitoraggio-e-sorveglianza/banche-dati-terremoti/terremoti).
All data are shared under the Creative Commons Attribution 4.0 International use license (without restrictions) and available at the links: https://oedatarep.ct.ingv.it/records/8vxp0-wtp69 (URL), https://doi.org/10.13127/wiseloc/1990-2019; and https://oedatarep.ct.ingv.it/records/jn7kb-xf626 (URL), https://doi.org/10.13127/wisefm/1990-2019.
Code availability
All codes used in this study are described in detail in the Methods section. Surfer was used to plot events and focal mechanisms. Corel Draw 2020 was used for creating all the figures.
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Acknowledgements
We thank the Editor Board member Francesco Grigoli and the two reviewers (Gian Maria Bocchini and the anonymous reviewer) for their insightful comments and suggestions.
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The first two authors, T.S. and G.B., contributed equally to the present paper to all stages of this research. T.S., G.B. and A.M. prepared the two seismological databases. L.G. and A.P. contributed to the tectonic validation of fault traces and to the general discussion. All authors have read and agreed to this version of the manuscript.
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Sgroi, T., Barberi, G., Marchetti, A. et al. The new earthquake locations and focal mechanisms catalogues for the western Ionian Sea, Italy. Sci Data (2026). https://doi.org/10.1038/s41597-026-06979-w
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DOI: https://doi.org/10.1038/s41597-026-06979-w
