Quaternary tsunami events in the eastern Ionian Sea - reconstructing and modelling extreme events based on interdisciplinary geo-scientific investigations

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The Greek coast between the Ambrakian Gulf and the southern Peloponnese is exposed to the highly tsunamigenic Hellenic Trench. It is characterized by outstanding geomorphological and sedimentological evidence of multiple strong tsunami landfalls. On a (supra-)regional scale, the eastern Ionian Sea tsunami research project focuses on the reconstruction and modelling of Holocene tsunami impacts and their influence on the long-term coastal evolution. Onshore tsunami deposits such as runup and backwash deposits, dislocated mega-blocks and allochthonous sedimentary traces in coastal plain deposits are valuable instruments to reconstruct palaeotsunami events. Event deposits, partly retrieved from vibracores, will be studied by geomorphological, sedimentological, micromorphological, micropalaeontological, geochemical and palaeoenvironmental analyses. Radiocarbon and OSL-datings are first-choice methods to establish a tsunami geochronology. Geoarchaeological studies will help to check how ancient coastal settlements were affected by (palaeo-)tsunami impacts. Field and laboratory studies will result in a GIS-related tsunami field parameter database to adapt and refine computer models of tsunami landfall and long-term coastal evolution. Computer modelling approaches will be based on wave and hydraulic theories, regional digital elevation models and high-resolution remote sensing data and take into account submarine mass movements and/or vertical plate dislocations as potential triggers. The interdisciplinary project is embedded in an international research network and shows a large innovative potential, especially by the application of (i) laser scan photogrammetric methods for modelling mega-block dislocations and (ii) 36Cl surface exposure dating for assessing the age of tsunami deposits and cross-checking other dating methods.