A palaeoseismological and geoarchaeological investigation of the Eliki fault,Gulf of Corinth,Greece

Palaeoseismological and morphotectonic analyses enable us to define a 400-m-wide actively deformed zone associated with the active Eliki normal fault, central Greece, bounded on the south by a second-order fault and on the north by a composite and prominent fault scarp. This scarp is further analysed by trenching. Based on colluvium stratigraphy, displacement of distinct horizons and deposition of sedimentary layers, three faulting events have been identified along four fault strands affecting unconsolidated sediments in the trench. The two younger events, with throws of 0.93 and 1.37 m, respectively, the third event, with a throw of 0.44 m, and the penultimate 373 BC event suggest a variable seismic history.The entire alluvial plain of the Kerynitis and Vouraikos rivers, which cross the Eliki fault, has subsided at a rate of 1.4 mm/year, resulting in the burial of the Late Hellenistic–Roman occupation horizons under 3 m of fluvial and colluvial sediments in places.Extension in the broader area is accommodated by the seismically active Eliki and Egion faults. Structural and palaeoseismological analysis of those two faults indicates that they accommodate 1.5 mm/year, or about 10% of the geodetically estimated extension of up to 13 mm/year.