Geographical overview of the study sites. (A) Map of Greece showing the Hellenic trench, the plate boundaries and the major fault systems modified after Panagiotaras et al. [79]. (B) Geological map of Zakynthos Island modified after the Institute of Geology and Mineral Exploration of Greece (1980) and Avramidis et al. [80]. (C) Aerial view of Keri Lake with the location of the NE and HE sites. (PDF 2443 kb)