Active Tectonics and Seismicity in Greece

Greece is classified as one of the most active regions of the Earth’s surface due to its intense geotectonic activity. The broader Aegean Sea area and surrounding lands form a region characterized by high seismicity and complex tectonics controlled by the movement of convergent plate boundaries. The closure of the Tethys oceanic basins in the region resulted in crustal thickening and consequent post-orogenic extension and magmatism. From the Pliocene until recent times, the extensional processes continued in the broader Aegean Sea area. The current geodynamic processes are controlled by two major structures, the Hellenic trench (along the active subduction of the African plate) and the North Anatolian Fault system, which terminates in the North Aegean Sea. Neotectonic studies and the focal mechanisms of shallow earthquakes indicate that the active faults can be divided into the following categories: (a) low-angle thrust and steeper reverse faults along the Hellenic trench; (b) E–W oriented normal faults along the Greek peninsula, the back-arc Aegean area, and western Turkey; (c) N–S trending normal faults along the Hellenic orogen and the upper Aegean plate, mainly south of the Hellenic volcanic arc; and (d) strike–slip faulting in the Northern Aegean, Epirus, the Ionian Islands, and western Peloponnese.