Seismicity parameters based on instrumental and historical data are given for 36 seismic sources of shallow earthquakes and for 6 seismic sources of intermediate depth earthquakes in the Aegean and surrounding area (34°N-43°N, 18°E-30°E). These parameters are of two categories. Parameters of the first category are useful for seismic hazard evaluation (a and b values of the frequency-magnitude relation, maximum earthquake magnitude, number of shocks larger than certain magnitude per year) while parameters of the second category are proper for describing the spatial distribution of Seismicity (mean return period, most probable magnitude in a certain time period, moment rate). Shallow Seismicity is highest along the convex side of the Hellenic arc but close to the coast (Ionian Islands, south Peloponnesus, south of Crete, south of Karpathos and Rhodos), in Central Greece (Patraikos-Corinthiakos-Evoikos gulfs, Thessalia) and along a seismic belt which includes the northwestern Anatolia fault zone, the northernmost part of the Aegean Sea and the Serbomacedonia zone. The intermediate depth seismic activity is distributed in two parts of the Benioff zone, which dips from the convex side (Eastern Mediterranean) to the concave side (Aegean Sea) of the Hellenic arc. The one part shows a low dip angle and includes earthquakes with focal depths between 70 km and 100 km. This part has a high seismicity (earthquake magnitudes up to 8.0) and is situated below the inner slope of the sedimentary part of the Hellenic arc (Eastern Peloponnesus-north of Crete-Rhodos). Based on the fact that this part of the Benioff zone is a continuation of the seismic zone of shallow earthquakes along the Hellenic arc and that both zones have the same seismicity, it is concluded that they constitute a continuous seismic belt on which coupling occurs between the subducted eastern Mediterranean lithosphere and the overthrusted Aegean lithosphere. The other (inner) part of the Benioff zone shows low seismicity (maximum earthquake magnitude up to 7.1) with earthquakes of focal depths between 100 km and 180 km. It dips at a mean angle of 38° below the volcanic arc of the southern Aegean Sea and is the result of the subduction of the front part of the eastern Mediterranean lithosphere without coupling with the Aegean lithosphere. © 1990.
