In this article, paleoseismological studies carried out in the Aegean region during the past decade, mainly on faults occurring in mainland Greece, are reconsidered and their results re-evaluated. We focus on active normal faults and particularly on the principal seismotectonic parameters, such as the coseismic displacement associated with past events and the lengths of the seismogenic structures. Based on new field observations, existing data, and several assumptions, we attempt to calculate the maximum seismic moment possibly associated with past earthquakes and documented from paleoseismological studies. These seismic moments are compared with those estimated from historical earthquakes for which both maximum vertical displacement and surface rupture lengths are known. Similarities and differences of the two data sets are discussed, and we show that paleoseismologically calculated magnitudes and displacements per event appear to be systematically underestimated in the Aegean region, as is their seismic potential. For selected faults, we also obtained reliable values of the recurrence interval of moderate to large earthquakes and estimates of the slip rate.

Abstract Northern Greece is an intracontinental region behind the Hellenic subduction zone, with widespread seismic activity (ranging from low to high), with strong destructive earthquakes of M ≥ 6.0 in historical to recent times. Geological and seismological data indicate that recent seismic activity is mainly localized along large, inherited, fault zones, which have transected Northern Greece since Oligocene—Miocene times. The main active fault zones in Thrace, and Eastern and Central Macedonia strike approximately east—west, with lengths of 40–120 km. Fault segments strike WNW—ESE to ENE—WSW and range from 10 to 30 km in length. In Western Macedonia the main active fault zones strike NE—SW to ENE—WSW with lengths of 40–60 km and consist of 10–30 km segments. The region's strong earthquakes are usually associated with reactivation of these fault segments and are estimated at M = 5.6–6.5. Focal mechanisms and fault-slip data from the fault zones indicate a change in the trend of extension axes from NNE—SSW in Eastern Macedonia-Thrace to NNW—SSE in Western Macedonia. Thus, neotectonic and seismological data suggest that variations in fault patterns, as determined from the large inherited fault zones transecting Northern Greece, are the major factor governing this change in the trend of maximum extension. This interpretation is consistent with the long-lived arcuate shape of the Hellenic subduction zone.