Microseismic activity and seismotectonics of Heraklion Area (central Crete Island, Greece)

A seismological network of 10 portable analogue stations was installed in the area of Heraklion (central Crete) from September to December 1995. During this period, more than 1000 events were recorded by at least 4 stations with magnitudes ranging from 0.5 to 4.6 and depths up to 70 km. Analysis of 336 well located events revealed high seismic activity. In the onshore area seismicity is shallow (<20 km) and concentrated along the eastern margin of the Heraklion Basin and in the Messara graben to the south. Seismicity decreases rapidly from east to west, with practically no events located along the western boundary of Heraklion Basin. Epicenter distribution indicates that microseismicity is closely associated to the tectonics of the region. Significant seismic activity was also observed in the southern offshore area, restricted north of the Hellenic Trench and related to the subduction process. The determination of different types of focal mechanisms in the area indicates that the investigated region is characterized by complex tectonics related to the southward subduction of the African plate and the northward extension of the Aegean lithosphere. 1999 Elsevier Science B.V. All rights reserved