[1] These two plate boundaries give rise to two contrasting tectonic styles, extension on east–west trending fault zones with strike-slip tectonics on SW-NE trending fault zones throughout west and central Greece, Peloponnese and the northern Aegean and contractional in the southern Aegean, continuing around to the Ionian Islands.
The south Aegean is the location of the volcanic arc and is characterised by extension.
To the east of Crete along the Hellenic Arc, strike-slip tectonics with some extension become important.
[1] The strongest earthquakes historically are those associated with the Hellenic Arc, although none larger than about 7.2 have been observed instrumentally.
Large intermediate depth (>50 km) earthquakes of magnitude >7 from within the subducting African plate have been recorded but such events cause little damage, although they are widely felt.