New constraints on the rapid crustal motion of the Aegean region: recent results inferred from GPS measurements (1993-1998) across the West Hellenic Arc, Greece

In this paper we present the most recent observations of crustal motion acr oss the entire West Hellenic Are (WHA). These are based on repeated GPS mea surements carried out in the period from 1993 to 1998. The results are pres ented in terms of trajectories and rates, relative to Eurasia. Within these five years southwestern Greece has moved to the southwest by an average ra te of 30 mm/a, increasing from 10 mm/a at the island of Lefkada, in the cen ter of the Ionian islands, to nearly 40 mm/a along the southwest part of th e Peloponnesus and to 35 mm/a on the islands of Crete and Gavdhos. The data provide strong evidence that distributed shear strain starts at the Kephal onia Fault Zone (KFZ), were an anomalously high earthquake activity is also observed. A striking interruption of the motion is seen at the island of S trofades, at the southwest leading edge of the WHA, where a south-oriented displacement of 12 cm was detected, coincident with the M = 6.4 Strofades e arthquake of Nov. 18, 1997. (C) 1999 Elsevier Science B.V. All rights reser ved.