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 across the entire West Hellenic Are (WHA). These are based on repeated GPS measurements carried out in the period from 1993 to 1998. The results are presented in terms of trajectories and rates, relative to Eurasia. Within these five years southwestern Greece has moved to the southwest by an average rate of 30 mm/a, increasing from 10 mm/a at the island of Lefkada, in the center of the Ionian islands, to nearly 40 mm/a along the southwest part of the 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 Kephalonia Fault Zone (KFZ), were an anomalously high earthquake activity is also observed. A striking interruption of the motion is seen at the island of Strofades, 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 earthquake of Nov. 18, 1997. (C) 1999 Elsevier Science B.V. All rights reserved.