Analysis of eleven years of deformation measured by GPS in the Corinth Rift Laboratory area

Abstract

GPS (Global Positioning System) data collected in the Corinth Rift during eleven campaigns between 1990 and 2001 provide velocities of 57 points with ∼1.5 mmyr−1 accuracy. Peloponnesos moves at 30 mmyr−1 to the N215° E with respect to a fixed Europe. Extension across the rift is accommodated in a narrow band offshore. Its rate increases from east to west and is 16 mmyr−1 near Aigion. Both sides of the rift behave as clockwise rotating blocks with rates of 7±0.5° Myr−1 and 2.8±0.8° Myr−1, respectively for the northern and southern blocks. After removing block rotations, the northern block shows a north–south extension rate of 120±50 nstrainyr−1, whereas the southern block indicates the internal deformation is still inside the error bar (<20 nstrainyr−1). The strain accumulation across the major faults located along the southern coast of the Corinth Gulf is less than 1 mmyr−1. This implies long recurrence periods for large earthquakes on these faults.