Focal mechanism along the convex side of the Hellenic Arc

The focal mechanisms of eleven large earthquakes that have occurred during recent decades in the Hellenic Arc are determined. For each earthquake the long-period P and SH waveforms were in-verted to estimate the parameters of the best fitting point source, including seismic moment, centroid depth, double-couple source orientation, and source time function. Four of these earthquakes occurred in the northwestern end of the Hellenic Arc and have strike-slip faulting mechanisms with fault planes striking SW-NE. Three other earthquakes from the area of Zakynthos, and four near the Crete island, that is along the Hellenic Arc, are characterized by thrust faulting. Reliable fault plane solutions, already published, are also taken into consideration in order to examine the motion taking place along the whole Arc, using all the available data. The whole data set was separated into four groups, and for each one, the representative fault plane solution determined. It is found that the direction of the maximum compres-sion axis P changes from ENE to NNE going from west to east along the Arc.