THE 1995 GREVENA (NORTHERN GREECE) EARTHQUAKE - FAULT MODEL CONSTRAINED WITH TECTONIC OBSERVATIONS AND SAR INTERFEROMETRY

After the 1995 Grevena M(S) = 6.6 event in northern Greece, we mapped the earthquake fault break in detail. The surface break is small (8-12 km long, 4 cm slip) compared to the moment release of the event. Howe ver, the morphologic and tectonic study of the active faults, in the f ield and using the SPOT satellite imagery, suggests that the earthquak e ruptured part of a much larger fault system including interconnectin g segments. We used SAR interferometry of the satellite ERS-1 imagery to characterize the coseismic displacement field. This shows a kidney- shaped zone of subsidence reaching 30 cm flanked by an uplift zone rea ching 5 cm. We reproduce this field using dislocations in an elastic h alf-space and our observations of the fault system. This requires 1 m slip from 4 to 15 km depth on a main normal fault segment dipping NNW. Our preliminary model includes significant NE-dipping scissors faulti ng at the eastern end of the rupture, clearly seen in the interferogra ms.