SUBCRUSTAL EARTHQUAKES IN THE NORTHERN APENNINES (ITALY) - EVIDENCE FOR A STILL ACTIVE SUBDUCTION

Previously unreported subcrustal earthquakes have been located up to 90 km depth beneath the Northern Apennines (Italy). These earthquakes occur beneath a sone of abundant upper crustal seismicity, mostly confined to the upper 20 km of the crust. Although there are relatively few well located subcrustal earthquakes, there appears to be a general southwestward deepening of the hypocenters, from the Adriatic to the Tyrrhenian Sea, consistent with other geophysical data which suggest that the Adriatic lithosphere is presently subducting beneath the Northern Apennines.