| Abstract: | A new fault-plane solution map of the Italian peninsula is presented in this paper. The earthquakes analyzed are included in the period 1905–1980, with magnitudes ranging 4–7, 75 earthquakes are located in the crust, while 31 are related to the deep and intermediate zone of the Calabrian arc. The large seismic events of the Italian peninsula are generally associated with normal faulting, while strike-slip motion is mostly related to small earthquakes, located along lateral segments of the mountain chain.The deep and intermediate earthquakes of the Tyrrhenian Sea indicate predominant down-dip compression, and strike-slip motion at the boundaries of this Benioff zone. This last is interpreted as a remnant of a subduction zone, active since Oligocene, extending to 500 km depth, with a very small lateral size (about 300 km). The present tectonics of this Benioff zone is strongly conditioned by the lateral bending, more so than the gravitational sinking process.The coexistence of thrust and normal faulting motion associated to the earthquakes, within a few tens of kilometers of each other, seems to be explained by the strong lateral inhomogeneities of the crustal rocks present in this region, more so than to the depth of the seismogenetic zone and the nature of the faulting process. |
