The 1908 Messina Earthquake and the Messina Straits Seismicity as Shallow Expression of Wide Depth-Range Regional Geodynamic Processes

New tomographic results in the Calabro-Peloritan Arc region show that the Messina Straits area delineates the transition between the only sector where the Ionian slab is in-depth continuous and therefore still capable to retreat (Southern Calabria) and the south-western boundary of the subduction system now interested by continental collision (central-western Sicily). This geodynamic framework produces the seismogenic stress field detected in the Straits crustal structure, characterised by ESE-oriented extension and by minor strike- slip component. Stress field and seismicity analyses performed in the area reveal that the 1908 earthquake source is characterised by normal faulting, is located in the Straits and it strikes about NNE-SSW with the top below Sicilian shoreline and dip toward east. Also, in spite of the very low seismicity levels recorded since the installation of local seismic network (late '70s), the analysis performed on historical catalogue data (CPTI, http://emidius.mi.ingv.it/CPTI/) for the period 1780-2002 highlights that the Messina Straits is one of the most active areas in Italy, also excluding phases of maximum destructive capability.