Detecting Geophysical and Geological Signatures of an unknown Fault in Messina Historical Center (Sicily, Southern Italy)

The analysis of seismic noise measurements indicates an evident shift in the Site Resonant Frequency along a NW-SE axis that crosses the historic center of Messina (Sicily, Southern Italy). This shift implies a clear lateral variation in sediment layers from the southwest to the northeast along the axis. Moreover, it suggests the existence of an unreported fault, differing from the widely accepted NNE-SSW primary structural system attributed to the M 7.1 earthquake of December 28, 1908, the strongest earthquake occurred in the Messina Straits area (southern Italy) in historical times.

Further evidence supporting this NW-SE fault is provided by surface geological investigations and comprehensive analyses of morphological and Digital Terrain Model data. While geological observations clearly suggest normal faulting, they do not explicitly reveal any potential strike-slip components. The activity of this NW-SE fault extends back to at least the Middle Pleistocene, as inferred from stratigraphic evidence and borehole data, possibly persisting into the Upper Pleistocene.

This newly detected fault warrants more extensive investigation in the near future to ascertain its precise spatial extent and contemporary dynamics, particularly regarding its potential for seismic activity.