Bridge over the Strait, a study shows that active faults separate Calabria and Sicily

Calabria and Sicily are progressively moving apart due to a system of faults present in the seabed of the Southern Ionian Sea, which are causing the earth's crust to slowly sink off the Strait.This is what emerges from the first results of a study carried out by members of the National Research Council (CNR), conducted on the oceanographic vessel Gaia Blu, in which they were identified very large cracks on the seabed of one of the most active seismic zones on the European continent.The research, which aims to increase knowledge on geological processes in the southern Ionian Sea, was carried out off the coast of the Ionian Sea between Etna and Greece.Although the area is distant from the Strait, the attestation of the movement of separation between the crustal blocks is already producing significant repercussions on the public debate regarding the safety and sustainability of the Bridge over the Strait of Messina, work on which - at least according to the government's intentions - should start in the coming months.The Stretto di Messina SPA company, concessionaire for the design, construction and management of the Bridge, reacted by downplaying the results of the study and confirming the forecasts of the definitive project of the work.

As stated in a press release issued by the Cnr, which has illustrated what was learned during the research, «using cutting-edge geophysical technologies» was «identified a field of underwater reliefs aligned along deep cracks in the southern Ionian seabed, where a system of faults is progressively distancing Calabria from Sicily».Specifically, these are "diapiris", or "sediments that rise from deep areas, visible only with ultrasound scans of the subsoil", but also "mud volcanoes" that form "when deep material rises towards the surface together with fluids and gas", giving rise in certain cases to "real fluid and viscous eruptions".The images clearly highlighted the morphologies of these reliefs, which «show indications of recent eruptive and tectonic activity».The aim of the scholars will now be to "explore the nature and origin of the material that rises along these large lithospheric faults", trying to understand "how these influence the generation of earthquakes in one of the most seismically active areas in Europe".Stretto di Messina SPA immediately reacted to the discussion that followed the publication of the first results of the study, writing in a note that «the identification of the geological formations mentioned it is not relevant for the feasibility of the bridge over the Strait of Messina", being "known" that "the Sicilian and Calabrian coasts are subject to an albeit minimal removal widely considered in the definitive project of 2011 and in its update of 2024".The company has confirmed the forecasts of the Final Project, highlighting that «the differential movement between the two sites chosen for the pylons (Calabria-Sicily) is less than 1 mm/year».

However, it seems too early to draw conclusions.The sediment and rock samples taken by Cnr researchers will be examined by scholars in the coming months.Only after some time will it be understood whether further elements will be added to the list of recommendations already made by the technicians of the scientific committee who, despite giving a positive opinion to the update report, last March they had made 68 findings.In addition to the need to carry out further checks on the effects of the wind, an update of the "microseismic zoning" and recommendations on the steels with which the tie rods will be made, they stood out in fact observations on the "geology of the seabed", with respect to which a «integration of the most recent studies on the seabed of the Strait of Messina and surrounding areas» in consideration of «recent studies on faulting, deposits and shapes that are possible indicators of recent tectonic activity».In the last year, the definitive 2011 project from which the executive chose to start again was updated by the Eurolink consortium, which in 2005 had won the tender for the works.In the meantime, the overall cost of carrying out the work has risen to 14.5 billion euros.

[by Stefano Baudino]