Marsili Volcano

Mount Marsili? a submarine volcano belonging to the Aeolian island arc. It is located in the southern Tyrrhenian Sea, about 140 km north of Sicily and about 150 km west of Calabria. It is an immense geological structure, extended for 70 km in length and 30 km in width, which rises for about 2700 meters from the seabed, reaching with the top the altitude of about 450 meters below the surface of the sea. These conspicuous dimensions certainly make it the largest volcano in Europe. Extensive documentation on Monte Marsili ? available in the scientific literature, also on the web (see, for example, the popular video taken from the SuperQuark programme: http://www.youtube.com/watch?v=etJowy17cBo&feature=related).

In recent years this large submerged volcano? been the subject of numerous researches and an extensive scientific debate centered on its dangerousness? and the risks it could pose. In particular, the Marsili ? been indicated as the potential source of a tsunami that would affect the entire Tyrrhenian side of southern Italy. The fear of the researchers, expressed by Prof. Enzo Boschi, president of INGV, is not? both the fact that an underwater eruption can occur, but that an eruption can determine the collapse of a substantial portion of the volcanic edifice, made fragile by its activity? magmatic. The hypothesis? based on data collected by INGV and the CNR Institute of Marine Sciences, published in 2009 and 2010 in the prestigious journals Journal of Volcanology and Geothermal Research (http://hdl.handle.net/2122/5046) and Geophysical Research Letters (http://www.agu.org/journals/ABS/2010/2009GL041757.shtml).

The displacement of a rock mass below sea level due to a landslide can give rise to a tsunami, exactly as occurs during large earthquakes such as the one that hit Japan on 11 March: in the first case the displacement of rock masses occurs for gravitational reasons, in the second case due to the effect of displacement along the fault plane that generated the earthquake. In both cases there is the excitation of the whole column of water above and the generation of a tsunami wave, whose characteristics are a function of the volume of rock displaced and of some other specific variables of the landslide phenomenon (essentially speed? and density of the material). Scholar Steve Ward of the University of California, Santa Cruz, has developed a model of what could happen if a landslide of 10 cubic km detaches from the Marsili building:

http://www.youtube.com/watch?v=8LQpPtj8EIY

The tsunami wave generated by this immense landslide would reach the coasts of southern Italy with a height of up to 20 metres, with catastrophic effects for the coastal settlements located below this height. It would be something similar - but with incomparably larger dimensions - to what? which occurred in Stromboli on December 30, 2002, when a landslide whose size? been estimated in a fraction of cubic km detached? from the side of the submarine portion of the volcano due to the overload caused by the accumulation of lava due to an eruption in progress.

It must be reiterated that that of the researchers ? just a fear, indeed. In fact, it remains to be demonstrated that Monte Marsili is close to reactivation; and even if this happens, the eruption could go almost unnoticed by the population, as evidenced by some important recent submarine eruptions (e.g. the Lohii seamount in Hawaii or the Kick'em Jenny in the Antilles) which have not been accompanied by collapses and/ or from tsunamis.

INGV is doing its best to promote more detailed research that will make it possible to understand exactly what evolutionary stage Marsili is in today and what could be the modalities? of reactivation, cos? to arrive at an overall assessment of its danger?. At the moment its probability? of reactivation ? low - certainly pi? lower than that of the pi? active Aeolian volcanoes - but definitely not anything. Sar? necessary to acquire further and new data - what made more? complex from the distance from the coast of Marsili and its depth? - why? is it possible to take steps forward in the knowledge of what remains of the largest volcano? large in Europe.