Marsili seamount: tsunami threat for Southern Italy? 30 March 2010

Mount Marsili is a 3000-metre high seamount beneath the Tyrrhenian Sea, 150 km south-west of Naples. Marsili is active and recent research has indicated signs of restlessness (see this 2006 paper in PDF), although the risks of any dangerous eruptive activity are very slight). In an interview with the Italian newspaper Corriere della Sera, the director of the Istituto Nazionale di Geofisica e Vulcanologia (INGV), Dr Enzo Boschi, has reminded everyone that Marsili is active and that there is a potential threat of an eruption/collapse generating a tsunami that would threaten Southern Italy:

It could happen tomorrow. The latest research says that the volcanic edifice is not strong and its walls are fragile. Furthermore we have measured the magma chamber that has formed in recent years and it is of large dimensions. All this tells us that the volcano is active and could erupt unexpectedly.

According to the article, observations indicate that hydrothermal emissions from vents around Marsili have become more intense recently, and evidence of landslides discovered by the oceanographic research vessel Urania last February ‘indicate an instability impossible to ignore’. Dr Boschi warns that a flank collapse at Marsili ‘would displace millions of cubic metres of material, which would be capable of generating a wave of great power’. Marsili is currently unmonitored, observes Dr Boschi: ‘A network of seismometers should be installed around the edifice, connected on land to a volcano monitoring centre. But this is beyond the budget’.

And it seems reasonable to suggest that the budget is what this article is actually all about. Despite the new attention this story will bring to Marsili as it gets cut-and-pasted around the web, there is nothing substantially new here, as Aldo Piombino notes in a very comprehensive post published on his blog today. No new activity lies behind this report, and nor has the potential threat, such as it is, changed in any way. The novelty, he observes, is in public attention being drawn to the need to monitor Marsili, which has been invisible in every sense as far as the Italian public is concerned.

Undersea volcanoes tend to be out of sight and out of mind. Writing in 2008, Aldo Piombino called Marsili ‘one of the least-known of the huge volcanic systems of Europe’, and argued that more attention must be paid to this active and potentially very destructive underwater giant:

It is statistically very unlikely that in our lifetimes we will see an explosion of Marsili, and even less likely that we will see a tsunami caused by a landslide on its flanks, but it is to be hoped that it will be placed under close seismic and geochemical surveillance, as with other active Italian volcanoes. I believe that it is necessary for civil protection and for science that one of the largest volcanoes in Europe is better understood.

Boris Behncke of the INGV discussed Marsili’s activity in the course of his Q&A on Dr Klemetti’s Eruptions blog last year, but also remarked that monitoring Marsili was not a priority for the INGV [UPDATE: in fact that is not what Boris meant. He meant that Marsili has not been a priority for the Italian authorities, Civil Defence, and the Italian public, rather than the INGV – see his comment at Eruptions]. Dr Boschi’s comments today would seem to indicate that that has changed. Aldo Piombino observes today that the technology is available within the INGV to monitor Marsili directly from the seabed using new broadband seismometers transmitting to land-based monitoring stations, and supports Dr Boschi’s call for full monitoring of the volcano. But that cannot happen without money, which is more likely to be forthcoming if the potential (and real but, it must be emphasized again, very remote) dangers of a tsunami-generating collapse at Marsili are stressed – hence the Corriere della Sera article.

So, it seems that a push has begun within Italian volcanology to get Marsili wired up for continuous and comprehensive monitoring. Let us hope it succeeds.

UPDATE 30 March 2010: Dr Erik Klemetti has more on Marsili at Eruptions, and Boris Behncke, himself of the INGV (Dr Boschi is Boris’s boss), has an illuminating comment here.

News
Torna a far paura il vulcano sommerso nel Tirreno – Corriere della Sera, 29 March 2010
Undersea volcano threatens southern Italy: report – AFP, 29 March 2010
Il Monte Marsili, un gigantesco vulcano nascosto dalle profondità del Mar Tirreno – scienzeedintorni, 4 April 2008
Finalmente alla ribalta il più grande fra i vulcani sommersi nel Tirreno, il Monte Marsili – scienzeedintorni, 29 March 2010