Submarine volcano off Italy may be a tsunami threat

Map showing the location of submarine volcano Marsili, near the Italian coast. Image from INGV.

The subject of submarine volcanism near Italy has come up before here on Eruptions but now it has made the jump into the worldwide media after some claims made by Enzo Boschi, president of the National Institute of Geophysics and Volcanology (INGV).

The long and short of what I can tell from the articles is that Marsili, a submarine volcano in the Tyrrhenian Sea, could be a threat to create a significant tsunami that would hit Italy (amongst other Mediterranean countries). The volcano lies only 150 km / 90 miles to the southwest of Naples and is under ~450 meters / 1500 feet below sea level. The fear is that an eruption of Marsili would cause part of the edifice to collapse, producing what could amount (in a worst-case situation) to an undersea version of the Mt. Saint Helens 1980 eruption. It could also just suffer from edifice collapse, producing a tsunami similiar to what happened at Unzen in Japan in 1792.

Now I am no expert on the state of research on some of these submarine Italian volcanoes, but some of the articles seem to suggest that the volcano is "ready to erupt". My favorite line might be from an AFP article that states "The Marsili volcano, which is bursting with magma, has "fragile walls" that could collapse". I've never heard of a volcano as being "bursting with magma," but I fear something could have been lost in translation along the way. The evidence presented in the article does suggest that Marsili could be more of a threat to Italy than previously thought, but I fear that the following quote from Boschi is being liberally interpreted:

"Our latest research shows that the volcano is not structurally solid, its walls are fragile, the magma chamber is of sizeable dimensions. All that tells us that the volcano is active and could begin erupting at any time."

(my emphasis).

Now, I read that final phrase as meaning that it is an active volcano, thus future activity is likely - it could be soon, it could be hundreds or thousands of years from now, but the volcano is likely not extinct. However, my guess is that many of the news outlets read that phrase as "it is going to erupt very soon!"

If you want to see some excellent dissection of the Marsili reports, head on over to the Volcanism Blog. You can also see some additional comments on this news from Boris Behncke. For now, I think we can all agree that Marsili should be on our radar as a volcanic threat to Italy, but some of the headlines out here (e.g., "Volcano tsunami could engulf Italian coast 'at any time'"), as usual, are a little over-the-top.

{Thanks to Aldo Pombino for some of the links in this post.}

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First off, I want to thank Dr. Behncke for taking the time to answer your questions - and also, thank you to all who sent him some thought-provoking questions. In fact, the questions and answers take up about 12 pages of text, so the Q&A will be divided into two parts. If you want to see one…
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Here is Part 2 of the Q&A with Dr. Boris Behncke. You can also check out Part 1. Undated image of Stromboli in eruption. (Shirakawa Akira) 1. Would a large scale eruption (VEI 5 or greater) of Mt. Etna like the ones occurred in 122 BC and 1500 BC (disputed) be possible again in the foreseeable…
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There was a comment in the previous thread that said "Marsili may be waking up", following the surge of news reports. I should rectify that currently there is no sign of Marsili waking up (also because there is no instrument to record such signs even if they existed), although in 2006 quite intense seismic activity was recorded by temporarily deployed ocean-bottom seismometers. These signals may have been related to eruptive activity (amongst others, it included the famous "tornillo" events that Galeras volcano in Colombia is notorious for). The concern is that it *may* wake up sooner or later, we don't know anything at all about its current state because it is not monitored and all this humdrum about Marsili is an effort to get funding for monitoring. Which in my opinion is definitely warranted - and if in a previous comment I said that Marsili was not on the high priority list, that referred not so much to the INGV than to Civil Defense and the authorities (and more generally, the public as such). I think the INGV would be happy to be capable of monitoring ALL volcanoes that have the least little bit of a probability of erupting, and funding is far from sufficient, go figure in Berlusconiland. We've got a number of volcanoes that should not be considered totally extinct, and which are not specificaly monitored, such as the huge calderas of Sabatini and Vulsini in Latium, not far from Rome. Even at Etna, a couple of seismic stations recently had to be disactivated due to lack of funding, and they were closest to the area where shortly thereafter, in December 2009, one of the most energetic seismic swarms in recent decades was recorded (without, fortunately, resulting in an eruption).

Again, I consider the chance of a catastrophic event at Marsili relatively small but the possibility exists, and this warrants monitoring and some planning by Civil Defense and authorities.

When you are in a managerial position, you learn very quickly how to handle journalists, to make them report what you want reported, or you do not last long at all. To me, it looks very much as Director Boschi has very skilfully exploited this opportunity by a clever choice of words - "could + at any time", which to a journalist would mean "will + very soon". At the same time, he has kept his own back free as he can fall back on what he actually said and cannot be held responsible for journalistic interpretation. Dr Behncke on another thread here commented upon this and said that it sounded as if Director Boschi was out for funding for further research.

Let us congratulate Director Boschi and hope he receives the funding!

@Boris, politics, as usual, in Italia. :-D I do understand some of that and we have discussed it before. I knew a man that lived across the street from the Vatican and he had no use for voting here in the US, though he did register, but too late to vote! I wish he was still with us (he had liver cancer, stage 4)as he was a very intelligent and decent man that had good views on things. I miss him.

Anyway, maybe funding will occur "sooner or later".

Maybe I better clarify that. He grew up across the street from the Vatican.

Hi boris, very good.
If the Boschi interview will be useful for finding money to make a monitoring system of this volcano I will be very happy.

>However, my guess is that many of the news outlets read that phrase as "it is going to erupt very soon!"<

Probably true. Back in another life I stationed as a reservist at a US Coast Guard command center. Since we directed search and rescue for the district we often had to field media questions. One thing we were told by public affairs was "never speculate", because that could be reported as a definitive statement. For example is a fishing boat went missing, we might suspect (among other things) a large hatch left open in bad weather. But if you said on the record (before any investigation) that was a possibility, it could be reported as, "Coast Guard blames hatch in missing trawler."

The problem with volcanoes and other natural phenomena is that we have to speculate about what will happen. However, as Erik and Boris have said many times we must emphasize the most likely events and point out the difference between informed speculation and wild fearmongering.

However, this still won't end the sensationalism due to the nature of news reporting. It will be a never ending battle.

Ulrich D put up a link on the most recent Iceland Update topic -… - where the following quote occurs:

"Boris Behncke of the INGV discussed Marsiliâs activity in the course of his Q&A on Dr Klemettiâs 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]."

It is yet another illustration of how careful the professional must be when expressing an opinion in print, even if it's "only" on a blog. Also, congratulations to both our host and Dr Behncke for being quoted!

Quite apart from the positioning that comes with media exposure, I think there is indeed a woeful ignorance of the threat of seamounts in general. It's very much a case of out of sight, out of mind. And Marsali looks like a pretty good case in point.

There is a whole string of them between along the Kermadec Ridge and some of these have some pretty whopping calderas on them. McCauley Island is sheathed in a pretty substantial ignimbrite cover. I bear this in mind when we calculate the relative frequences of major eruptions. I reckon you could at least double that number if all submarine eruptions were considered. The only question is how many of them are close enough to the surface to turn into subaerial jobs. Might be quite surprising.

By bruce stout (not verified) on 30 Mar 2010 #permalink

First of all, I found a headline about Marsili on the Daily Telegraph that is pure delight. Not only could southern Italy be engulfed, it could be sunk. We should no longer envy California.…

Oh yes, as someone working in this sort of business you have to be extremely careful in choosing your wording. When Etna erupted in 2001, some of the emitted lavas carried abundant chunks of sedimentary rock (sandstone) with them, which had been entrained when the ascending magma broke through a prominent and well-known layer of sandstone that lies below the base of the volcano. I told reporters, in an attempt to be not-too-scientific, that these rocks were older than Etna, and upon further questioning, stated that Etna had an age of about half a million years. Next day the news was all over Italy, saying that Dr. Boris Behncke had discovered that "sandstone half a million years old" had been erupted from Etna. (These sandstones are actually many many millions of years old.) Luckily this was not a really serious incident, it brought me a few smirks from some colleagues, but on that occasion I noted for the first time how easily things you say can end up in the news media in a very contorted way. I guess my boss Boschi and many other experienced colleagues could write a book about such episodes.

Wishing I could reply to a specific post. To EKoh.. God loves the Coasties and so do I. ;-) Your work there is not unappreciated.As for funding, any means to achieve that end is acceptable in my book even if it means lending credence to the doomsday screaming journalists. IMHO.

""A rupture of the walls would let loose millions of cubic metres of material capable of generating a very powerful wave," Mr Boschi said."
(Daily Telegraph article)

If this is indeed Director Boschi verbatim, it's pretty conclusive that he is out politicking for funds - "millions of cubic metres" seems far more impressive than "1/1000 of a cubic kilometre", doesn't it... :)

Erik, maybe sometime you could provide a description of how submarine volcanoes are actually being monitored. This would be particularly interesting to the engineers and other gear-heads that follow your blog. I've seen various different descriptions in various journals, but the technology seems to be immature compared to the land/space based monitoring we're more accustomed to (I'm thinking about the spiders on St. Helens). As noted before, if Mr. Boschi's remarks shake loose more funding for this kind of work it could result in many direct and secondary benefits for volcanologists in Italy are around the world.

We would rather pay for popcorn than monitoring.

More than ever before, journalists seem to be coming from the ranks of frustrated novelist/screenwriter wannabes. The news isn't as exciting as a fictional tome or a disaster flick, a la "2012"? Simply 'embroider' the words a voila!--the great American novel masquerading as a news story. The news media can't blame THIS kind of writing on a science-illiterate public. Leading your audience around by the nose with sci-fi tales instead of sober science reporting is an abusive, self- aggrandizing, "Gee, maybe THIS will get me that Pulitzer" brand of journalism. As for those who seem to say that anything done to get funding is A-OK? Since when is it OK to scare the populace half to death by consorting with the sensationalistic press? Maybe there currently IS no better way, but that still doesn't make it RIGHT.

I think that I have understood why Boschi has said these words.
in Italy science research situation is in a very dramatic stage. More, Boschi has been involved in a war against mr.Bortolaso, the chief of the civil defense, now blamed for corruption. He wanted to take from INGV the seismometers net.
Many italan people suffer of under-information because quite all the news in TV are made by Berlusconi-friendly journalist and many people does not read papers. These journalists show another country in which all is good and there is no crises. The government has an old mind, made by attorney-at-law, literature man or businessmen without any scientific knowledge (and the most blame science as unuseful: letters and art are more important).
So a scientist has only one way to obtain money: he must demostrate that there is a danger.

Just for the record, here's a verbatim and complete translation of the original interview with Boschi on Corriere della Sera, with a tiny little bit of editing [brackets]. It does have a couple of pompous and fuzzy bits to it, and the title reads "The undersea volcano in the Tyrrhenian [sea] is again cause of fear"; that's actually the most sensationalistic part of it. See for yourself.

âIt could happen tomorrow. The latest research tells us that the volcanic edifice is unstable and its flanks are fragile. We have furthermore measured the magma chamber which has formed during the past few years and which has large dimensions. All this indicates that the volcano is active and could erupt suddenly.â
Enzo Boschi, president of the INGV, even though cautious, sounds concerned when telling of the results of the latest research campaign carried out on the Marsili [seamount], the largest volcano of Europe, lying undersea off the coast of the [Italian region] Campania.
From the seafloor it rises to a height of 3000 m and its cratered summit lies 450 m below the sea-level. Its impressive structure is 70 km long and 30 km wide. It is a hidden monster whose real face has been revealed only thanks to bathymetric surveys. Around it a number of hydrothermal emissions have been observed, with a frequency that is more elevated lately, and these, together with the weak structure of the volcano slopes, could cause collapses that would be of more serious concern than a possible eruption. Two events, fortunately of small magnitude, have been recorded recently.
âThe rapid collapse of a significant quantity of materialâ, explains Boschi, âwould trigger a powerful tsunami that would affect the coasts of Campania, Calabria, and Sicily, provoking a disasterâ. The instruments have revealed the shape of the chamber of incandescent magma within Marsili, which has grown and reached a size of 4 x 2 km [height? width? length?]. It is like a boiling kettle with its lid well shut.
Since years Marsili has been under heightened surveillance, after emitting ominous signs. Its history is lost in time and the time of its last eruption is unknown: certainly it occurred long ago. But the signs it has given have stimulated research and the [results of the] latest campaign initiated in February with the vessel Urania of the Italian Research Council, has led to heightened concern. Landslide deposits that were discovered point to an instability that must not be ignored. âThe failure of the slopesâ, says Boschi, âwould mobilize millions of cubic meters of material capable of triggering a massive wave. The indicators that have been revealed are very clear now, but still we cannot make any forecasts. The risk is real but difficult to evaluate.â
The reason for this [difficulty] lies in the geographical position of the volcano [deep below the sea-level]. Etna, over the past few years, has been covered with a dense network of instruments capable of giving warning when an eruption is imminent, at least with a bit of a lead time. Marsili is not only below the sea, but it also lacks this sort of instrumentation ready to listen to its signs of bad intentions. It is necessary to install a network of seismometers around the volcanic edifice, linked to a control center on land. But all this is beyond our financial capacities. With the currently available [economic] resources, a few instruments could be afforded, but not the dense network that is warranted.
âWhat is neededâ, concludes Boschi, âis a system of continuous monitoring, to guarantee reliability. But it is expensive and complicated to install. What is certain is that at any time something irremediable could happen but we have no means to recognize it [in time].â

This is nothing new in journalism. Back in the late 60s and early 70s, my father was in charge of training the Apollo program astronauts in geology. He took them to various locations in the pacific northwest including Newberry Caldera, the three sisters, etc. They had a press conference to answer questions about the trip from the local press. When asked about why they were up in the cascades, my dad answered something to the effect of "we think the recent volcanic deposits from the dormant volcanoes in the cascades may be similar to what they will see on the moon."

When the reporter tried to correct him by saying the volcanoes were extinct, dad said that no, they were just dormant and could erupt again. That led the reporter to start questioning him about which ones were dormant and how soon they could erupt. My dad kept trying to deflect them by saying that there would be lots of warning signs and we would know days or weeks ahead of time. But the reporter persisted and finally got him to admit that it was theoretically possible that My Hood could erupt next week. The next question was what would happen if it did, to which dad answered "it would dump a lot of ash on Portland".

The headline in the paper the next day was "NASA Geologist Predicts Mt Hood to Erupt, Portland to be Buried in Ash!". Dad got a stern talking to from Deke Slayton the next day about not getting off topic with the press...

Not much has changed since then in journalism.

Boris - thanks for posting that translation!

Tex - that is a great story! Thanks for sharing it.

Actually, what are the risks of seamounts in terms of severity and frequency?

off the top of my head:
caldera collapse forming a tsunami
flank collapse forming a tsunami
large explosive eruption causing a tsunami and possible ashfall (or pf also causing a - you guessed it - tsunami)
(... what am I missing ?)
ergo.. the greatest risk is probably that of a major eruption causing a tsunami which as everyone above has stressed is very unlikely. However, wouldn't this risk best be countered by a tsunami warning network like the one in the Pacific? Is there anything comparable in the Med? I think the Germans were instrumental in installing the system in the Indian Ocean, it would be ironic if a European country were to ignore the risk at home.
Finally how high is the tsunami risk in the Med actually? There is a lot of seismic activity in the eastern Med and I would have thought the topography (closed body of water) would accentuate the impact of any tsunami.

By bruce stout (not verified) on 30 Mar 2010 #permalink

@Bruce, the Mediterranean is a classical tsunami environment with a long, long history of devastating tsunamis. Most of them are earthquake related, but several large volcano-induced tsunamis are also known. Stromboli in the Aeolian Islands off northern Sicily has undergone repeated partial flank collapse in the past millennia, each probably generating a major tsunami; a small collapse in December 2002 caused a tsunami 10 m high when it flooded the lower portions of Stromboli island, causing considerable damage. Santorini during its ~1650 BC ("Minoan") eruption produced tsunamis in the eastern Mediterranean that may have even left a trace in the Bible, and a large flank collapse of Etna about 8000 years ago is suspected to have generated a similarly massive if not even larger tsunami. Historical earthquakes have regularly been followed by tsunamis, from Spain to the Middle East. The most recent of these events was the 1908 Messina (Sicily) earthquake with 80,000 to 100,000 fatalities, many of them due to a large tsunami. So yes, this is a high-tsunami-risk area, and after the 2004 Indian Ocean disaster there was much talk about establishing a tsunami warning system in the Mediterranean but I haven't heard too much about this lately. This may be in part due to my incapability of following all developments in the field. So I hope I just missed that bit. But it's not been much in the news, which is why I suspect nothing much has happened, given the current crisis and the stark disinterest in particular of the Italian government toward research.

Another problem with the Mediterranean is its size. With tsunamis you need a decent amount of ocean between you and the wave-triggering event to get some warning. The Mediterranean is simply not that big. At least with the Straits of Gibraltar any tsunami will have a limited shoreline it is able to hit and do significant damage to.

Looking at the figures for that volcano and the distance to the Italian coast it is simply inconceivable that a warning could be provided in time to do anything beyond superficial good. If anything this volcano could be said to present more of a danger to Naples than Vesuvius, Campi Flegri or Ischia do in some scenarios. At least with those three volcanoes there are monitoring stations which are likely give at least some warning of an upswing in activity. With this monster there could be a flank-collapse event and the first people would know of it would be the withdrawing of the sea on the Italian coast prior to the tsunami hitting.

By David Newton (not verified) on 30 Mar 2010 #permalink

I couldn't find a realistic cutoff for depth, regarding tsunami risk, but the vast majority of these destructive waves are caused by earthquake or coastal or submarine landslide, with much less risk associated with submarine volcano and least risk from large extra-terrestrial bolide collision with the sea surface at critical marine depth.

I did find quite a few citations that state that many seamonts are too deep to cause tsunami.

Looking at Italy's economy

And knowing that, like the US and other nations facing substantial public debt, quite a bit of it (private finance initiative canoodling) still lies hidden from public inspection.

The Marsili SeaMount may be a ticking time-bomb, but as Erik flatly states, the duration before failure is unknown. The Italian economy is near zero growth, it has succumbed like many others to the lure of securitisation instruments or asset finance transactions to finance costly public support programs.

Maintaining status quo for geological monitoring may be as Good as It Gets, for the time being.

If they want to be creative, INGV could explore relatively low-cost sensor-probe deployment by remote robotic modules, with program development under joint programmatic support from International Big Science (space, climate, earth science agencies) with similar need. Japan, Canada, US, Europe and UK, China, Russia and even Iceland would have vested interest in this type of monitoring effort if it could be made global, to share costs and monitoring load.

The driver? Assess a subset of submarine volcanic activity with the goal of estimating CO2 offset by iron and mineral nutrient emissions-fed algae. Recent reports suggest this mechanism is a substantial player in carbon dioxide sequestration in the oceans. Climate modeling efforts will need better submarine volcano emissions estimates, and in return, the geologists, geochemists and volcano-heads get seismic, gas and GPS data.

Tsunami warning system in the Mediterranean:

March 24, 2010. Harris Corporation's Maritime Technology and Services to Aid New Tsunami Warning System in Mediterranean Sea.

'This system will consist of an array of seismometers and very sensitive pressure sensors installed on several hundred kilometers of seafloor and connected to a Harris OceanNet⢠buoy moored about 80 kilometers off the southern coast of Cyprus. The buoy is one element of the Offshore Communications Backbone (OCB) project that Harris is developing with CSnet. OCB is a modular, expandable system of seafloor equipment, power, communications and services for long-term, deep-ocean observation.'

'Harris is supporting CSnet International, Inc., whose CSnet (CYPRUS) Ltd. affiliate is teamed with the Oceanography Centre of Cyprus to develop and deploy a prototype Tsunami Warning and Early Response system for Cyprus (TWERC).'

Project went on the books in 2008, set for deployment in 2011.

Boris, you may want to have your boss get in contact these folks to see if there are plans to put sensors near the seamount chain that would aide INGV monitoring efforts.

If so, you may want to craft a carefully-worded statement to HAND to the press, as an agency response to growing public concern over the seamount.

@passerby, sounds like the underwater version of swords into plowshares. Not so much money anymore in deploying military sensors, so why not use much of the same technology for the public safety market.

@Mots, I think you hit the nail on the head! ;-D

Could anyone tell me if this is just noise or something more? quake.
There is a bit of a signal at surrounding stations also.

@Someguy. Looks like wind noise to me. I, however am not a Volcanologist.

By Dasnowskier (not verified) on 30 Mar 2010 #permalink

I am not an expert either but I do keep an eye on those seismographs and check them several times a day, every day and I have been checking them that way for the past 5 years. I think it's some noise, some looks like they may have ice on some of the antennas too. There have been 2 quakes in the past 24 hrs close to Mammoth Hot Springs that didn't even register on that webicorder. I think several of them are not working correctly and haven't for about a week....The activity has been picking up there over the past few days though....look back at yesterday for YMR and you will see a lot of activity and it wasn't just noise.

I know some strange signals come from this station usually during drive times. This has been the nicest weather day in a while so it would surprise me that wind or ice noise would be causing this today.

There is a recent scientific paper on that, showing Marsili is a collapse-prone volcano. I think it is where "the fragile walls" come from. Access to geophysical research letter is required to read the paper:
Caratori Tontini, F., Cocchi, L., Muccini, F., Carmisciano, C., Marani, M., Bonatti, E., Ligi, M., Boschi, E. (2010), Potential-field modeling of collapse-prone submarine volcanoes in the Southern Tyrrhenian Sea (Italy), Geophysical Research Letters, 37, L03305, doi:10.1029/2009GL041757.

Chris Rowan, over at Highly Allochthonus blog, was nattering today about Aquila area Bufo toads maybe not being such reliable seismometers. He links back to a former post that describes the unexpected stretching tectonics involved in the lethal Aquila 2009 earthquake. You would expect an EQ compression mechanism, but this is a complex back-arc system. Good graphic, excellent explanation. See:…

Boris Behncke...thanks for the write up...i would think that something 70km x 30km x 3km should be!

By Wayne Williamson (not verified) on 02 Apr 2010 #permalink

"Our latest research shows that the volcano is not structurally solid, its walls are fragile, the magma chamber is of sizeable dimensions. All that tells us that the volcano is active and could begin erupting at any time." - that is so true. I think you put alot of effort in this presentation. It was very informative!

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