The Decade Volcano Programme

Fig.1 The dead of Herculaneum, burnt to death by 800-centigree hot pyroclastic flows from Vesuvius AD 79 (O Louis Mazzatenta, National Geographic)

The volcanic eruptions of Mount St Helens in 1980 and Nevado del Ruiz in 1985 made the general public aware of the dangers of co-existing with a large and potentially lethal volcano. It doesn’t take much imagination to see the possibilities of a lateral St Helens-type blast on a population of a great city as unaware of the hazard as the unfortunate citizens of Armero, Colombia. Blasts from the past such as Vesuvius 79 AD eruption that obliterated the large Roman cities of Pompei and Herculaneum or the 1902 eruption of Mount Pelée on Martinique, that completely destroyed the town of St Pierre, leaving only two survivors out of a population of some 22,000, served to reinforce the message. With human populations world-wide soaring, it is inevitable that humans will settle closer to potentially active volcanoes in ever-increasing densities. As a result, more human beings than ever are at risk from volcanic eruptions.

With this in mind, the HYPERLINK “http://en.wikipedia.org/wiki/International_Association_of_Volcanology_and_Chemistry_of_the_Earth%27s_Interior” \o “International Association of Volcanology and Chemistry of the Earth’s Interior”  (IAVCEI) set out to identify volcanoes that had a history of large, potentially destructive eruptions and were located close to high-density populations. As the project was initiated as part of the United Nations-sponsored International Decade for Natural Disaster Reduction, hence the name Decade Volcano, it was hoped that the United Nations would fund the programme the aims of which was to identify the major strengths and weaknesses of current hazard management and contingency plans at each volcano, and how to address the weaknesses identified.

Fig. 2 The UN General Assembly. It was ultimately here support for the Decade Volcano programme must be obtained, not at some faculty. (Marty Lederhandler, Associated Press)

It must be realised that in a highly politicised world, decisions are rarely based on scientific grounds, but on what is politically feasible. Hence the volcanoes chosen had to have a broad appeal, geopolitical as well as demographic, to the representative body that was to grant the funding. But in order to achieve at least a semblance to a scientifically motivated choice, the volcanoes chosen had to threaten tens of thousands of people with at least two of the following volcanic hazards – lava dome collapse, pyroclastic flows, lava flows, lahars, tephra fall or volcanic edifice instability. Furthermore, the volcano had to have been recently geologically active. As a sop to the UN representatives, who in turn would have to have the sanction of their masters at home, any volcano chosen had to be politically and physically accessible for study and there must also be local support for the work.

In the end, the UN did not undertake to support the programme, and funding had to be obtained elsewhere. Where there is a national body responsible for volcanologic research and monitoring such as in the USA, Italy, Mexico or Colombia, this organisation has assumed responsibility for the volcano or volcanoes that naturally fall under their aegis. The European Union supports research and monitoring at European volcanoes whereas some of its member countries, France and Germany, have undertaken to support the work of Indonesian authorities at the same time giving French and German volcanologists access to research at active volcanoes.

Fig. 3 Koryaksky volcano overlooking Petropavlovsk’s 180,000 inhabitants (Wikimedia)

The 16 volcanoes given status as Decade Volcanoes, with the (main) human habitations threatened given in brackets, are:

USA – Mount Rainier (Seattle, Washington) and Mauna Loa (Hawaii)
Japan – Sakurajima in the Aira caldera (Kagoshima and Kirishima) and Unsen (Unsen and Nagasaki)
Russia – Avachinsky and Koryaksky (Petropavlovsk, Kamchatka)
Italy – Vesuvius (Naples) and Etna (Catania)
Greece – Santorini, a.k.a. Thera (Aegean Islands)
Spain – Teide (Canaries, holiday paradise of Europe)
Mexico – Colima (Colima, Manzanillo)
Colombia – Galeras (Pasto)
Phillipines – Taal (Manilla)
Guatemala – Santa Maria/Santiaguito (Quezaltenango)
Indonesia, Java – Merapi (Yogyakarta)
Democratic Republic of Congo – Nyiragongo (Goma)
Papau New Guinea – Ulawun (???)

While no one doubts that given a possible or hypothetical worst-case scenario, these volcanoes pose a serious threat to nearby human settlements, it’s quite obvious that politics has been a main factor in their selection as Decade Volcanoes. The financially and politically influential USA, Russia and Japan have each been assigned two with four to the equally politically and economically influential Europe, while the large Hispanic contingent of nations accounts for no less than five of the sixteen.

Nevertheless, it is a start and a good one too. The programme has led to a better understanding of the volcanic hazards and in one case, at Etna in 1992, measures were taken on the advice of IAVCEI (International Association of Volcanology and Chemistry of the Earth’s Interior) that eventually prevented a lava flow from reaching a town. Scientists and civil protection authorities have learnt to cooperate as with the very nasty eruption of Merapi in 2010, without which the death toll would undoubtedly have been much higher. Awareness of volcanic hazards from volcanoes not on the list has been heightened as well. A summary of the advances and achievements brought by the first ten years of the programme can be found at “http://www.sveurop.org/gb/articles/articles/decade.htm”  Directly below, followers of this blog may be surprised, or not as the case may be, to learn that our old friend Nemesio M. Pérez compiled the final report of the IAVCEI meeting in Teneriffe, 2010.

Fig. 4 The 2334 m high Ulawun stratovolcano, Papau New Guinea (listspress)

But it cannot be claimed that all the Decade Volcanoes represent the 16 volcanic centers most dangerous to human populations, nor that the efforts are directed where they are most needed. Let us look at Ulawun, Papau New Guinea as one example! Ulawun, a 2334 meter high stratovolcano, is the tallest volcano of the Bismarck Archipelago chain and one of the most active volcanoes in Papua New Guinea. According to John Seach, it is composed of lava flows interbedded with tephra and erupts basalt and andesite through Strombolian and Pelean eruptions. Thus the main danger to humans comes from the pyroclastic flows associated with Pelean eruptions, the other Decade criteria met are those of tephra fall and structural failure. John Seach reports that the 1980 eruption resulted in an 18 km high eruption column that devastated some 20 square kilometres and claims that structural collapse could potentially lay waste to an area hundreds of square kilometres. That is an area with a radius of about eight to ten kilometres.

But is Ulawun really such a highly dangerous volcano? First of all, as far as I can tell from maps and satellite images, there are few human habitations within the danger zone. Second, it erupts basalt and andesite, neither of which are associated with particularly devastating eruptions. Basalts erupt effusively as at Hawaii or semi-explosively as at Etna. Andesites predominantly erupt explosively, but rarely result in a high VEI as both volume-wise and explositivity-wise they are small to medium. Third, Ulawun erupts regularly, 34 eruptions over the past hundred years with most assigned a VEI of 1, 2 or 3 with a single VEI 4. While this is impressive and a constant reminder to the locals that theirs is a dangerous volcano, the regular eruptions prevent the build-up of a much larger eruption – and also inhibits the build-up of a large human population on its fertile slopes.
Let’s now move our examining eye some 200 km to the NW of Ulawun! There we find Rabaul, the city of WW II fame fought over by the Japanese and Americans for its superb anchorages. Up until 1994, Rabaul was the provincial capital with a population of some 17,000 inhabitants. On September 19th 1994, the Tavurvur and Vulcan stratovolcanoes erupted simultaneously which destroyed the town as had happened previously in 1937. Fortunately, no more than five people were killed this time against 500 on the previous occasion. Today, the provincial capital has moved to Kokopo, a scant 20 km away, but Rabaul is slowly being rebuilt as happened after its 1937 destruction.

Why is Rabaul then, to borrow a phrase from Carl, such an ill-begotten piece of real estate? The reason for its superb anchorage is that it is a submerged caldera, 8 by 14 km wide. The town is located on the rim of the caldera and there are no less than eight vents of which four are stratovolcanoes such as the already named Tavurvur and Vulcan. Just to make certain of the town’s eventual destruction, the spit of land on which Rabaul is situated is not only the edge of the Rabaul caldera. A scant three kilometres due north lies the equally submerged Tavui caldera, source of the 5100 BC Raluan rhyolitic ignimbrite, an eruption listed as producing 4.0  ±  1.0  x  109 m3 of tephra.

Fig. 6 Map of the Rabaul Caldera (USGS)

No doubt there are other, and better examples of volcanoes that ought to have been Decade Volcanoes instead of some of the obviously less than well-chosen current ones, but it cannot be denied that the project has realised its goals and done so very well indeed! The context of its genesis, well before the advent of the world-wide web with its instantly accessible webcams and monitoring equipment, has to be taken into account as well. In the final analysis, the Decade Volcano programme has to be regarded as being highly successful.

HENRIK

Suggested reading:

HYPERLINKS :

http://upload.wikimedia.org/wikipedia/commons/4/42/WikiReader_Decade_Volcanoes.pdf

http://www.iavcei.org/” http://www.iavcei.org/

http://www.sveurop.org/gb/articles/articles/decade.htm

http://www.geo.mtu.edu/volcanoes/rabaul/rabaul.usgs.html

The pain filled issue with Ischia

Photograph by Giovanni Mattera. Castle Aragonese seen from Ischia. The castle is sitting ontop of a resurgent dome plug from a flanking vent.

The World’s most ill begotten piece of real estate – Part III

The Chinese have a saying, “May you live in interesting times”. And it is in no way a friendly thing to say; on the contrary it is a rather magnificent curse. In Naples people live all their lives in interesting times. If it was not enough with being the poorest city in Italy, they also have to contend with the Camorra (local mafia), drug-wars, corrupt politicians, strikes and general civil unrest. To top it off even further they have built their city on top, or around, no less than 3 active super volcanoes. Could the times get more interesting than that? Well you could add large earthquakes and tsunamis to the list.

Ischia, or more correctly Monte Epomeo, started it’s activity about 350 000 years ago. Technically it is of the complex volcano type. During the first 300 000 years it grew and developed a large edifice paired with an over-sized volcanic sub-structure.

56 000 years ago the volcano had reached the critical level where the edifice was too large and heavy to be sustained on top of the very large magma chamber. The eruption probably started as a very large VEI-6 eruption that emptied out the magma chamber sufficiently for the roof to collapse. And since Ischia is an Island it then got messy as the ocean roared down into the open magma chamber. The ensuing VEI-7 explosion created the Green Tuff Ignimbrite. This Green Tuff Ignimbrite should not be confused with the even larger Pantelleria Green Tuff (Italy is rather interesting…) that covers most of the Mediterranean area.

Photograph showing Sant Angelo D’Ischia, another resurgent dome from a flanking vent.

After the eruption the Island was completely gone. As far as is known a 23 000 year long period of dormancy followed, but there might have been minor subsurface eruptions that helped to start healing the roof of the volcanic chamber system.

33 000 (Ar/K-dating) years ago a new phase started where the volcano had frequent effusive eruptions that helped to weld the tuff together healing the roof of the magma chamber along the entire 10 kilometer wide caldera.

28 000 years ago things started to get really interesting. By then the roof above the chamber was sufficiently structurally sound to hold for the increasing pressure inside the chamber. That caused the entire roof to be pushed upwards.

Most of the readers in here are familiar with the concept of resurgent lava domes. We have all seen them being pushed out of craters like odd plugs. For those interested in seeing the phenomenon I recommend Soufriere Hills at Montserrat. Thing is though that it is normally smaller craters that suffer from this rather dangerous condition.

The island of Ischia photographed from Castle Aragonese. The mountain area in the background on the island is Monte Epomeo, a resurgent dome formed as the caldera floor is lifted up above the caldera rim. Here be Dragons.

Problem here is that Monte Epomeo is a super volcano, and as such does things in super-size. And if you super-size a resurgent dome, then you have an entire caldera floor rising upwards. Just imagine the pressure needed to push up a ten kilometer wide plug 900 meters in 28 000 years.

I know, we are only talking about 3.2 millimeters per year on average, but it still requires rather stunning amounts of power. The uplift is though larger than that, the reason for that being failures in the resurgent dome with rock-slides and sector failures of the dome as it started to stick up above the caldera rim. 5 600 years ago the dome passed the rim. During the push up phase the dome had also dragged the caldera rim with it above surface, and around the island an elevated area has been created by the pressure. So, a lot of pressure has gone also into moving parts that technically are not a part of the resurgent dome.

Eruptive and other behaviors

The most common type of eruption at Ischia is smaller eruptions taking place between the resurgent dome and the caldera rim. There are quite literally hundreds of fissures, cones, and other volcanic vent types encircling the dome. These eruptions normally follow episodes of rapid surging (uplift) of the dome.

There are two more dangers on top of the island caused by the resurgent dome. The first one is quite simply sector collapses, landslides and rock-falls as the brittle welded tuff suffers structural failure. Some of these slides and rock-falls have reached as far as the coast line.

General volcanic map of Ischia showing major features of the volcano. Click for larger image.

The more dangerous version of failure is the lateral flank eruption. That happens as magma pushes upwards and builds up tremendous pressure and swelling of the side of the dome and the side of the caldera rim. Think Mount Saint Helens here and you get the picture. This causes a large pyroclastic flow going laterally over the island until it reaches the coast, then it will continue over the water. If it happens in the wrong direction it will hit inhabited land.

Critical lateral collapse of the resurgent dome towards the Bay of Naples.

During the last 12 000 years there has also been 3 sub-surface collapses of the island causing massive debris flows running out into the Tyrrhenian Sea. And there are several spots along the coast line where parts of the Island have calved off into the ocean. When this happens large tsunamis will race into the Bay of Naples destroying any part not high up. The latest known widespread tsunami in the area is known to have happened 800BC according to written records.

Debris flow from a sub surface failure of the shelf around the island. The surge direction caused a large tsunami to go into the Bay of Naples.

In the end though it is probably the super part of Monte Epomeo that interests people more than anything else. Because however you look at it, there is between 70 and 210 cubic kilometers (conservative estimate) of magma in various grades of fractionalization down under that ever uplifting plug. The volcano also has an ample supply of fresh water to drive up the pressure for a larger eruption, and when that happens the same thing that happened to Krakatoa and Santorini will happen to Ischia. And as with the two more famous volcanoes, it has happened before.

Current status of Ischia

Even though Ischia is currently not showing any sign of erupting other than the steady uplift she is deemed by INGVs Director Guido Bertolaso to be the most likely volcano to erupt due to the rapid buildup of magma that they have recorded. Bertolaso even went so far as stating “if I had to say which is the volcano with the most loaded gun barrel, I’d say it’s not Vesuvius but the island of Ischia”. He though went on to state that no eruption is imminent. This becomes evident if one looks at the lack of heightened volcanic tremor, and minimal amount of magmatic earthquakes.

Risks of Ischia

The risks are roughly discussed below in the order of likelihood. Ischia is the volcano most likely to have a large eruption in the Naples area. One should though remember that it is most likely to have a normal VEI-1 to VEI-4 eruption when it erupts next. This would mainly affect the 60 000 residents on the island, and the same amount of tourists.

Rock falls, dome failures and landslides from Monte Epomeo is also fairly likely to happen in the foreseeable future due to the resurgent dome uplifting. This will also only affect the local residents and tourists.

Large landslides either at the coast, or out on the elevated shelf that surround the island is fairly likely to happen within the next few thousand years as the pressure building up raises the land up and weakens the structure of the flanks. When this happen large tsunami waves will hit the Bay of Naples causing widespread destruction. This is also the risk that is hardest to predict and mitigate.

In the same timeframe there could be another partial dome collapse causing a Mount Saint Helens style eruption. This would destroy all buildings on the island, cook the inhabitants, and depending on the direction of the pyroclastic surge hit areas far into the Bay of Naples. I do not think we need to contemplate the effects of a hydro-magmatic eruption at the VEI-7 scale. I would only like to point out that Ischia is the most likely candidate of having such an eruption in the neighbourhood of Naples. Right now there is nothing pointing towards it happening within the next millennia, but in the end it is likely to happen within the next ten millennia due to catastrophic failure in the resurgent dome.

Ischia early in the morning. The sleeping Dragon rests calmly.

Ischia is more likely to kill people than any other volcano. This is due to the absolute lack of places to run to quickly since it is a heavily populated island, and that half of the inhabitants at any given time are tourists not knowing where to go. So even the smallest event will get messy, best case scenario is probably a VEI-1 eruption with clear precursors for INGV to order a complete evacuation. Anyhow, anything interesting happening at Ischia is more likely to kill thousands up to millions than any of it’s siblings due to it having more modes of operation.

Not only do we live in interesting times, now we have an inflamed Ischia.

Short addendum on the Turkish quake

There has been an earthquake just south Antalya. It ranged between 5.8 and 6.2, figures are going to be revised. The distance from Antalya, and depth is very likely to cause damages to houses and fatalities.

The associated beach ball has a rather odd look to it. But this is also likely to change. The EMSC-CSEM site has gone down due to pressure from people trying to get info. USGS is open for business. Here is a link to their beach ball and other technical data.

http://earthquake.usgs.gov/earthquakes/eqarchives/fm/neic_b000ac4h_fmt.php

Oddball beach ball of Turkey.

CARL

Monte Somma & Vesuvius

Painters rendition of the 79 AD Pompeian eruption of Vesuvius.

The World’s most ill-begotten real estate, Part II

Monte Somma is an old volcano, activity started 400 000 years ago. Over the next 375 000 years a massive strato-volcano was built up at around the same location as todays Vesuvius. The main geological component is guarinite, an epitaxy of hiortdahlite, wöhlerite and låvenite. There is no known record of any caldera forming events during this long period. At the end of the period Monte Somma had an edifice containing four times the rock volume of today’s Vesuvius (calculated conservatively).

The volcanicity in the area is driven by the back-arc subduction zone caused as the African plate slams into the Eurasian plate, and then being pushed under. On the European side melt from the friction of the plates is being released through the Campanian volcanic arc. Other close by members of the volcanic arc is Campi Flegrei and Mount Epomeo (Island of Ischia).

25 000 years ago Monte Somma suffered the Codolan eruption, an ultra-plinian eruption that eradicated almost the entire volcano in a cataclysmic failure of the magmatic chamber. The Codolan ash lies on top of the Campanian Ignimbrite caused by Campi Flegrei 34 000 years ago, making the Codolan eruption the youngest of the cataclysmic events caused by the Campanian arc. The highest remaining point after the eruption is today known as Punta del Nasone (Tip of the Nose), an 1 132 meter high edifice on the caldera rim. The eruption probably had a significant effect on the population size in southern Europe.

Google Earth Image of Vesuvius. On the upper left you can clearly see the caldera wall of Monte Somma with the Tip of the Nose (1132m).

Vesuvius is born

From the ashes of Monte Somma a new volcano started to grow almost immediately. During the first 8 000 years the new volcano had a fairly unevolved magmatic chamber system. As such it could not cause large eruptions, instead it slowly, but steadily built up.

That changed about 17 000 years ago when a cycle started consisting of frequent small to medium eruptions interspersed by Plinian eruption ranging between VEI-5 and VEI-6. To date there has been 8 of these larger events in the current cycle. Calling them large might seem ridiculous compared to the Codolan ultra-plinian event, but one should compare within the cycle. These eruptions are believed to range between 5 and 15 cubic kilometers of ash counted in Dense Rock Equivalent (DRE). Compared to the 0.25 cubic kilometers (DRE) of Eyjafjallajökull these eruptions are rather large.

These larger eruptions take place roughly every 2 000 to 3 000 years. This time interval makes sense if one takes into account that the magmas needs time to fractionalize enough to evolve to the highly explosive magmas involved in these eruptions.

The latest plinian eruption was of course the 79 AD eruptions that eradicated the cities of Herculaneum and Pompeii. I will cover this eruption in a separate article in the series about Neapolitanean volcanicity. This eruption is the reason we call these eruptions plinian. The reason for that being the historian Pliny the Younger (Plinius), writing down the quintessential record of the eruption.

The plinian eruption before that was the Avellino eruption (Pomici d´Avellino) that took place 3 800 years ago. Archaeologists have noticed that this eruption had a large effect on the regional Bronze Age population.

After the 79 AD eruption Vesuvius has had numerous small to medium sized eruptions ranging from VEI-1 up to VEI-5. Some of these have been notoriously ashy. The 472 and 1631 eruptions yielded ash that travelled as far as Constantinople.

Vesuvius today is rapidly getting known as the Garbage Dump of Italy. This is due to a large amount of both legal and illegal dumping of garbage and industrial waste in old flanking vents and cones. This has raised the toxicity around the volcano to a level where one should not eat anything growing on or around the volcano. Even the fabled wines of Vesuvius are now deemed not fit for human consumption. It is sad that Man’s folly is destroying one of the world’s most beautiful vistas.

Technically Vesuvius is a somma-volcano, a type of volcanoes named after its parent volcano. The term refers to a fully developed strato-volcano that has formed inside a caldera of an older destroyed strato-volcano.

Photograph by the US Air Force. Eruption of Vesuvius 1944 taken from a bomber plane.

Risks of Vesuvius

Vesuvius can theoretically have 3 types of eruptions if we look historically. These are in order of threat-level the regular eruptions, the plinian eruptions, and a possible recurring ultra-plinian Somman event. Let us look at them one at a time.

Before we go on I would like to say that the projected death tolls for the respective eruption sizes are from figures that have been calculated by INGV, The Italian Government, The regional government of Naples, independent catastrophe mitigation experts, EU and the UN Decade Volcano Program.

The lower end figure is the best possible figures. Basically it would require functioning scientific volcano predictions, and a high-powered highly ordered Government ruthlessly enforcing evacuations and other protective measures. Basically we are talking about northern European style Government with heavy military aid here. The high figure is based on INGV being disregarded for political reasons, week or no mitigative measures taken, lack of functioning roads being accounted for, and the general nonchalant attitude in the region. I would here say that INGV will do their work; they are highly capable and very diligent in performing their duties. I just hope that they will be allowed to do it by the highly corrupt Neapolitan local politicians.

The risk is of course heightened by the high population numbers, and that people live close to, or even on the flanks of Vesuvius.

Central crater of Vesuvius.

Normal Vesuvian eruption

Vesuvius is a highly prolific volcano, and it is known to have had several instances of magmatic intrusion since the 1944 eruption. The last major intrusive episode was taking place between 1996 and 1999. So far this is the largest of the intrusive events post 1944.

It is highly likely that Vesuvius will have an eruption during this century. When it happens it will almost certainly be in the range of VEI-2 to VEI-4. One should though note that there have been two out-layer small VEI-5 eruptions since the 79 AD eruption and also that there has been a few VEI-1 eruptions. Median eruption (most likely) would be a VEI-3 size. Ash, volcanic bombs and pyroclastic flows would be the largest risk for the population.

Death rate would be between 0 and 100 000 depending on size of the eruption, and the amount of protective measures taken.

Vesuvius in the background photographed from Herculaneum.

Plinian Vesuvian eruption

Vesuvius is from a short geological time-frame ranging in on a plinian eruption. Nothing points towards that the eruptive cycle that started 17 000 years ago has changed to the better. Judging by previous behavior the next plinian eruption will occur during the coming millennium.

The risk of a plinian eruption is driven by the rate of fractionalization of the magmas. Normally this type of explosive eruptive behavior requires the volcano to not erupt for a few centuries before the plinian eruption, thusly giving the magma time to evolve as intrusions bring in new material that mixes with older colder magmas to revigorate the explosivity until the volcano quite literally explodes. This seems to not be the case with Vesuvius. One suggestion might be that there are different magma chambers that are responsible for the larger eruptions and small shallow chamber responsible for the smaller eruptions. Be that as it may, do not expect a long period of repose between a normal eruption and a plinian. Risks for a plinian eruption would be large amounts of ash, large pyroclastic floods, and lava bombs ejected up towards 40 kilometers. There is also risk of tsunamis causing additional deaths in the low laying parts of the Bay of Naples. Larger pyroclastic flows can rush over the water’s surface and hit areas that are not close.

Death rate between 10 000 and 1 000 000 depending on prevailing wind and the amount of people evacuated.

Photograph from Whiteynet. Vesuvius encircled by Monte Somma caldera.

Ultra-plinian eruption

This option is highly unlikely in the foreseeable future. Why? Compared to the size of the Monte Somma edifice we know what the maximum size the volcano can grow to before it suffers a catastrophic fail. Even if we count in the secondary caldera formation normally are smaller than the first one due to damages to the crust we still known that it will take quite some time to build the volcano up sufficiently both above ground and below ground.

If we calculate the growth rate of Vesuvius and compare it with the size of Monte Somma before the caldera event we see that it will take a minimum of another 75 000 to 100 000 years to grow to comparable size. Statistically we know that secondary caldera formations are 50 to 75 percent of the original event size. So, we are most likely looking at something in between 25 000 to 75 000 years of continuous growth before we need to worry about it.

The major risk of an ultra-plinian eruption would be ash covering a very large area, the explosions involved would instantly crush anyone within 25 kilometer. Think a hydrogen nuclear bomb shock-wave here. Between 25 and 50 kilometers there would be an initial 50 percent mortality rate due to high aerial ash content, lava bombs, and enormous pyroclastic flows covering large parts of the Bay of Naples. After the event pretty much no buildings within the 50km radius would be left standing up. Nationally deaths would occur due to ash and gas contamination. The coming year southern Europe would suffer crop failures. There will be an increased likelihood of hemispheric rapid cooling causing additional deaths and famine.

Death rate, 100 000 to 4 000 000. Supervolcano as a term is nuisance, but if one would erupt in a population the size of Naples it would have major impact. Regardless of the term, the effect on the population of southern Europe would be truly “super”. Remember, it is highly unlikely to happen.

This was the second installment in a series that will be five posts long. Remaining are the two other supervolcanoes encircling Naples, and of course the mentioned Pompeian eruption.

CARL

The world’s most ill-begotten piece of real estate

Gulf of Naples (Campi Flegrei Caldera) with Vesuvius in the background.

Few cities on the planet can even start to compete with Naples in being ominously placed from a geological standpoint. The city has not only a tremendous historical background; it is also totally surrounded with active super volcanoes.

A few years ago I had the pleasure of having dinner in a villa on the slopes of Monte Vesuvius together with Italy’s car tycoon numero uno. After a tasty dinner together with nice wines we were sitting looking out at the ocean drinking a ridiculously old grappa (grappa tastes like a rotting hamster-cage smells) and I just had to ask if he never where worried about having a villa on one of the worlds more famous volcanoes. The answer was rather Italian; He turned around, raised all five fingers into the air in the general direction of Vesuvius and uttered the Italian immortal phrase “va’fan’culo”. I interpreted it as “who cares”. Actually it is a bit stronger than that in translation.

Vesuvius residing within the Monte Somma Caldera.

But in a way it summed up the Neapolitan view on their 3 troublesome super volcanoes. To hell with them. Basically this opinion explains why the citizens even do their best to impede scientific work on their volcanoes. In 2010 the mayor of Naples stopped drilling into Campi Flegrei to increase the monitoring of the volcano.

Naples has more than 4 million inhabitants in the greater Naples urban area; at least 1 million of them are directly threatened by the 3 giants under them. In theory there is a plan to evacuate the citizens, but 3 factors would most likely hamper any evacuation.

Image by NASA. Campi Flegrei seen from space.

The first one is of course the issue with the “va’fan’culo” attitude against their volcanoes. Most likely many would not heed an evacuation order in time. The second issue showed itself during the Campi Flegrei inflation periods of 1970 and 1984 to 1985. Back then inflation pushed Pozzuoli up more than 3.3 meters, and still only an area of 10 city blocks was evacuated. This points to it being likely that political pressure would impede any scientific call for evacuation before it was too late. The third reason is quite simply the poor state of the road network in and out of Naples. There is just no way to evacuate 1 million people in the stipulated 3 days. An amount of time that could well be quite less after the usual Italian political infighting.

Not even mighty ancient castle walls are protection for Naples.

This was the first part out of a 4 piece special. In the next 3 I will go through all 3 super-volcanoes in turn. Since all 3 of them are so different, and pose so different types of risks they deserve at least one post each.

Now you are most likely going, where did he find a third super volcano? Well, that will become clear in the next post.

CARL