It has taken a long time, far longer than originally intended, to bring the New Decade Volcano Program to a successful conclusion. Indeed, there was a point during the summer at which it seemed that it would be left unfinished as after writing two of the first four articles Carl found himself in a position where first other commitments, then ill health curtailed his participation. Thanks to the help of Albert in particular, the series is soon to be concluded and our choice for Number 1 revealed. But ahead of next week, now is a good time to recapitulate what has gone on before.
The NDVP is not an official list in any way as the only organisation with the authority to officially propose such a list is the IAVCEI, the International Association of Volcanology and Chemistry of the Earth’s Interior. It is the IAVCEI that decides if there will be a new Decade Volcano Program, and if so which volcanoes will be included. Our NDVP list is nothing more than a suggestion that a) there should be a new programme, and b) the criteria that should guide the choice of the ten most dangerous volcanic systems that should be prioritized. Even if a volcano that is well studied, well monitored and where adequate hazard mitigation and contingency plans are in place can still be dangerous, such a volcano is nowhere near as great a threat as one that is not well studied, not well monitored or even not monitored at all and where there are no adequate hazard mitigation and contingency plans. Such volcanoes located in or close to densely populated areas were our primary targets and our choice of the 1 MDE-criterion, “One Million Death Expectancy”, was our way to draw attention to the fact that there are such volcanic systems, plenty of them.
10. Kelut, Indonesia
Gunung Kelud is already one of the deadliest volcanoes in history with a confirmed death toll that has surpassed 10 000 dead, with half of those during a single eruption. The modes of lethality include pyroclastic flows, lahars, volcanic ash and widespread scattering of volcanic debris. Due to the form of its eruptions and way of operation it is likely to also be able to produce pyroclastic base surges and caldera forming events. Although this volcano is relatively well studied and monitored, the way the volcano works needs to be better understood since it is the archetype of its own class of volcanoes, artesian crater lake volcanoes. This type of volcanoes are among the deadliest known to mankind.
9. Mayon, Philippines
Mayon is widely regarded as one of the most beautiful and perfect volcanic edifices. Unfortunately, there are several risk factors involved with such a huge edifice. The greatest and most immediate one of these being a flank collapse initiated by either a large tectonic earthquake or a volcanic eruption. Recent research has shown that the volcanic edifice is built on or near two major faults and there are incipient cracks on several of its flanks. The main problem with Mayon is that while it is relatively well-monitored it is far from adequately studied.
8. Taal, Philippines
Like Mayon, Taal is relatively well-monitored but is far from adequately studied. Because it has such a small volcanic edifice, it is actually marketed on being the World’s smallest volcano, located in the middle of a scenic lake it is easy to miss that this lake is a huge caldera, 25-30 km in extent, that the volcano is capable of large VEI 6 eruptions and that Manilla, some 50 km away, is actually in part built upon the ignimbrites produced by several of these eruptions.
7. Mt Cameroon/Mt Fako, Cameroon
Few volcanoes on the planet represent such an awesome sight as the majestic Mount Cameroon. It stretches from the edge of the Atlantic at Bakingili Beach and reaches an astounding height of 4040 meters. It is located in what is known as the Cameroon Volcanic Line, a volcanic zone that includes several major volcanic centres and explosive calderas. Yet so little is known about it that even what drives the volcanism remains unknown. Monitoring of Mt Cameroon is a secondary task of the Park Rangers whose monitoring equipment is limited to the Mk1 Eyeball and telephone landlines that are regularly scavenged for their copper content.
The Sunda Arc is home to two of the three largest volcanic eruptions of the past 1,000 years; Rinjani (c. 1257 CE) and Tambora (1815 CE). It is also the location of the tourist paradise of Bali, but within 50 km of the tourist areas lie two medium-sized calderas; Bratan and Batur, and a gigantic stratovolcano, Mt Agung. While the easily accessible Batur caldera has been the subject of several studies, the less easily accessible Gunung Agung and in particular Bratan with several young volcanic edifices as great as or larger than Vesuvius remain virtually unstudied.
5. Mexico City and the Trans-Mexico Volcanic Belt
The TMVB represents an unusual geological setting where three continental fragments are or were being subducted, resulting in a marked kink, 45 degrees or more, in the Central American subduction arc. The resulting volcanism is unusual too in that it is perpendicular to the subduction arc and has forged its way through the thickest part of the continental crust, up to 55 km in thickness. Even if an ancient, at least two million years old volcanic arc can be traced along the entire northern part of the TMVB, something unusual has happened here and with one of the greatest metropolitan areas of the world lying slap-bang in the middle, further study is imperative.
4. Aso, Japan
Right in the middle of Kyushu lies the 18 x 25 km Aso Caldera which has been formed by four large, ignimbrite-emplacing explosive eruptions over the past 300,000 years dated at 270, 140, 120 and 90 thousand years ago. Recent studies indicate that just below the crust, at the top of the Astenosphere, lies a large, serpentinised wedge. The copious amounts of water locked up in serpentinites will be released as this wedge melts and large amounts of superheated water can both melt overlying rock to form large quantities of evolved magmas as well as drive very large, explosive eruptions.
3. Campi Flegrei, Italy
While most people believe that Vesuvius poses the greatest risk to Naples, Campi Flegrei, “The Burning Fields”, poses a far greater danger. Not because it is a caldera volcano capable of VEI 7 eruptions, but because much of the Greater Naples area is built within the caldera where even a smaller eruption, by the standards of calderae, can prove a mega-killer. We know from both Campi Flegrei itself and from the similar Rabaul Caldera that the onset of such eruptions can be so rapid as to offset even the best monitoring and hazard mitigation schemes. Since the most recent full-scale caldera eruption ~14,900 years ago, there have been at least a further 65 eruptions of the Campi Flegrei.
2. Apoyeque, Nicaragua
Although Managua, capital of Nicaragua, lies uncomfortably close to two recent caldera-producing volcanic systems, Apoyo and Masaya, a far greater danger is posed by the Nejapa Volcanic Field on its Western city margin which runs all the way to the Apoyeque stratovolcano, as chillingly unassuming as Taal in the Philippines. There is evidence for eruptions up to and including VEI 6 and as several eruptions have occurred below the surface of Lake Managua/Xolotlán, there is a very real danger of a future eruption causing a 20+ m high tsunami with the capacity to strike Managua within minutes of the onset.
Now is the time to get in you guess for which volcano is our choice for number 1!