The Earth is peppered with volcanoes, and for the most part, they aren’t dangerous. Some, however, certainly are, ranging from the known city-destroyers like Vesuvius to the civilization-enders, like Santorini. In order to raise awareness of the most dangerous volcanoes in the world, an online collaboration between the University of Manchester and volcano enthusiasts has produced a list of the top ten most dangerous volcanoes – those that are likely to erupt in the next 100 years and cause up to 1 million deaths each.

The top three most dangerous volcanoes are, according to the list, Iwo Jima in Japan, Apoyeque in Nicaragua, and Campi Flegrei, Italy. Their hazard potential was based on their proximity to large human populations and how destructive their eruptions could be based on their current activity and eruption history.

This isn’t the first time a list like this has been composed. The Decade Volcanoes, a previous top 16 list, was put together by the International Association of Volcanology and the Chemistry of the Earth’s Interior (IAVCEI). Essentially, if a volcano had a history of major, destructive eruptions, and they were presently located very near to large, densely-packed human populations, then chances are it’s on this list. It’s quite different from the University of Manchester-approved one; only one volcano makes both lists (Taal, in the Philippines).

Yellowstone caldera – infamously a “supervolcano,” a certain harbinger of global devastation – isn’t on either list. It appears to erupt every 650,000 years or so; this means it is due in the next 10,000 years, long after these listed volcanoes are likely to experience a major eruption.

However, the Decade Volcanoes list is nearly twenty years old, and a huge amount of new scientific data has been published since then; in addition, our understanding of volcanology has advanced greatly. Professor Albert Zijlstra, an astrophysicist at the University of Manchester, explained to IFLScience the motivation behind his contribution: “This is a list that hopes to improve public awareness of volcanoes whose dangers have not been recognized. They are all poorly monitored, or the monitoring data is not being made publically available. Iwo Jima, for example, is a military site.” The Decade Volcanoes are, for the most part, heavily monitored.

^{Image credit: Volcanoes are often monitored from space these days. NASA Goddard Space Flight Center/Flickr; CC BY 2.0}

By creating the new list, the authors hope to raise awareness of those that are certainly very dangerous but aren’t often recognized to be so. “Mount Cameroon only has one guy monitoring it – and his equipment keeps getting stolen,” Zijlstra added. “Mount Rainier in the U.S. is on the Decade list, and it’s incredibly dangerous – but it’s so well-known and monitored, so there was nothing to gain by adding it to our list.”

This top ten, the ordering of which is subjective, was based on a plethora of data made available over the last 20 years, and will highlight dangerous volcanoes around the world that have, until now, remained largely unknown to the public. However, Prof. Bill McGuire, renowned volcanologist and professor of geophysical and climate hazards at University College London, is unconvinced. “Trying to predict when then next big one will erupt is impossible,” he told IFLScience. “Any such list is educated guesswork. The biggest eruptions in the last 200 years or so were from relatively obscure volcanoes.

“Vesuvius is not on the list, which is very strange. It's definitely overdue for an eruption, and half a million people live within the danger zone. In contrast to this, Campi Flegrei is, which is one of the most heavily monitored volcanoes in the world.

“It seems strange that they didn't involve a volcanologist when putting this list together,” McGuire concluded.

The full top ten are as follows:

1 - Iwo Jima, Japan

2 - Apoyeque, Nicaragua

3 - Campi Flegrei, Italy

4 - Mount Aso, Japan

5 - Trans Mexico Volcanic Belt, Mexico

6 - Gunung Agung, Indonesia

7 - Mount Cameroon, Cameroon

8 - Taal, Philippines

9 - Mayon, Philippines

10 - Gunung Kelud, Indonesia