What are the largest and most dangerous volcanoes?

Answer

That’s hard to say for sure. The most dangerous volcanoes are generally those that are located in densely populated areas, and that have not erupted for a long time, e.g. thousands of years. These volcanoes are considered dormant. The longer the volcano has been inactive, the more likely the next eruption will be a major explosive eruption. An example of this is Pinatubo in the Philippines, which in 1991 experienced one of the largest eruptions we have ever seen. Before the eruption in 1991, Pinatubo was hardly known as a volcano: the surrounding population, and even volcanologists, didn’t really know what this volcano was capable of. If there is a sudden eruption in such a situation, it can have an important impact on the daily lives of the people living in the area. In such a case it is not easy to convince people to evacuate from the dangerous area, because people are not aware of the dangers. Unfortunately, there are still many volcanoes in the world that have been dormant for several thousand years, and of which it is not known what kind of eruptions they are capable of. Many of these volcanoes are located in less developed countries, often in a densely populated area because people depend on the agricultural crops that can grow well on the flanks of the volcanoes.

Then there are also the so-called “super volcanoes”, eg Yellowstone in the United States. We know that exceptionally large eruptions occurred here several hundreds of thousands of years ago and are likely to continue to do so in the future. The problem is that we’ve never seen such a superburst in our modern history, so we’re not very sure what exactly would happen. What we can expect is that at Yellowstone, for example, the entire United States would be covered under a volcanic ash layer, and that air traffic around the world may be disrupted for a long time (weeks, months). In any case, it would have enormous economic consequences.