MOST DANGEROUS VOLCANOES: THE ONE TIMERS HAVE THE WORSE REPUTATION

Volcanoes strike fear in the heart of people, although many choose to live under one or very close to one.  The ones that are more ebullient though seem to scare the most people.

Maybe it's the constant reminder, the lava flow, the ash plume.  

But scientists say that the most dangerous volcanoes might be those that do not make their presence felt, the ones that lurk silently in the background and only erupt one in a very long while. 

The latter volcanoes, those who erupt once and remain silent again until the next big event, are called monogenetic volcanoes.  Such volcanoes are very different from frequently erupting volcanoes, such as Mt. Etna and Mount St. Helens.  

A new study of the monogenetic, or single shot, volcanoes finds that they are very complicated to figure out but can give much clearer clues on how a volcano is formed and behaves.  

By sending an electric current through the crater, the scientists can see, or imagine, the volcanic conduit under the summit.  The current's intensity wanes and waxes as it transits through various types of rock layers.  By tracking and plotting the different intensities as the current passes through the rock gives the researchers a pretty good graphic map of the earth below the crater.  

The research also enables scientists to ascertain whether the volcano was built through explosive or effusive (less dangerous) eruptions, or otherwise.  

The monogenetic volcanoes, due to their nature, afford the scientist a quicker way to understand the formation of a volcano.  Even though monogenetic volcanoes are often smaller, they can be much more violent than their more active counterparts.  In New Zealand for example, the capital is built atop a field of 53 monogenetic volcanoes.  New monogenetic eruptions are expected to strike that zone in a few hundred thousand years. 

There are several monogenetic volcanoes in the lower 49.  The Craters of the Moon in Idaho, the Sand Francisco volcanic field in Arizona, and the Three sisters region in Oregon. 


Source : Live Science/ 8.19.13