Older Volcanoes That Erupt Less Often Produce More Dangerous Explosions, New Research Reveals

The University of Geneva (UNIGE), Switzerland, with the aid of a group of geologists and geophysicists, conducted a scrutiny of literature on volcanic eruptions and concluded that older volcanoes that do not erupt as often could produce more dangerous explosions. Their findings were published in Nature Reviews Earth and Environment.

Can a volcanic eruption be predicted?

Predicting when a volcano will erupt has never been easy for experts. There are several factors that they need to consider in determining when and how volcanoes erupt. One of these is the age of the volcanoes. According to the Daily Mail, the age of a volcano's crater may provide a hint on its eruption.

UNIGE's study provided a few examples to explain this notion.

Mount St. Helens in the USA, which was active 40, 000 years ago, was the first example that they cited. In the year of its last explosion in 2008, Mount St. Helens had small and harmless eruption.

Meanwhile, Indonesia's ancient Mount Toba began exploding over 1 million years ago and last erupted 70,000 years ago, causing catastrophic effects that devastated the surroundings and impacted global climate. It was dubbed as the Toba Catastrophy, "biggest volcanic blast on Earth within the past 2.5 million years."

Also in Indonesia, Mount Tambora, which is a hundred times smaller than Mount Toba, erupted in 1815. Experts thought that Mount Tambora's explosion was the reason behind the country's experience of a whole year without summer in 1816.

UNIGE professor and the study's lead author Luca Caricchi stated, "When a volcano is just starting to be active, its reservoir is rather small and the surrounding crust is relatively cold, which leads to many frequent, but small and rather predictable eruptions."

Old volcanoes have bigger reservoirs and are surrounded by warmer rocks. So when a magma seeps through, the rocks around the reservoir start to deform, preventing it from generating too much pressure, Caricchi added.

The researchers also explained that the assemblage of huge amounts of magma could contribute to larger volcanic eruptions.

Starting the eruptive process with a small reservoir and the outer crust is a bit cold, causing a lot of activity and a small eruption. According to lead author Luca Caricchi of the study, who is a professor at the University of Geneva in Switzerland, cited Today News UK.

When the magma cannot be contained anymore, the volcano will blow its top literally.

It is important to note that knowledge of the age of the volcano, which can be identified by examining the zircon in the rocks, is instrumental in identifying the stage of life of the volcanoes.

Caricchi remarked that about 1,500 volcanoes are active, with 50 ready to erupt per year. This gives an indication of whether a community should move out if there is a chance of a gigantic eruption. It lessens the casualties when a volcanic eruption happens.

Studying the thermo-mechanics of deep volcanic processes and magma going to the surface and how it is composed chemically, scientists conclude that the molten rock from the earth's interior is not what makes a volcano go eruptive.

Meredith Townsend, of the University of Oregon, said that trapped magma in the earthen crust, can stay dormant for millennia and never erupt, noted ScienceAlert. Chances are older volcanoes will have powerful eruptions if the hypothesis holds true.