Many volcanoes erupt globally

All over the world , from Iceland to Italy, active volcanoes are causing concern.

People watch lava flow during a volcanic eruption near Litli Hrutur, southwest of Reykjavik, Iceland on July 10, 2023 - Photo: AFP/GETTY IMAGES

Many volcanoes "explode"

This November, thousands of small earthquakes marked magma (molten rock) rising from deep underground near the Earth's surface, along a 14km-long fissure near Iceland's Svartsengi geothermal power plant.

Molten rock is now close to the surface, creating wide cracks that cut across the small town of Grindavik, Iceland. The ground is still “swollen” and an eruption could occur without warning.

At the same time, Mount Etna in Sicily (Italy) exploded violently, spewing ash down on neighboring towns.

According to Science Focus, 45 other volcanoes around the world are also rumbling, including Mount Mayon and Ta'al in the Philippines, Mount Santa Maria in Guatemala, Mount Nevado del Ruiz in Colombia and Mount Krakatau in Indonesia.

How do these volcanoes work?

At Svartsengi, Iceland, it is possible that magma rising near the surface will not erupt but simply solidify below the surface.

But if it were, it would have the typical Icelandic "style" of volcanoes: very fluid lava would pour out of long cracks in the Earth's surface, sometimes solidifying into spectacular cones.

At Mount Etna (Italy), the recent eruption marked the normal activity of a volcano that always puts on small fireworks shows: spewing lava or sending columns of ash high into the atmosphere.

The remaining volcanoes are relatively inactive, at least for now. They are limited to small explosions, lava eruptions, or the formation of fast-moving streams of hot ash and gas.

Why do many volcanoes erupt at the same time?

Volcanoes erupt when newly created magma in the crust reaches the Earth's surface and either escapes through an open vent, or by breaking through the rock layer above it.

There are about 70 volcanoes erupting worldwide each year. Of these, about 20 erupt every day.

Iceland is estimated to have about 30 volcanoes, and they can erupt from already formed cones or from new cracks in the Earth's surface.

In fact, Iceland—which sits between the North American Plate to the west and the Eurasian Plate to the east—is made entirely of volcanic rock. The plates are moving away from each other at a fairly slow pace, allowing new magma to rise and create eruptions somewhere on the island every few years.

Elsewhere, many currently active volcanoes lie above subduction zones, where one tectonic plate is diving beneath another.

As the subducting plate pushes deeper into the Earth, it begins to melt, releasing magma that feeds the volcanoes above.

Typically, these magmas are stickier and more gas-rich than those that erupt in Iceland. They can cause much larger, more explosive, and more dangerous eruptions.

Fagradalsfjall volcano in Iceland during the 2022 eruption - Photo: thephotohikes.com

In the past, volcanic eruptions have caused a lot of damage. For example, Mount Etna in Italy. Lava eruptions on its low slopes caused significant damage to inhabited areas in 1928, 1971, and 1983.

Back in time, a massive lava eruption in 1669 destroyed much of the Italian coastal city of Catania.

Many volcanoes are now at low levels of activity. However, they have had much larger eruptions in the past, most notably Krakatau in Indonesia, which killed 36,000 people in a massive explosion in 1883.

Then there was Nevado del Ruiz in Colombia, which killed 23,000 people in 1985. And in 1902, Santa Maria in Guatemala caused one of the largest volcanic eruptions of the 20th century, killing an estimated 6,000 people.

Should we worry about volcanoes?
The short answer is not to worry too much, unless you currently live in the Icelandic town of Grindavik.
Scientists fear that a future volcanic eruption here could follow a similar pattern to the Laki volcano in 1783.
At that time, a large amount of lava erupted at Laki, accompanied by a huge amount of toxic gas, forming a toxic cloud that spread at least as far as Europe and eastern North America.
This event polluted the air, causing extreme weather and famine in places as far away as Egypt and perhaps India.
According to GIA MINH – Tuoi Tre online (Title by Hau Giang Newspaper)