Why some volcanoes keep spewing lava – 11/14/2023 – Science

News of volcanic eruptions only make headlines when they are of major proportions and cause disturbances – as in the cases of Etna, Kilauea, Mauna Loa, Merapi, Eyjafjallajökull or Fagradalsfjall –, but at any time during a given year between 50 and 80 new ones can occur eruptions around the world.

Data from the Smithsonian Institution’s Global Volcanism Program (GVP) suggests that, as of June 2023, there have been 48 continuous volcanic eruptions in the world. And a total of 56 volcanoes erupted in the first six months of the year.

Recently, the movement of magma beneath the Earth’s crust triggered hundreds of earthquakes around the city of Grindavik, Iceland. With seismologists warning that the tremors could be a harbinger of a volcanic eruption, authorities ordered the evacuation of almost 4,000 people last Saturday (11).

Scientists are also keeping an eye on Mount Etna in Italy. One of the largest and most active volcanoes in the world, it has been erupting since the end of last year and spewed large amounts of lava on Sunday (12), but appears to have calmed down since then. According to Italian experts, eruptive episodes like this are normal in the volcano’s recent activity and usually cover the surrounding Sicilian cities with ash.

What is a volcano?

According to the United States Geological Survey, “volcanoes are vents where lava, pyroclasts and steam are expelled to the Earth’s surface.”

Volcanoes can be on land and in the ocean. They are partly the result of their own eruptions, but also the general formation of our planet as tectonic plates move.

Mountain ranges such as the Andes, in South America, and the Rocky Mountains, in North America, as well as volcanoes, are formed by the movement and collision of tectonic plates.

There are four main types of volcanoes: cinder cones, composite or stratovolcanoes, shield volcanoes, and calderas.

Its type is determined by how lava from an eruption flows and how that flow affects the volcano and, as a result, how it affects the surrounding environment.

How do volcanoes erupt?

Essentially, it’s a case of magma, or molten rock, beneath the Earth’s surface bubbling, rising and overflowing, like milk boiling in a pan on the stove.

The magma finds its way into the volcano’s vents and is expelled through the earth and atmosphere. When magma erupts from a volcano, it is called lava.

Some of the most active volcanoes are located on the Pacific Ring of Fire. About 90% of all earthquakes occur within the Ring of Fire.

Can scientists predict volcanic eruptions?

Scientists are able to predict volcanic eruptions hours or sometimes several days in advance. This is not the case with earthquakes, which are much more difficult to predict.

Scientists use seismographic data from earthquakes and other tremors because these can be precursors to volcanic eruptions.

Researchers also monitor the ground for signs of deformation that could be caused by the movement of magma. They also take readings of volcanic gas emissions and changes in gravity and magnetic fields.

Most active volcano in Europe

Mount Etna is the most active volcano in Europe and one of the largest in the world. Its recorded volcanic activity dates back to 1500 BC. Since then, it has erupted more than 200 times.

Current eruptions on Etna have caused flight cancellations from nearby Catania airport.

The use of cars and motorcycles was also banned for 48 hours due to the large amount of ash on the roads. Ash can be slippery and increases the risk of accidents.

Other erupting volcanoes

One of the most famous long-term eruptions was that of the Kilauea volcano in Hawaii. Its activity that began in 1983 continued —almost without stopping— for 35 years until 2018, only to return to activity again in 2021. The eruption is still ongoing.

Dukono in Indonesia began erupting in August 1933 and is still continuing. Santa Maria, Guatemala, began erupting in June 1922 and has not stopped.

And Yasur, in Vanuatu, began erupting around 1270 and was still active on June 9, 2023.