How could a new island emerge in the Pacific?

An island has emerged in the southwest of the Pacific Ocean due to the eruption of an underwater volcano. A rock formation of this type can disappear within a month or two, or persist for a few more years.

New islands do not appear all the time. But this is not uncommon either: underwater terrestrial activity can cause the emergence of small pieces of land. What results is nothing to do with an island paradise with palm trees and sandy beaches: it is rather a piece of rock.

It is an island of this type that emerged in the heart of the Pacific Ocean, as noted by the Earth Observatory, attached to NASA. In this region, that of Tonga, there is a high density of submarine volcanoes. One of them was triggered on September 10, 2022.

The island is 24,000 square kilometers to date. // Source: NASA Earth Observatory

The image above was captured by the Landsat-9 satellite. You can see very clearly the plume of smoke, which comes from the volcano, which also spat large quantities of ash and lava. This volcanic activity will have been significant enough to lift a piece of earth.

Only 11 hours of eruption will have been enough to bring out the first fruits of the island. At first, it was only 4,000 square kilometers, but in recent days, since September 20, it has blossomed to 24,000 square kilometers. It is still present at the end of September.

The island can disappear anytime

The location where the volcanic event took place is well known to scientists: Home Reef. This is the Tonga-Kermadec subduction zone, where three tectonic plates collide at a contact velocity known to be the fastest in the world — the movement is 24 centimeters per year. The pit formed between the plates is also, in fact, one of the deepest: 10,800 meters. The result is a very long chain of extremely intense underwater volcanoes.

Do not imagine, in any case, being able to put your suitcases on this island: it could disappear without warning. ” Islands created by submarine volcanoes are often short-lived, although they sometimes persist for years “says NASA. An ephemeral island caused by an underwater volcano can persist for only one or two months before being washed away, or for several decades.

In the Home Reef area, four similar volcanic events have already been spotted by mankind. The first two took place in 1852 and then in 1857, forming small temporary islands. By 1984 and 2006 more massive islands had developed, with cliffs up to 70 meters high.

For further

Source: Feuillet et al., Nature Geoscience, 2021

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