World’s newest island rising from undersea volcanic eruption in Japan

Newest addition to Japan’s already impressive list of islands is about 1,000m in diameter and 20m in height

A new island is rising off the coast of Japan due to an underwater volcano eruption.

The new land mass began forming off the coast of the Japanese island Iwoto, about 1,200km south of Tokyo.

The unnamed island is the product of underwater volcanic activity that began on 21 October and is a rare geological phenomenon.

Photos have shown one of the eruptions releasing huge plumes of smoke and debris from the sea.

The Earthquake Research Institute at the University of Tokyo said the island consists of rock masses formed at the eruption site. These could grow larger if eruptions continue.

The new island is part of the Ogasawara island chain. This includes Iwoto, previously called Iwo Jima, which was the scene of fierce battles between American and Japanese forces during the Second World War.

With a series of eruptions continuing for days, volcanic ash and rocks have piled up on the shallow seabed. The island’s tip is also rising above the sea surface.

The newest addition to Japan’s already impressive list of islands is about 1,000m in diameter and 20m in height above the sea, said Yuji Usui, an analyst in the Japan Meteorological Agency’s volcanic division.

In this photo provided by the Japan Maritime Self-Defense Force, steam billows from the waters off Iwoto island, Ogasawara town in the Pacific Ocean (AP)

He said the formation of the new island is a significant development.

The island has already somewhat shrunk, however, because its “crumbly” formation is easily washed away by waves – putting its future existence in doubt.

Fukashi Maeno, an associate professor at Tokyo University’s earthquake research institute, had toured the volcano last month. He said magma had been erupting underwater in a phenomenon called phreatomagmatic eruption.

Such an eruption happens as a result of magma and seawater interacting.

An interaction like this occasionally leads to the spewing of huge rocks and bands of brown pumice stones floating in the sea.

The new island formed by erupted rock (AP)

There are about 1,350 active land-based volcanoes around the world, according to the US Geological Survey.

Researchers have identified thousands of other active “submarine” volcanoes so far. They speculate there to be many more hidden beneath the ocean’s surface – potentially hundreds for each volcano found on land.

A similar island had emerged in 2013 and merged with Nishinoshima, another island in the Ogasawara chain, said Setsuya Nakada, a professor emeritus of volcanology at the University of Tokyo.

He said Nishinoshima was also created by an underwater volcanic eruption and later grew 2km in diameter.

“There is a possibility that the (new) island could merge with Iwo Jima if the eruption continues,” Mr Nakada said.