Newly Formed Island From Japan’s Unnamed Undersea Volcano Eruption May Not Last Long, Expert Says

Last month, an unnamed undersea volcano in Tokyo, Japan, erupted. The eruption paved the way for forming a new island, which experts believed may not last long.

Fate of the New Island From Japan's Undersea Volcano Eruption

A still unnamed undersea volcano about 1 kilometer off the southern coast of Iwo Jima erupted three weeks ago. It started its series of outbursts on Oct. 21, and for ten days, ashes and rocks piled on the shallow bed.

According to Yuji Usui, an analyst in the Japan Meteorological Agency's volcanic division, the disturbance gave birth to a new island about 100 meters (328 feet) in diameter and 20 meters (66 feet) high.

Usui said the formation of the new island was a significant development after the increasing volcanic activity in the area and a series of similar undersea eruptions in recent years. However, the fate of the new island is uncertain, and it might not even last long.

As the volcanic activity at the site subsides, the newly formed island has reportedly shrunk. Per Usui, this is due to the lack of foundation because the waves can easily wash away the island's "crumbly" formation.

Experts are still analyzing the development but believe the island will likely survive longer if made of lava or more volcanic rocks like pumice.

"We just have to see the development," Usui said. "But the island may not last very long."

This isn't the first time undersea volcanoes and seismic activities have resulted in new islands. There have been several reported cases like this in the past.

For instance, a volcanic eruption at Nishinoshima in the Pacific Ocean south of Tokyo in 2013 also led to the formation of a new island, which kept growing during a decade-long eruption.

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Formation of New Landmass From Eruption

Setsuya Nakada, a volcanologist at the University of Tokyo, explained how an underwater volcanic explosion created a new island. A "vertical jet" of hardened lava erupted far above the waves to start the eruption, and it continued in short bursts after that.

Something resembling a periscope slowly rose above the water as the rubble, which included pumice and lava, fell back into the sea. If volcanic activity continues, the newly formed island, mainly made up of rock masses generated north of the eruption site, may grow.

The new island was formed on Oct. 30 following the eruption of an undersea volcano that caused the accumulated hardened magma to start rupturing the surface. On Nov. 3, Nakada saw that the eruption had changed, releasing large amounts of volcanic ash.

Even though the isle is prone to erosion, Nakada believed continuous volcanic activity might shield its existence. If the lava flow continued, it would protect the isle and increase the likelihood of it remaining permanently. However, as mentioned, the volcanic activity has subsided, and the island has shrunk.