In a remarkable geological development, a new island has emerged from the depths of the Pacific Ocean near Japan’s Ogasawara Islands, also known as the Bonin Islands. The island, which is the youngest among its neighbours, was formed due to an undersea volcanic eruption that started on October 21.
Formation through Volcanic Eruption
According to volcanologist Setsuya Nakada from the University of Tokyo, the formation of the island began with a “vertical jet” of solidified magma shooting high above the ocean surface. The eruption continued with sustained bursts of debris falling back into the ocean as lava, combined with a porous, low-density material called pumice. These materials accumulated until the mound of rock was tall enough to emerge from the water.
THE YOUNG ISLAND’S DETAILS
As of November 3, the undersea volcano had shifted to mainly ejecting ash. The new land mass, which is visible from Iwo Jima—an island about 1,200 kilometres south of Tokyo—lies just over a kilometre off the coast. As of Friday, the young island stretched about two kilometres in diameter, although it doesn’t sit far above the water line.
THE ISLAND’S FUTURE
The eruption seems to have reached its peak and is now calming down. Although the new land mass might slightly grow in the coming days, any uncemented pumice could be eroded away, causing uncertainty about the island’s future longevity. Nakada notes that submarine volcanic eruptions in this region usually continue only for about a month.
SUBMARINE VOLCANOES: A WINDOW INTO THE PAST
While much is known about the land-based volcanoes in the Ring of Fire, little is known about the vents and fissures on the ocean floor. Scientists estimate there are over a million submarine volcanoes worldwide, many of which are probably extinct or too deep to observe above water.
Observing the formation of islands from these eruptions is even rarer, but it provides valuable insights into how many Pacific islands, including the Hawaiian Islands, were formed millions of years ago.
For instance, a new island emerged in the South Pacific in 2015 due to an undersea volcanic eruption, providing an excellent opportunity for scientists to study it. However, by 2022, it had disappeared due to another eruption.