Japan Has A New Island Thanks To Underwater Volcano Eruption

Will it stay as small as it is? Or will it disappear completely? Image credit: Japan Coast Guard

There are canonically 6,852 islands that make up Japan, which is probably more than you would have expected. But as of this week that number has increased by one – at least for now – thanks to the eruption of the undersea volcano Fukutoku-Okanoba.

The new landmass is located about 1,200 kilometers (745 miles) south of Tokyo, near to the island of Iwo Jima. It made its debut on August 13, but it wasn’t until two days later that its entrance into the world was picked up by the Japanese coast guard. They reported plumes of steam and gas rising over 15 kilometers (9.3 miles) into the sky – for reference, that’s just about the upper limit on how high airplanes can fly before they start getting damaged – as well as pieces of pumice created by the eruption floating across a 60-kilometers (37 miles) wide area of ocean. Eventually, the coast guard were able to make out the shape of the new island: a crescent.

 

At the moment, the new island is just a baby – only about 1 kilometer in diameter. But Japan’s Meteorological Agency believes that the eruption is still ongoing, and has issued smoke and ash warnings for the area while they monitor the volcanic activity. Per Forbes, the anticipation is that the entire caldera of Fukutoku-Okanoba – the large cauldron-like depression that results when a volcano’s magma chamber empties and collapses in on itself – might eventually rise above the ocean surface.


Should the new island prove a permanent fixture, there may be geopolitical ramifications. It’s located near to the southernmost islet of Japan’s Ogasawara or Bonin Island chain, so it could result in Japan expanding its territorial claims, albeit only by a few hundred meters – though local media say that this is unlikely even if the island remains above the surface.

You read that right, by the way – the island may not stick around. It might sound strange, but Japan has something of a history of landmasses turning up only to disappear soon afterwards: new islands that were confirmed in 1904, 1914, and 1986 all disappeared pretty quickly. The most recent of those only lasted about two months thanks to erosion from waves and currents. Sometimes they go missing and it takes a while for someone to notice.

On the other hand, some islands have proved more permanent. In 2013, a volcanic island dubbed Niijima grew so large that it merged with a neighboring landmass and gifted the world “Snoopy Island”. Although it no longer looks like a cartoon beagle, that island – now known as Nishino Shima – is still there, and as of last year, still growing.

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The key to the new island’s future, scientists say, will be what it’s made of. If the island turns out to be formed of ash and rock fragments, then it’s unlikely to fare well against the ocean. But if, as the meteorological agency believes, the volcanic eruption is set to continue, then it may produce enough lava flow to create a more permanent landmass – one which we can only hope will eventually resemble Woodstock.


 This Week in IFLScience

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