A sudden bout of seismic activity in the chain of islands due south of Tokyo has left a number of ships sunk as part of the bloody US assault on Iwo Jima in the spring of 1945 high and dry.
The decomposing hulks are what's left of 24 Japanese transport vessels captured by the US Navy in the closing stages of World War II and deliberately scuttled off the western coast of the island to form a port.
The island had no serviceable port facilities at the time, so the sunken ships were designed to serve as a breakwater to protect vessels that were unloading men and material for troops still battling the Japanese.
Marked as Brown Beach on invasion maps, the intention was to create an artificial naval base to support a major US military base on the island before the planned assault on mainland Japan.
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The plan – a version of which had been successful in the Allied attack on the beaches of northern France on D-Day in June 1944 – foundered in the Pacific and was eventually abandoned, with the ships left to sink offshore.
In recent years, the seabed off the island has begun to rise as a result of seismic activity beneath the island’s Mount Suribachi, which has recently been designated as one of the most active volcanoes in Japan.
New aerial footage of the island shows activity beneath the seabed surrounding the island, which is presently only occupied by a detachment of Japanese military personnel. Most significantly, the seabed on the western side of the island has been raised by the subterranean activity, leaving many of the sunken freighters resting on the island’s beach of volcanic ash.
The vessels are badly broken up and as there are no civilian residents of Iwo Jima – a result of the vast amounts of unexploded munitions that still litter the 8-square-mile island - there are no plans to remove them.
“The discoloured sea area has spread to surrounding areas, which indicates that the volcanic activity has not diminished yet”, Setsuya Nakada, director of the government's Volcano Research Promotion Centre, told the All Nippon News channel.
The government has listed 554-foot Mount Suribachi as one of the 10 most dangerous peaks in Japan, which has 110 active volcanoes, with Mr Nakada suggesting, “There is a possibility of a big eruption on Iwo Jima”.
Seismic activity on an island also known as “Sulphur Island” is being replicated elsewhere in the Ogasawara chain, which are some 800 miles due south of Tokyo.
A new island emerged as the result of a sub-sea eruption in August, with debris from the Fukutoku-Okanoba volcano breaking the surface and forming a horseshoe-shaped island of pumice and volcanic ash.
Another volcanic island in the chain, Nishinoshima, is active and has been releasing gases and vapour since 2013, with lava still escaping from the cone and enlarging the island.
The entire length of the Japanese island chain has experienced a sharp uptick in subterranean activity in recent weeks, with a magnitude 5.9 earthquake rattling buildings in Tokyo and a large swathe of eastern Japan on October 7. It was the largest tremor since the magnitude-9 earthquake and tsunami caused widespread devastation to the north-east of the country in March 2011.
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