The emerging hulks are the remains of the 24 Japanese transport vessels captured by the US Navy in the spring of 1945 at the end of World War 2 and deliberately scuttled off the western coast of the island to form a port. During that time, the island had no serviceable port facilities, so the sunken vessels were used as a breakwater to protect others unloading men and supplies for troops during the battles with the Japanese. Their blueprint had been to form an artificial naval base to support a huge US military base on the island prior to the assault on mainland Japan.
But the plan crumbled in the Pacific and was eventually scrapped, with the ships left to sink offshore.
Recent seismic activity beneath the island’s Mount Suribachi, which has 110 active volcanoes, has seen the seabed raise around it.
The last known major activity was reported in May 2012, when the Japanese Meteorological Agency reported a small eruption that caused water discolouration to the northeast.
Newly-released footage of the island shows is beginning to show activity beneath the seabed surrounding the island, currently occupied by a group of military personnel from Japan.
The seabed on the western side of the island has been raised, bringing any of the sunken freighters to the surface, resting on the island’s nearby volcanic ash.
They are heavily decomposed following nearly 80 years of being deep underwater and because there are no civilian residents of Iwo Jima, they are likely to remain there for the time being.
Setsuya Nakada, director of the government’s Volcano Research Promotion Centre, told the All Nippon News channel: “The discoloured sea area has spread to surrounding areas, which indicates that the volcanic activity has not diminished yet.
He suggested: “There is a possibility of a big eruption on Iwo Jima.
Over recent weeks, there has been a surge in subterranean activity across the length of the Japanese island chain, with a strong magnitude 5.9 earthquake on October 7 shaking buildings across a large area of eastern Japan.
This is the most significant since March 2011, when a magnitude 9 earthquake smashed the country.
This triggered a massive tsunami that caused widespread devastation to the northeast of Japan. Nearly 20,000 people were killed in total.