An erupting volcanic island that is expanding off Japan could trigger a tsunami if its freshly-formed lava slopes collapse into the sea, scientists say.
An undersea volcano has created a new Japanese island 620 miles south of Tokyo. The eruption took place 500 meters from the uninhabited Nishinoshima Island.
The small, but growing, island appeared last year and quickly engulfed the already-existing island of Nishinoshima, around 1000 kilometres south of Tokyo.
It now covers 1.26 square kilometres.
The island's craters are currently spewing out 200,000 cubic metres of lava every day - enough to fill 80 Olympic swimming pools - which is accumulating in its east, scientists said.
"If lava continues to mount on the eastern area, part of the island's slopes could collapse and cause a tsunami,"
warned Fukashi Maeno, assistant professor of the Earthquake Research Institute at the University of Tokyo.
Chichijima, in the path of a possible tsunami.
He said a rockfall of 12 million cubic metres of lava would generate a one metre tsunami that could travel faster than a bullet train,
hitting the island of Chichijima - 130kms away - in around 18 minutes.
Chichijima, home to about 2000 people, is the largest island in the Ogasawara archipelago, a wild and remote chain that is administratively part of Tokyo.