Volcano raises new island off Japan

A new islet about 200 metres in diameter has been formed by a volcanic eruption in the seas to the far south of Tokyo.

A volcanic eruption has raised a new island in the seas to the far south of Tokyo, the Japanese coast guard and earthquake experts say.

The coast guard and the Japan Meteorological Agency said the islet is about 200 metres in diameter.

It is just off the coast of Nishinoshima, a small, uninhabited island in the Ogasawara chain, which is also known as the Bonin islands.

The approximately 30 islands are 1000 kilometres south of Tokyo and along with the rest of Japan are part of the seismically active Pacific "Ring of Fire."

The coast guard issued an advisory warning of heavy black smoke from the eruption.

Television footage showed heavy smoke and waters roiling over the crater.