Japan has paid a high diplomatic price for its territorial disputes with China and South Korea over uninhabited islets in the East China Sea and the Sea of Japan. But Japan may get a freebie in the Pacific Ocean.

An erupting undersea volcano forms a new island off the coast of Nishinoshima (top left), an uninhabited island in the Ogasawara chain some 1,000 kilometers south of Tokyo.Reuters

Japan’s coast guard said Wednesday an underwater volcanic eruption had created a new landmass about 500 meters off the coast of the deserted Nishinoshima island, which is part of the Ogasawara island chain some 1,000 kilometers south of Tokyo.

“It’d be nice if our waters expand,” said chief cabinet speaker Yoshihide Suga. “If it develops into an island, our territorial waters could expand.”

Government officials said it was too soon to tell if the lava from the eruption would solidify into a piece of land that could stay above water during high tide to be classified as an island, as specified in the United Nations Convention on the Law of the Sea.

“There have been a number of similar volcanic eruptions in the recent past, but most [resulting pieces of land] have submerged underwater since,” the coast guard spokesman said.

Even if it survives high tide, it remains to be seen whether Japan would gain an extra slice of territory in the Pacific. The U.N. law says a country can lay claim to about 22 kilometers from the edge of its territorial base line.

“We’ll have to conduct a geographical survey to see if the new islet is indeed at the southeast edge of the Ogasawara chain in relation to the others,” a cabinet office ocean-policy official said. The Ogasawara chain consists of about 30 islands.

“Right now, the eruption is too severe for researchers to go anywhere near it,” the official said.