A new island has surfaced off the coast of Japan, the apparent result of volcanic activity.

Experts aren't sure when the island was created since it popped up in an uninhabited area, near the island Nishinoshima in the Sea of Japan, but smoke was seen in the area on Wednesday.

The new island is 666 feet in diameter, but Japanese officials are waiting to see if the island becomes permanent before they name it.

"It's a matter of if it's going to break apart," Darcy Ogden, volcanologist and assistant professor at UC San Diego, told ABC News. "It's made of a big pile of rocks. If they aren't stuck together very well they will erode and break down."

The island is located in what's called the "Ring of Fire," a hotbed of some 400 volcanoes spanning 25,000 miles in the Pacific Ocean.

"In the deeper ocean we know less because the activity doesn't register on the ocean's surface," said Bill Chadwick, a research professor who studies submarine volcanoes at Oregon State University.

A new island off the coast of Pakistan appeared shortly after a Sept. 24 earthquake in that country. Officials are waiting to see if that island becomes permanent or sinks back into the sea.

Smoke billows from a new island off the coast of Nishinoshima, an island in the Ogasawara chain south of Tokyo, Japan, Nov. 20, 2013. Japan Coast Guard/AP Photo