JAPAN (CNN) -- Japan Coast Guard officials say an island formed by volcanic activity in Tokyo's Ogasawara island chain keeps growing.
The land mass surfaced off Nishinoshima Island about a 1000 kilometers south of Tokyo.
The coast guard officials say it is about 2.5 times bigger than when it was spotted on November 20th. Sunday, they conducted an aerial survey and determined that the islet is now 250 meters wide and 200 meters long.
Officials now say they've found three craters pushing out ash and lava that are helping to make the islet grow.
Coast guard researcher Koji Ito said the island is growing as lava flows from the craters. He said officials will continue to monitor the islet's activity.
The eruption was the first in 40 years in the Ogasawara chain. It occurred about 130 kilometers off the closest inhabited island.