NASA's Earth Observatory reports that Niijima island, a volcano which broke through the ocean's surface last November, has now merged with a nearby island that formed from a volcano which last erupted 40 years ago.

Niijima emerged about 500 meters (550 yards) from the older Nishinoshima in November. Now, according to observations taken at the end of March, they are one, measuring about a kilometer (six-tenths of a mile) across. And at its highest point, the new island is 60 meters (almost 200 feet) above sea level. That's triple the highest point observed in December, according to the NASA report.

Niijima island spews jets of stream and ash near Nishinoshima island on November 21. Niijima emerged about 500 meters (550 yards) from the older Nishinoshima in November, and now they are one, according to NASA's Earth Observatory. Click through the gallery to see the change over time.

At its size in December, the new island was expected to last several years, according to Japanese scientists. Because it has continued to grow, it could last much longer.

(Source: CNN)