Volcanic island eats another off Japan

Niijima island spews jets of steam 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.

Two volcanic craters are shown on Niijima on November 22. The island emerged about 1,000 kilometers (600 miles) south of Tokyo in the Ogasawara Islands, also known as the Bonin Islands.

Niijima is seen behind Nishinoshima on November 26.

The Advanced Land Imager on NASA's Earth Observing-1 satellite captured this natural-color image of the two islands on December 8.

Niijima, bottom right, and Nishinoshima are seen conjoined on December 26.

This satellite image of volcanic activity, collected on December 31, shows Niijima merging with Nishinoshima.

On March 30, the Operational Land Imager on the Landsat 8 satellite captured this image of the combined island. The merged island is now slightly more than six-tenths of a mile across.

• Island emerged from sea in November


• Newly merged island now measures a kilometer across


• Continuing eruption means island could have long life

(CNN) -- One Japanese island has swallowed another.

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.

Japanese volcano creates new island

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.

"A lot of it depends on how fast it erodes," Ken Rubin, a University of Hawaii at Manoa professor and expert in deep submarine volcanism, told CNN after the island broke the surface last year. "Until it shuts off, it's too soon to tell."

The island sits on the Pacific "Ring of Fire," which stretches from the coast of Chile north to Alaska and Siberia and then south to New Zealand.

The newly merged island is about 1,000 kilometers (600 miles) south of Tokyo in the Ogasawara Islands, also known as the Bonin Islands.

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