Last November, the volcano first broke through the ocean's surface, becoming Japan's latest piece of territory in the "Ring of Fire" -- a string of heightened seismic and volcanic activity in the Pacific that stretches from the coast of Chile north to Alaska and Siberia and then circles back down past Japan and the Philippines toward New Zealand.
Now, NASA's Earth Observatory has captured evidence of expansion: the young island has continued to erupt, growing in size, and its lava recently joined with its neighbor, claiming the remnants of a 40-year-old volcanic island as its own.
The two islands -- now one -- lie amongst the churn of the Pacific some 600 miles south of Tokyo. They're -- it's -- part of a chain known as the Ogasawara Islands, sometimes called the Bonin Islands.
"This is a great example of how volcanic island like this in the Bonin Islands grow over hundreds to thousands of eruptions," volcanologist and blogger Erik Klemetti wrote in a post for Wired earlier this year.
When it first emerged, scientists didn't think Niijima would last much more than a few years. But with its continued growth -- it's now six-tenths of a mile across and nearly 200 feet tall -- it may stick around for longer.
"A lot of it depends on how fast it erodes," Ken Rubin, a professor at the University of Hawaii at Manoa and an expert in submarine volcanism, told CNN. "Until it shuts off, it's too soon to tell."