Tonga is home to 170 islands. A new one just formed from an underwater volcanic eruption.

The Pacific nation of Tonga is made up of 170 islands, but it just welcomed its newest addition – thanks to an underwater volcano.

Near the center of the nation's island formation lies the Home Reef volcano in the South Pacific. On Sept. 10, the volcano began to erupt for the first known time since 2006, oozing lava and ejecting plumes of steam and ash in and above water, according to NASA's Earth Observatory.

Just 11 hours after the eruption began, a new island had appeared, and NASA confirmed its formation with satellite images.

When the island was first examined on Sept. 14, it was estimated to be one acre with an elevation of 33 feet. On Monday, the Tonga Geological Services said latest estimations show the island has grown to 8.6 acres and now has an elevation near 50 feet above sea level.

This handout satellite imagery released on September 16, 2022 by Planet Labs PBC and captured on September 14, 2022, shows the Home Reef Volcano in Tonga, where researchers noticed new seismic activity and venting.
This handout satellite imagery released on September 16, 2022 by Planet Labs PBC and captured on September 14, 2022, shows the Home Reef Volcano in Tonga, where researchers noticed new seismic activity and venting.

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Monday also marked the 17th straight day of effusive lava flow, but the continuous volcanic activity poses a low risk to the nearby Vava'u and Ha'apai communities. Mariners are advised to sail beyond two and a half miles away from the eruption.

While this may seem like a new addition to the Pacific nation, it's not likely the island will stay; NASA says islands created by underwater volcanoes are "often short-lived."

Home Reef has even created some of these short-lived islands. Small islands were formed after eruptions in 1852, 1857, 1984 and 2006, with the last two created islands with peak elevations of 164 feet and 229 feet, respectively.

But hope does remain for the island to have a longer life. NASA added in 1995, the nearby Late‘iki volcano created an island that eventually existed for 25 years.

Follow Jordan Mendoza on Twitter: @jordan_mendoza5.

This article originally appeared on USA TODAY: New island forms in Tonga after underwater volcano erupts