Most newly formed volcanic islands tend to disappear fairly rapidly. Erosive effects of waves tend to quickly reclaim any newly formed land out in the ocean. Forming out of underwater eruptions, only three islands in the last 150 years have survived past a few months. The first newly formed island to survive in the age of remote sensing is an island that formed four years ago near the in the South Pacific island nation of Tonga. In December of 2014, a submarine volcano erupted, and by January of 2015 when the ash from the resulting 30,000 feet (9 kilometers) high plumes cleared, a small island formed between two two older islands was visible on satellite imagery. NASA researchers in 2017 predicted the island will last about 6- to 30-years.
Named unofficially Hunga Tonga-Hunga Ha’apai (a combination of the names of its two neighboring islands), NASA scientists have been tracking the fate of the island ever since:
After four years of remotely tracking the island’s topographical changes, NASA scientists along with students from Woods Hole’s Sea Education Association (SEA) were finally able to pay the island a visit in person. This gave them the opportunity to see the island up close and take GPS measurements notable features such as boulder elevations and areas of erosion visible in satellite images. NASA researcher Dan Slayback commented, “We were all like giddy school children. Most of it is this black gravel, I won’t call it sand – pea sized gravel – and we’re mostly wearing sandals so it’s pretty painful because it gets under your foot.” The researchers were also surprised by the presence of clay washing out of the cone: “In the satellite images, you see this light-colored material. It’s mud, this light-colored clay mud. It’s very sticky. So even though we’d seen it we didn’t really know what it was, and I’m still a little baffled of where it’s coming from. Because it’s not ash.”
Life has begun to colonize the island. Vegetation likely seeded from seabird droppings was growing. Nesting sooty terns were spotted in deep gullies etched into the cliffs of the island.
- Land Ho! Visiting a Young Island, NASA Earth Expeditions
- NASA Shows New Tongan Island Made of Tuff Stuff, Likely to Persist Years, NASA Science