Watching this newborn island erode could tell us a lot about Mars
Its volcanic tuff is tougher than expected and may withstand ocean waves for years
BABY PICS Scientists are keeping an eye on the rates of erosion of volcanic ash on Earth’s newest island, called Hunga Tonga-Hunga Ha’apai.
Cecile Sabau, Damien Grouille, NASA
NEW ORLEANS — Earth’s youngest bit of land is getting a new lease on life. When an erupting volcano birthed an island in the Pacific Ocean in late 2014, scientists thought waves would erode the island away within just a few months. Instead, new data suggest it could stick around for up to 30 years, researchers reported December 11 at a news conference at the American Geophysical Union’s fall meeting. Studying the life and death of this island may provide clues to Mars’ wetter past.
The new island, informally dubbed Hunga Tonga‒Hunga Ha’apai, is part of the Tonga island chain. Since January 2015, NASA satellites have tracked the island’s growth and erosion month-to-month. Scientists are using those data to estimate its life span, said James Garvin, chief scientist of NASA’s Goddard Space Flight Center in Greenbelt, Md.
In the first six months, waves rapidly eroded the volcanic tuff, hardened ash that forms the island’s central cone. Then that erosion slowed, and the island began to change shape as waves redistributed some of the eroded sediment to form a land bridge to a nearby island. Researchers now give the island six to 30 years of life — after that, only the land bridge will remain.
Garvin said the island’s life cycle may help scientists better understand Mars’ past. Finding similar erosion patterns on Mars’ volcanoes could help researchers understand whether the eruptions occurred in an ocean that’s now vanished.
