Geologists have traced the origin of a huge floating "island" of floating pumice in the Pacific Ocean, which is three times the size of Sydney Harbor and twice the size of Manhattan.
They say that the 150-kilometer mass of pumice was produced by the eruption of an underwater volcano 50 kilometers northwest of the Tongan island of Vava'u.
Geologists have correlated the location of the volcano, simply known as "Volcano F," with images of huge eruption plumes captured by satellite imagery.
The giant island of volcanic pumice was originally seen floating in the Pacific Ocean back in August.
“When I then saw the reports of the pumice island in the media in the summer, I became curious and began to investigate with my colleagues the reasons for its appearance,” said Philip Brandl, the first author of the study.
Dr. Brandl and his team studied images from the European Space Agency's Copernicus Sentinel 2 satellite.
Images taken by the satellite on August 6 this year showed traces of an active underwater eruption on the surface of the water, including plumes of steam and ash. The traces of the eruption closely match the seabed maps that the team had previously surveyed.
“The traces of the eruption correspond exactly to Volcano F,” said Dr. Brandl.
The team previously used sonar scanning between December 2018 and January 2019 to survey the seabed around the volcano.
The bottom of the large central caldera of volcano F, which forms soon after the emptying of the magma chamber, is located at a depth of 700 meters below the surface of the water.
The team tracked the drift of the pumice island until mid-August. It drifted slowly westward and reached an area of 167 square kilometers - about twice the size of Manhattan.
At its current direction and speed, the pumice island will collide with Australia's Great Barrier Reef in late January or early February.
But this is good news for underwater life, the researchers say, as the pumice stone may act as the basis for marine life that will replenish the Great Barrier Reef.
"When it gets to Australia, it will spread from Townsville in northern Queensland to the very south of North NSW," said Scott Bryan, assistant professor of geology at Queensland University of Technology.