A pumice raft spotted by a Royal New Zealand Air Force crew has pointed to a possible major undersea eruption somewhere in the Tonga-Kermadec volcanic arc in the Pacific Ocean.
The crew was on patrol on November 16 when it came across the mass of floating pumice on the ocean surface, about 80 nautical miles west of Minerva Reef, south of Fiji.
They reported the raft to GNS Science scientists, who then looked to satellite images to check where it came from.
"Normally you can go back and track them using the satellite images to compare where they first appeared and where are now," GNS volcanologist Brad Scott said.