Defence Force Locates 7500Sq Miles of Pumice From Underwater Volcano

10 August 2012

The sea of pumice as seen from the RNZAF Orion

An area of floating pumice 250 nautical miles in length and 30 nautical miles wide was spotted in the South Pacific ocean yesterday by a Royal New Zealand Air Force (RNZAF) Orion.

The RNZAF Orion, which was on Maritime patrol from Samoa to New Zealand, relayed the information to HMNZS CANTERBURY and last night, approximately 85 nautical miles West South-West of Raoul Island CANTERBURY spotted the phenomenon.

Lieutenant (LT) Tim Oscar, a Royal Australian Navy officer on a three year exchange with the Royal New Zealand Navy, saw what he describes as, "the weirdest thing I've seen in 18 years at sea."

"The lookout reported a shadow on the ocean ahead of us so I ordered the ship's spotlight to be trained on the area.

"As far ahead as I could observe was a raft of pumice moving up and down with the swell.

"The rock looked to be sitting two feet above the surface of the waves, and lit up a brilliant white colour in the spotlight. It looked exactly like the edge of an ice shelf," said LT Oscar.

LT Oscar said he had been briefed by GNS Volcanologist Helen Bostock the previous day when the ship first encountered an area of pumice from an undersea volcano.

"I knew the pumice was lightweight and posed no danger to the ship. None the less it was quite daunting to be moving toward it at 14 knots. It took about 3 - 4 minutes to travel through the raft of pumice and as predicted there was no damage. As we moved through the raft of pumice we used the spotlights to try and find the edge - but it extended as far as we could see."

HMNZS CANTERBURY is on passage from Auckland to Raoul Island in the Kermadec Group with a party of GNS scientists onboard. The Commanding Officer, Commander Sean Stewart changed course to intercept the pumice, and brought the ship to a halt to enable retrieval of samples. The samples will be analysed to determine which volcano they came from.

According to GNS Science the underwater volcano, Monowai, has been active along the Kermadec Arc and the pumice could be a result of that activity.

The GNS scientists onboard believe the volcanic activity of Tongariro, White Island and along the Kermadec arc is unrelated.


For more information contact Defence Communications Group on 021 186 4111

This page was last reviewed on 31 January 2013.