Giant mass of floating pumice indicates third volcanic eruption near New Zealand

August 10, 2012 – NEW ZEALAND – A floating mass of the volcanic rock, pumice, reportedly covering 25,000 square km, has been found floating in the South Pacific, indicating a third volcano is active near New Zealand. The New Zealand Defense Force (NZDF) said Friday the floating pumice, measuring 250 nautical miles long and 30 nautical miles wide, was first spotted by a New Zealand air force Orion on a maritime patrol from Samoa to New Zealand. The Orion relayed the information to New Zealand navy vessel HMNZS Canterbury, which spotted the pumice late Thursday about 85 nautical miles west southwest of Raoul Island, one of the Kermadec Islands that lie 750 to 1,000 km northeast of New Zealand. Lieutenant Tim Oscar, a Royal Australian Navy officer on exchange with the Royal New Zealand Navy, described the pumice 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,” Oscar said in the NZDF statement. As far ahead as I could observe was a raft of pumice moving up and down with the swell,” he said. The rock looked to be sitting 2 feet (60 cm) above the surface of the waves, and lit up a brilliant white color in the spotlight. It looked exactly like the edge of an ice shelf.” Oscar said he had been briefed by a volcanologist from New Zealand’s Institute of Geological and Nuclear Science (GNS Science) the previous day when the ship encountered another area of pumice from an undersea volcano. I knew the pumice was lightweight and posed no danger to the ship. Nonetheless it was quite daunting to be moving toward it at 14 knots. It took about three to four minutes to travel through the raft of pumice and as predicted there was no damage,” he said. “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 was en route to Raoul Island with a party of GNS scientists aboard at the time. The Commanding Officer, Commander Sean Stewart, changed course to intercept the pumice and retrieve samples, which would be analyzed to determine which volcano they came from, said the statement. According to GNS Science, the underwater volcano, Monowai, had been active along the Kermadec Arc and the pumice could be a result of that activity, said the NZDF statement. The find comes after eruptions from Mount Tongariro, in New Zealand’s central North Island, late Monday and White Island, a marine volcano about 50 km off the east of the North Island, two days later. The GNS scientists aboard the Canterbury believed the volcanic activity of Tongariro, White Island and along the Kermadec arc was unrelated, said the NZDF statement. –News Track

Eruption may have occurred a month ago: A large pumice raft spotted floating in the Pacific Ocean was formed nearly a month ago when an unknown volcano erupted, scientists have determined. An Air force Orion spotted the huge raft, measuring 463 kilometres by 55 kilometres, on Thursday, and samples were collected later in the evening by the navy’s HMNZS Canterbury. Vulcanologists had thought it might have been produced by New Zealand’s third erupting volcano, the undersea mountain Monowai, but that theory has now been put to rest. Monowai started erupting on August 3, whereas scientists have determined the pumice raft was first spotted on July 19. An Air New Zealand pilot also took a photograph of it on August 1. Tahitian vulcanologists have determined that the raft became visible on July 19 and was caused by a volcanic eruption associated with a series of earthquakes in the days prior. They have pin-pointed the origin of the raft to 72 kilometres south west of Curtis Island, one of the Kermadec islands, halfway between New Zealand and Tonga. More than 157 earthquakes between magnitude 3 and 4.8 occurred in the area between July 17 and 18, the Laboratoire de Geophysique told their colleagues at GNS Science. GNS vulcanologist Brad Scott said he was unaware of any volcano in the specific location where the raft was believed to have originated from.  “At this time I don’t know if we could identify a sub-marine volcano at that location,” Scott said. It could have been emitted from a previously-unknown volcano, or it could be that others have knowledge of a volcano in the area while he doesn’t, he said. GNS would be liaising with colleagues to help determine what undersea volcano the pumice came from. –Stuff