NASA Satellites Pinpoint Volcanic Eruption That Caused Floating Pumice Sightings
Posted on August 14, 2012
NASA satellites have pinpointed the underwater volcanic eruption that caused the recent floating pumice sightings. The floating pumice - which resembled a polar ice shelf - was spotted by crew on board the HMNZS Canterbury, a New Zealand Navy ship on voyage from Auckland to Raoul Island. The Daily Mail reports that a ship lieutenant called it the "weirdest thing I've seen in 18 years at sea."
Volcanologist Erik Klemetti and NASA visualizer Robert Simmon examined a month's worth of satellite imagery from NASA's Moderate Resolution Imaging Spectroradiometer (MODIS). They discovered the first signs of the eruption - ash-stained water, gray pumice, and a volcanic plume - in imagery from 9:50 a.m. and 2:10 p.m. (local time) on July 19, 2012. Klemetti matched the satellite imagery with ocean floor bathymetry to identify Havre Seamount as the likely source. NASA says the eruption was strong enough to breach the ocean surface from a depth of 1,100 meters (3,600 feet). NASA also says winds and currents spread the pumice over an area 280 by 160 miles.
Larger satellite images of the eruption site can be found here on NASA's Earth Observatory website.