“As the largest and deepest submarine silicic eruption ever documented, this was likely to be a ‘once in a century’ event.”
“It was likely twice the size of the renowned Mount St Helens eruption of 1980, and perhaps more than 10 times bigger than the 2010 Eyjafjallajokull eruption in Iceland.”
From time to time members of the public, untrained in science, make important discoveries. This is what happened in July, 2012 when a commercial airline passenger noticed something odd from her window seat. Far below, drifting on the ocean waves, she spotted large rafts of a light-brown substance.
The material turned out to be pumice – a porous, lightweight volcanic material with a density less than that of water, enabling it to float on the ocean for years.
Geoscientists were alerted to the possibility that the pumice had been blasted to the surface by an undersea eruption in the area, a maritime region known as the Kermadec Arc. This is a volcanic chain on the seafloor extending for thousands of kilometres north of Auckland in New Zealand.
Poring over comprehensive, high-resolution satellite images, the scientists subsequently confirmed the presence of gigantic rafts of silicic pumice, covering an area spanning roughly 400 square kilometres. They traced the rafts back in time to their source on July 18, when there was also evidence of an atmospheric plume, emitted from a point source, and a thermal hotspot.
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