New Volcanic Cone Confirms the Havre Seamount Eruption

Multibeam sonar image of Havre seamount, with the new cone formed during the July 2012 eruption marked. Image: NIWA, GNS Science. At the end of the summer, we had a volcanic mystery that took people across the planet to solve - the occurrence of a pumice raft in the sea near the Kermadec Islands. I was lucky enough to be one of the people to help track down the potential source of the pumice raft: Havre Seamount, hitherto unrecognized as a potentially active submarine volcano. Samples of the pumice were taken to compare with samples previously collected from Havre to compare their composition as a way to confirm that Havre was the source of the raft, but now we have another piece of evidence. A group of New Zealand geologists abroad a research vessel used multibeam sonar to map the seamount and they found evidence of a new volcanic cone (see right) built on the side of the large submarine caldera that makes up most of the volcano. This cone is no small feature - the initial mapping suggests it is 240 meters tall, reaching within 1,100 meters of the surface. The pumice from Havre is still drifting in the seas near the Kermadec and will likely do so for years (or until they make landfall somewhere). However, it is great to see that our sleuthing through remote sensing has now been confirmed by direct observation of the seamount and the product of the eruption.