Tag: Havre Seamount

Floating rocks in the ocean lead to an undersea eruption… seen from space!

By Phil Plait | August 21, 2012 6:44 am

[Note: At the bottom of this post is a gallery of more amazing pictures of volcanoes taken from space.]

Sometimes, the best way to observe the Earth is to get off it. It really helps if you want to solve some mysteries.

And scientists had a good one on their hands in recently. You should really read the journal of science journalist Rebecca Priestly, who reported on all this first hand, but here’s a summary. On August 9, the crew of the HMNZS Canterbury were on a scientific voyage in the Pacific when they got word to change course. A huge anomaly was reported near their position, and it looked like it might be a gigantic floating "raft" of pumice, possibly from an undersea eruption. They got samples, and sure enough it was pumice. Such rafts have been seen before from other volcanic eruptions.

But what volcano was at the root of this one? Early guesses were that it was from Monowai, which had recently erupted in early August. But satellite imagery taken on July 19 – weeks earlier – pinpointed the location of the raft’s origin:

[Click to hephaestenate.]

This image, taken by NASA’s Terra Earth-observing satellite, shows the eruption of the Havre Seamount, located a few hundred kilometers northeast of Auckland, New Zealand. The plume is clearly visible. The gray patch right in the middle of the picture is the floating island of pumice. To the left of the plume is teal water, stained by ash. The volcano itself is more than a thousand meters under the sea’s surface, but the eruption was strong enough to break through. At the time this image was taken, the raft was already about 15 kilometers (9 miles) long. It eventually grew to more than 20,000 square kilometers (about 10,000 square miles).

This area of the ocean is very, very large, and without satellite images the exact location of this volcano would have been very difficult to spot. Scientists from Tahiti and New Zealand were able to connect earthquake reports on July 17 and 18 to the event (even though they occurred long before the raft was first sighted), and then other scientists were able to find the above image in the Terra archives. It took collaboration, people from around the world, and the open nature of science to be able to find the culprit volcano behind this mysterious event.

Science! Solving mysteries we otherwise couldn’t! I love this stuff.

Image credit: Jeff Schmaltz, LANCE MODIS Rapid Response Team at NASA GSFC


CATEGORIZED UNDER: Cool stuff, NASA, Pretty pictures, Science

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