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Where fire freezes: All eyes, ears and instruments on Iceland's volatile volcanoes

Tue, 29 Mar 2016 18:35:15 -0400

In 1996, Grímsvötn Volcano erupted beneath the Vatnajökull Ice Cap, triggering a massive glacial outburst flood, called a jökulhlaup, that discharged 300,000 cubic meters per second as it flowed across the Skeidarársandur, a glacial outwash plain on the southern coast of Iceland. Credit: USGS/Icelandic Meteorological Office, Oddur Sigurdsson.

With examples of every type of volcano on Earth, and about a third of the island’s more than 30 active volcanic systems buried under glacial ice, Iceland earns its nickname: the land of fire and ice.

The question of mantle plumes

Mon, 14 Dec 2015 08:49:28 -0500

Over the years, many different locations have been proposed as hot spots. Some of the most well-known proposed sites are labeled with red dots in this diagram, which also depicts the borders of Earth's tectonic plates. Credit: K. Cantner, AGI.

In 1963, J. Tuzo Wilson first proposed that volcanic chains like the Hawaiian Islands form when a tectonic plate drifts over a “hot spot” in the mantle. Eight years later, Princeton geophysicist W. Jason Morgan suggested that such hot spots — he initially proposed about 20 around the world — were fueled by narrow plumes of hot mantle rock rising from the core-mantle boundary.

Travels in Geology: Taking in Hawaii's Big Island

Thu, 05 Jan 2012 06:41:58 -0500

The Big Island of Hawaii, with two snow-topped peaks: Mauna Loa, to the south, and Mauna Kea, to the north. NASA Earth Observatory

For a bit of money, visitors to Hawaii can indulge their touristy impulses with a single night of mai tais and luaus. But take on Hawaii’s geologic hallmarks, and you’ll embark on a low-cost safari that will last you all week.