Saturday, November 02, 2013

Wired Magazine: Building toward a volcanic caldera event in South America?

Image Courtesy of NASA and the US / Japanese ASTER Science Team

A Caldera in the Making?: The Curious Story of Laguna del Maule - Wired Science:

'via Blog this'

This swelling volcanic basin is the most, um, well promising candidate we know of for a large caldera-forming event. Lots of small, dribbling eruptions of rhoylite from what looks like a large magma source not far below the surface. It also has an apparent uplift of 30 meters in over the last century, which would put the sedate rises and falls of the Yellowstone plateau to shame if true. What's missing from the potential super volcano eruption scenario? The kind of outgassing associated with the gas-rich magma that generates truly violent and colossal Plinian ash eruptions. What does it mean? No one knows for certain. There's still a lot for us to learn when it comes to the largest classes of volcanic events.

What's fascinating about this for me, is the pre-eruption similarities between Laguana del Maule and the Long Valley Caldera in Eastern California. The latter is the one super volcano I've seen in person, having driven through it several times as a child and twenty-something. It's an interesting landscape with many indications of cataclysmic geologic violence, if you know how to read those signs. Searing ash winds that welded themselves into lateral waves and descending columns of solid stone, and bisected hills and mountains that were partially devoured when the vast caldera floor collapsed several kilometers after a days-long ash discharge that buried much of what is now the Southwestern United States.

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