Tuesday, May 13, 2008

Chaiten Volcano

If you're interested in volcanoes, you've probably seen a steady stream of news about Chile's Chaiten Volcano over the last couple of weeks. Some of the photos have been pretty spectacular.

The above is a satellite image showing the ash plume extending across South America. (From here; there are quite few other cool pictures in this article)
A lightning storm in the ash column. (From here; more pics here too) There is an enormous version of this pic here (388K).

This style of eruption is called plinian after Pliny the younger, who witnessed and described the cataclysmic eruption of 79 AD that destroyed Pompeii and Herculaneum. Plinian eruptions are characterized by enormous vertical columns of ash. These columns are often supported at least in part by the force of newer material jetting from the mouth of the volcano below. If the volcano slows or stops erupting, the column may collapse due to loss of that support. This can be disasterous: imagine hurricane to tornado-force winds full of burning hot volcanic ash. It was this sort of event that buried Pompeii. Ominously, there are indications that this could also happen at Chaiten. Reuters is carrying a story stating that minor collapses have already occurred due to fluctuations in the force of the eruption and that, "Thousands of people have been evacuated from within a 30-mile radius of Chaiten volcano, 760 miles south of the capital Santiago."

Finally, for those that are familiar with or fans of The Flying Spaghetti Monster (picture, further background), this will blow you away. I haven't been able to link directly to the picture, or download it, but go here, and go to picture #4. I may not have been touched by his noodly appendages, but now I've seen them.

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