Sunday, April 18, 2010

VEI

VEI stands for Volcanic Explosivity Index, and The Christian Science Monitor has a nice article using it to designate the "Five Biggest Volcanic Eruptions of Recent History."
By the measure of the Volcanic Explosivity Index (VEI) – a sort-of Richter scale for eruptions – the current outburst is probably a 2 or a 3, experts say. In other words, eruptions like Eyjafjallajökull happen virtually every year somewhere in the world.

The biggest eruption of the past millennium, by contrast, was a 7. Given that each number on the scale represents an eruption 10 times more powerful than the previous, that means Eyjafjallajökull is 10,000 times less powerful than one in Indonesia's Sunda Islands in 1815.
There are several points in this article that I really appreciate. First, they are objectively ranking the eruptions on a standard criterion. As a result, Mount St. Helens, which almost always makes these lists, isn't even mentioned. It may be the most famous eruption in the US, volcanologists learned a tremendous amount from that eruption, and it certainly influenced my academic direction, but as volcanoes go, it just wasn't that big.

Second, there were a few tidbits that were new to me, for example, in the discussion of Tambora, I learned that, "The eruption is also tangentially credited with the invention of the bicycle, as the cost of maintaining horses rose, both because of the cost of oats and the death of many horses."

Third, somehow, I don't remember ever hearing of the Santa Maria eruption.
Santa Maria

Oct. 24, 1902

The least powerful of the VEI 6 eruptions recorded since the beginning of the 1700s, the Santa Maria eruption hit the Pacific coast of Guatemala. The 1902 eruption was the first in the recorded history of the mountain, spewing ash that was detected as far away as San Francisco.
Well done, CSM!

1 comment:

Jessica Ball (AKA Tuff Cookie) said...

The Santa Maria eruption is one I'm pretty familiar with, since it was the precursor to the domes forming at Santiaguito (here's the most recent post where I mentioned it). It does seem to get lost in history a bit, though, probably because there weren't a whole lot of Europeans or Americans in Guatemala at the time.