Tuesday, July 20, 2010

Astronomers Dig Them Some Geology Too

Emily Lakdawalla at the Planetary Society Blog has a great piece on the volcanism of Io, Jupiter's innermost large moon, and the most volcanically active body in the solar system.
Diana Blaney and her coauthors have estimated that 500 cubic kilometers of liquid hot magma erupt onto Io's surface every year; this is more than a hundred times what comes out of all of Earth's volcanoes, even when you include the mid-ocean ridges that nobody sees.
I had seen the animation below a few years ago, but it's new to this blog. From the caption: "The animation contains five images taken over an eight-minute span of time beginning at 23:50 UT on March 1, 2007. Credit: NASA / JHUAPL / SwRI"Emily's post also contains the clearest explanation of nutation I've ever seen- in high school, I was very confused about how we had pre-Apollo photos of more than 50% of our moon's surface, and the reason didn't become clear to me until later in my undergraduate career.

John at Cosmic Variance, in a post called "Here Comes Katla?" points out the uptick in seismic activity at that volcano, and posts a nice map of the recent quakes there.
In case the name Katla doesn't ring a bell, it's the big brother to Eyjafjallajokhull's little sister- the latter being the "little" volcano that disrupted flights over Europe- and because of global linkage, around the world- for weeks this past spring. At that time, it was repeatedly pointed out that historically, Katla tends to erupt when Eyjafjallajokhull does, or shortly after. The uptick in quakes prove nothing- Katla may very well remain quiet. Or it may not. If you're planning to go to Europe in the next few weeks, you might want to consider what you might do if it turns out you can't. Just sayin', this is not an alert or anything, but a suggestion to keep an eye on SE Iceland for the time being.

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