April 11, 2012
The oddity of the Banda Aceh earthquake
Posted by Austin Elliott
I’ve got tons of stuff I should be doing, but I can’t resist the allure of discussion of the fascinating pair of earthquakes that happened last night in the Indian Ocean. I don’t have much of anything to add to the existing discussion, and I need to, like, get to work, so this is a “reblog” of the most thorough description I’ve seen of the setting of these quakes, by Pete Rowley on his “Lithics” blog. Note that there were two, both were massive (8.6 and 8.2), and they had a “foreshock” on January 10–sameish place, similar focal mechanism. Both of these are larger than any strike-slip earthquake we’ve recorded before, and the larger one makes it into the top 10 list of all time in any setting. It’s additionally fascinating (read: perplexing, at the moment) that they happened in oceanic crust, which is generally considered too thin to support massive strike-slip earthquakes. This will be an absolutely fascinating earthquake sequence to learn from in the coming hours, days, and weeks.