I seem to be out of town for most of the disasters that strike LA. I was doing an overnight concert near Palm Springs when the Simi wildfire came close to our house in ’03, and drove back at 6am to find the side of the freeway burning. The last noticeable earthquake we had I was up in Cupertino on business, so I had to settle for hearing about it from Liz. I was actually quite glad to be home when the latest one struck, both so I didn’t have to worry from a distance, and so I could feel more like a true Angeleno.
One thing that impressed me while watching the news roundup was the quality of the visualizations. There was one animation in particular that really gave a strong impression of how the earth moved, produced by a team at Caltech. They’re available for download from http://shakemovie.caltech.edu/ and I’ve uploaded the version above to YouTube since the original files are a bit inconvenient as .mpg’s.
It’s fascinating to match up the animation with our experience during the quake. You can see Simi Valley on the left side of the screen, and watch as the ground waves go past. We felt a strong jolt, followed by some strong but low frequency side to side movement. In the video you can see the waves flowing past us, amplified by the low valley, running much less coherently in the mountains that surround us. The map of peak ground acceleration shows how little the hills shake compared to the lowlands.
What really impresses me about Caltech’s work is that this isn’t a one-off for this earthquake, they seem to have a production line going for all major quakes in southern California. They aim to get the animations online within 45 minutes of any local one with a magnitude more than 3.5. I’m betting we see a lot more of them next time we get hit, and I’d love to see them duplicate it into the Bay Area and other places with active seismology. They don’t have any information up about the technology they’re using, but I’ll be keeping an eye on their site to learn more once they do publish something on it.