California Earthquake Could Be the Next Katrina

[amber]

Originally Posted by David

I don't know what happened to BART. I don't think there was any damage to the system. I don't recall hearing anything in the news about damage to it.

One small portion of the Nimitz Freeway collapsed -- top level onto bottom level -- owing to a phenomenon called site response. It's a term used to describe the effect shallow layers of soft sediment have on seismic waves. Ground motion is a lot more violent in soft, uncompacted sediments because seismic wave amplitudes actually increase when they reach those points, & they become trapped in the "wiggle." Think of groundfill soil that liquifies during a quake, which is especially dangerous.

Seismologists actually use a great example: imagine you have a pan of Jell-O, another pan of brownie batter & yet another pan of overcooked brownies. If you bang the side of each dish, which substance is going to shake more? The Jell-O first, by far, & then the brownie batter & finally the hard-as-rock brownies.

The small section of the Nimitz that collapsed is sitting on top of estuarine mud, while the freeway sections to the north & to the south of that are built on denser, harder alluvium. The places in Oakland with the least damage were generally built atop harder rock: sandstone, shale, limestone, etc.

Most of the Marina District on the Peninsula is also on mud, which is why it liquifies in earthquakes. It's bad news.

Brilliant. Thanks David.
Oh, I also live in an old wooden house that was made into apartments. We're going down, but luckily I'm on the top floor. Unluckily, there's a giant tree in my courtyard about 15 feet from my apt. Unluckily, I'm pretty sure this place is a fire trap. Luckily, I'm sure we're on something solid. Unluckily, I just checked a "peak ground accelaration percentage" map, and it appears I'm in the 70-80% ground acceleration zone.
Hmmm, I think I'll stop thinking about this now.
On another note, when I was looking this up, I found a gay and lesbian ice hockey league, the Oakland Earthquakes. From their site:

"Q: I'm not gay! What do I do now? I still want to play with you guys!
A: Being attracted to the opposite sex can be hard in today's world but luckily it is becoming more and more accepted. Chin up little heterosexual. Being straight is not a choice and we understand that. That's why we here at the Earthquakes accept all sexual orientations on our team. Come join us and be a part of our family - we'll welcome you in, even if the rest of society doesn't."