Dire SF Earthquake Prediction (David?)

[amber]

Originally Posted by David

I guess there's a lot of glass in the financial district.
It's interesting to read up on the building codes & how they've been revised over the decades. After all, modeling is only modeling. In general, the bigger the quake, the longer the duration of shaking. That's what brings down structures built or refitted to code. The deadliest damage in the 1989 quake occurred on the Nimitz Freeway: the part that collapsed was built on San Francisco Bay mud rather than rock. Mud & softer alluvial soil jiggle like Jell-O in an earthquake, amplifying the intensity of the shaking.

The Loma Prieta quake was a moment magnitude 6.9; the shaking lasted about 15 seconds. Imagine a much larger quake -- say, an M7.8, about the size of the 1906 quake. Shaking lasted about a full minute in San Francisco. Buildings that can withstand 15 seconds might not be able to withstand shaking that lasts for a full minute or more.

Luckily, quakes larger than that are extremely unlikely on any portion of the San Andreas fault zone. There just isn't enough locked fault to unzip.
Southern CA is overdue, too. The best you can do is to learn what kind of soil or rock your residence or your workplace is built on. Site response is the name of the game these days. I live on a 1,000-foot mountain or hillside, made of solid rock. When a quake hits nearby, all I feel usually is a single wrenching jolt, followed by stillness.

Okay, the other night I was watching "Birth of a City" about SF - and I thought I heard them say something like: "And so they filled in ....[something something] and the financial district was born!"