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Now building codes.
A building is built to withstand some shaking - not some magnitude. Any building can withstand a M8 if it is far enough away.
The code says that a building should not collapse in the worst shaking that has a 10% chance of happening in 50 years. 1/4
A building is built to withstand some shaking - not some magnitude. Any building can withstand a M8 if it is far enough away.
The code says that a building should not collapse in the worst shaking that has a 10% chance of happening in 50 years. 1/4
There is not one standard for all of California. At every location, @USGS calculates what is the expected shaking from known faults and a new building is built for that. A building in San Bernardino has to be stronger than a building in Orange County. 2/4 
The building code doesn't try to prevent damage. It just says the building shouldn't kill people. Building "to code" means the weakest building that will not collapse in the pretty bad quake. It gives us disposable buildings. 3/4
I'm seeing lots of confusion between earthquake magnitude, shaking and damage. Here's a simple outline:
Earthquakes happen because of slip across a fault that produces shaking as one of its effects. The total energy released is the magnitude. One number per quake. 1/7
Earthquakes happen because of slip across a fault that produces shaking as one of its effects. The total energy released is the magnitude. One number per quake. 1/7
Every point on the quake's fault produces energy, so the bigger the fault, the bigger the quake. Magnitude depends on the fault length, width, and the amount of slip. Both width and slip tend to scale with length, so you can guess the length of the fault from the magnitude. 2/7
The fault starts to move at a hypocenter and then moves down the fault at ~3 km/sec. A 3 km fault (M~5) breaks in 1 sec. A 300 km fault (~M8) takes 100 sec to break. So the duration of the quake depends on magnitude. Bigger quakes last longer and affect a larger area. 3/7
