"Your threat level is Motley Crue but could rise to above Kiss at any time."
The problem is the fact that most of the Bay Area is built upon a foundation of soft mud that, during an earthquake, is prone to something frighteningly referred to as liquefaction, which is exactly what it sounds like. Estimates say that a quake in the range of a 7.8 on the Richter scale (which is right in the range of what we'd expect -- the 1906 quake was an 8.0) would topple 1,500 buildings and badly damage another 300,000. The government has just started rushing against time to brace the Golden Gate Bridge after reports showed a quake would cause it to utterly collapse.
Like this, but with a billion-dollar special effects budget.
But what's really standing between San Francisco and avoiding total annihilation is money. With a $25.4 billion budget deficit, the California government wants property owners to retrofit their own damn buildings if they're so scared of earthquakes, a cost that no average person can afford, forcing them into a much cheaper but less effective form of earthquake insurance -- prayer. Never mind that the cost of earthquake-proofing San Francisco would only be around $260 million, compared to the estimated cost of rebuilding after a quake -- $200 billion. But, hey, we're not economists.