As a Southern Californian, I have been through several earthquakes the have been in the 6.0-6.5 Richter scale range. On the other hand, I have never been really close to the epicenter when they happened. Some of these earthquakes caused quite a bit of damage but there was never a huge loss of life.
A lot of long time Southern Californians are pretty smug about earthquakes. They have been through some and been alright. They believe that the building codes and regulations in place are adequate to insure that any earthquake catastrophe will be limited.
The Earthquake in Chile the other day was 8.8. That's more than a thousand times more powerful than anything that has happened around here in my lifetime. There is no reason that an earthquake of that magnitude couldn't happen in Southern California. In fact, it's likely that one will, sooner or later.
Not only will a lot of people die right away in something like that but utilities and water supplies will be cut off indefinitely. There are about 25 million people in So Cal and almost no sources of naturally occurring potable water that you can drink directly from.
It'll be interesting when the big one hits.