"For decades Southern Californians have worked to reduce their vulnerability to earthquakes. The 1994 North-ridge shock, damaging as it was, proved the value of these efforts. Yet, much more needs to be done. Scientists are preparing new maps of the earthquake shaking hazard in Southern California. Such maps help make living in the region safer by focusing efforts to strengthen existing structures and by providing guidance in building new structures."
U.S. Geological Survey: http://www.usgs.gov/