On Thursday, September 23, the regulatory Alquist-Priolo Earthquake Fault Zone maps revealed where local governments must require site-specific geologic and engineering studies before developments are built to ensure hazards are identified and avoided.
The Alquist-Priolo Act was passed into law after the 1971 magnitude 6.6 San Fernando earthquake that damaged many buildings.
"Since the first Earthquake Fault Zone maps were issued in 1974, there have been about 30 earthquakes associated with surface faulting in California," Steve Bohlen, state geologist of California told ABC 10News. "For the most part, the surface displacement is relatively minor. But there have been seven earthquakes that produced offsets greater than a foot -- more than enough to break the foundation of a building, which could cause a collapse."
Two maps were prepared for the Rose Canyon Fault where it approaches Coronado Island and runs through the San Diego area to the northwest and back offshore near La Jolla.
According to ABC 10News, the new maps were finalized after being reviewed by local government entities, the public, and the state mining and geology board.