Previously unmapped earthquake faults ruptured during the Aug. 24 magnitude-6.0 South Napa earthquake, surprising both scientists and homeowners. In the Browns Valley neighborhood, one section of the fault cracked through homes, splitting foundations and damaging some houses so severely that they were evacuated. The California Geological Survey is studying the possible fault strands and is working on a regulatory map.
A magnitude-7.8 earthquake on the San Andreas fault could cut off Los Angeles from all three major aqueducts that supply 88% of its water. Water agencies in the San Francisco area have made seismic upgrades to the Hetch Hetchy and Mokelumne aqueducts.
Developers of property within the state¿s finalized Sierra Madre earthquake fault zone generally will have to prove new construction will not be on top of an earthquake fault.
When Los Angeles officials begin an ambitious effort to comb the city and check which buildings might be at risk in a major earthquake, they will also examine how efficiently the structures use water and electricity, Mayor Eric Garcetti said Monday.
Garcetti proposes seismic ratings of office buildings and apartments and posting the information publicly. He also wants a mandatory retrofit program.
The quakes appear to have been on the Puente Hills fault, which runs from the San Gabriel Valley to downtown L.A. and caused the 1987 Whittier Narrows quake.
Although the 6:25 a.m. quake beneath the Santa Monica Mountains caused no damage, it showed there is still much to be learned and served as a warning for residents to be prepared.
L.A. building owners can pass on only 50% of the costs of seismic upgrades, but Councilman Bernard Park wants to hike that to 100%.
Legislation by state Sen. Ted Lieu aims to close a loophole that allows building on or near earthquake faults that haven't been zoned by the state.