Mayor Eric Garcetti announced a new seismic safety measure aimed to help protect lives and property in the event of an earthquake. The Los Angeles Department of Building & Safety (LADBS) has established three new “Preliminary Fault Rupture Study Areas” for several fault lines within the city that have not yet been mapped by the California Geological Survey (CGS).

LADBS’s Preliminary Fault Rupture Study Areas outlines where active faults may exist and present a potential for ground rupture to occur during a local earthquake. If a proposed development is found to be in a Preliminary Fault Rupture Study Area, geologic investigations to determine the presence or absence of an active fault will be required before building permits are issued by LADBS. The Preliminary Fault Rupture Study Areas will not affect existing buildings, only new developments.

State geological surveys are tasked by state law to establish earthquake fault zones in which geologic investigations are required prior to permitting new development. The 1972 Alquist-Priolo Act prohibits the construction of most structures for human occupancy over active faults. However, the state has not established earthquake fault zones for all active faults in California, including some known faults in Los Angeles.

The city’s Preliminary Fault Rupture Study Areas are intended to act as temporary measures until CGS establishes permanent Alquist-Priolo zones.

The mapped zones are available online at navigatela.lacity.org.