A Santa Monica Fault Study Zone has not yet been mapped by the California Geological Survey (CGS). In July 2015, Los Angeles Mayor Eric Garcetti released a statement regarding a new seismic safety measure. The mayor stated:
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“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). This measure puts L.A. ahead of the state in ensuring new buildings are not built above active fault lines in the City of Los Angeles.
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LADBS’s Preliminary Fault Rupture Study Areas are areas 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.”
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The LADBS released a special instructions memorandum concurrent with the mayor’s statement stating that the PFRSAs will act as temporary Earthquake Fault Zones until the CGS releases the boundaries of the permanent Alquist-Priolo Earthquake Fault Zones.
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References:
https://www.ladbsservices2.lacity.org/OnlineServices/PermitReport/DisplayPDF?path=LAPFRSA.pdf
The three new Preliminary Fault Rupture Study Areas (PFRSAs) released by the Los Angeles Department of Building and Safety (LADBS) include zones for the Hollywood-Raymond fault, the Palos Verdes fault, and the Santa Monica fault. A map of the zones is shown above. To view the new PFRSAs using NavigateLA, click here.
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Since the CGS has not mapped the limits of the Santa Monica Fault Study Zone, the below image is an approximation of the fault study area limits. The areas mapped in yellow represent the zone 500 feet away from the published United States Geological Survey (USGS) fault traces.
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*This image is for illustration purposes only and does not reflect the actual published fault study zone boundaries.
The LADBS’s PFRSAs do not include any zones within the Santa Monica city limits. As such, the City of Santa Monica has published a separate Geologic Hazards map showing the city’s interpretation of fault traces and a Fault Hazard Management Zone. The image above shows The City of Los Angeles’s Santa Monica fault PFRSA overlain by the City of Santa Monica’s Geologic Hazards Map. Any new development proposed within the PFRSA or the Fault Hazard Management Zone requires a fault investigation.
