Log In

Seismic Hazards – LA County (from State of CA)

Zones of required investigation for possible earthquake faulting, landslides, and liquefaction are delineated and distributed to cities, counties, and state construction agencies to help identify where higher building standards may be necessary for safe development.

Seismic Hazard Regulatory Hazard Zones
Earthquake Fault Zone prevent
buildings for human occupancy from
being constructed upon active
faults. Statutes require that cities
and counties use these zones as part
of their construction permitting
process.
Liquefaction Zone identify
where the stability of foundation
soils must be investigated, and
countermeasures undertaken in the
design and construction of buildings
for human occupancy. Statutes
require that cities and counties use
these zones as part of their
construction permitting process.
Landslide Zone identify where
the stability of hillslopes must be
evaluated, and countermeasures
undertaken in the design and
construction of buildings for human
occupancy. Statutes require that
cities and counties use these zones
as part of their construction
permitting process.

Source: California Geological Survey; last update: varies by base map.

Download not currently available:
Seismic – Fault Trace
Seismic – Fault Zone
Seismic – Landslide
Seismic – Liquefaction
We’ve provided a direct link to download the data from the State of CA.

Seismic – Fault Trace – Data download, click here.  (this one is so old it has a .e00 file format!!)

Seismic – Fault Zone – Data download by quad sheet, click here.

Seismic – Landslide and Liquefaction – Data download by quad sheet, click here.

Related Links:

 

 

Using GIS Data on this site

GIS Data downloaded from this site generally requires GIS software to view. Click here for a list of GIS Data Viewers

GIS data available on this website is provided AS IS - please read the GIS Data Portal Terms of Use

Data Field Descriptions

No real field descriptions with this information.  Just line and polygon outlines.


GIS Source Information
Database Name: eGIS_Hazards
Feature Class Name: listed above
Feature Dataset Name (if applicable):
Reference Date:
Accuracy: Other
Update Frequency: Unknown
Access Constraints:None

Contact Information
Dan Hoffman
GIS Specialist
Los Angeles County
Dept. of Regional Planning


Los Angeles, CA 90012
dhoffman@planning.lacounty.gov
213-974-8286

2 comments to Seismic Hazards – LA County (from State of CA)

  • Bakerceg: We removed the reference and just kept the links.

  • bakerceg

    Your statement “The layers for all seismic hazards except liquefaction are based on California Geological Survey (CGS) Seismic Hazard Zone Maps, 1997-2005. Liquefaction data is derived from CGS Alquist-Priolo maps, 1974-2007.” doesn’t make sense. The only features on an Alquist-Priolo (Special Studies Zones, now Earthquake Fault Zones) Map are mapped traces of active faults and the zones delineated along them, not liquefaction zones. The Seismic Hazard Zones Maps should be the source of the liquefaction zones; however, they are NOT the source of fault traces or fault zones. Jim Baker

Leave a Reply