This data set contains the Alquist-Priolo Earthquake Fault Zones as shown on the Official Alquist-Priolo Earthquake Fault Zones Maps. The dataset is comprised of polygons that form regulatory zone boundaries (Alquist-Priolo Earthquake Fault Zones). These features delineate areas where surface fault rupture previously has occurred, or where local topographic, geological, and geotechnical conditions indicate a potential for permanent ground displacements such that mitigation by avoidance as stated in Public Resources Code Section 2621.5 would be required.

Seismic hazard zone (Alquist-Priolo) for development of the Parcel Inventory dataset for the Housing Element Site Selection (HESS) Pre-Screening Tool.

These features designate the Alquist-Priolo Earthquake Fault Zones as shown on the Official Alquist-Priolo Earthquake Fault Zones Map. The data set is comprised of polygons that form regulatory zone boundaries (Alquist-Priolo Earthquake Fault Zones). These features delineate areas where surface fault rupture previously has occurred, or where local topographic, geological, and geotechnical conditions indicate a potential for permanent ground displacements such that mitigation by avoidance as stated in Public Resources Code Section 2621.5 (https://casetext.com/statute/california-codes/california-public-resources-code/division-2-geology-mines-and-mining/chapter-75-earthquake-fault-zoning/section-26215-generally) would be required.

This data will assist cities and counties in fulfilling their responsibility to prohibit the location of developments and structures for human occupancy across the trace of active faults as required by the Alquist-Priolo Earthquake Fault Zoning Act (Public Resources Code, Division 2, Chapter 7.5, Sections 2621-2630). Local governments can withhold development permits until geologic investigations are conducted for specific sites and mitigation measures are incorporated into development plans. Sellers of property use the maps to check the location of their specific site and, if applicable, disclose to the buyer that the property lies within an earthquake fault zone as required by the Alquist-Priolo Earthquake Fault Zoning Act (PRC Section 2621.9).

For information regarding the scope and recommended methods to be used in conducting the required site investigations, see California Geological Survey (CGS) Special Publication 42, Fault-Rupture Hazard Zones in California (https://www.conservation.ca.gov/cgs/Documents/Publications/Special-Publications/SP_042.pdf).

This data was downloaded from https://maps.conservation.ca.gov/cgs/informationwarehouse/index.html.

Analysis of ‘CGS Seismic Hazards Program: Fault Traces’ provided by Analyst-2 (analyst-2.ai), based on source dataset retrieved from https://catalog.data.gov/dataset/eaa3b470-deae-4221-8124-ded323918996 on 12 February 2022.

--- Dataset description provided by original source is as follows ---

This data set contains the Alquist-Priolo Earthquake Fault Zones and fault traces as shown on the Official Alquist-Priolo Earthquake Fault Zones Map of the {quadName} quadrangle. The dataset is comprised of polygons that form regulatory zone boundaries (Alquist-Priolo Earthquake Fault Zones), lines that show identified fault traces, and label points and leaderlines for fault trace annotation. These features delineate areas where surface fault rupture previously has occurred, or where local topographic, geological, and geotechnical conditions indicate a potential for permanent ground displacements such that mitigation by avoidance as stated in Public Resources Code Section 2621.5 would be required.

--- Original source retains full ownership of the source dataset ---

This data set contains the Alquist-Priolo Earthquake Fault Zones as shown on the Official Alquist-Priolo Earthquake Fault Zones Maps. The dataset is comprised of polygons that form regulatory zone boundaries (Alquist-Priolo Earthquake Fault Zones). These features delineate areas where surface fault rupture previously has occurred, or where local topographic, geological, and geotechnical conditions indicate a potential for permanent ground displacements such that mitigation by avoidance as stated in Public Resources Code Section 2621.5 would be required.

This data set contains the Alquist-Priolo Earthquake Fault Zones as shown on the Official Alquist-Priolo Earthquake Fault Zones Maps. The dataset is comprised of polygons that form regulatory zone boundaries (Alquist-Priolo Earthquake Fault Zones). These features delineate areas where surface fault rupture previously has occurred, or where local topographic, geological, and geotechnical conditions indicate a potential for permanent ground displacements such that mitigation by avoidance as stated in Public Resources Code Section 2621.5 would be required.

The Alquist-Priolo Earthquake Fault Zoning (AP) Act was passed into law following the February 9, 1971 San Fernando earthquake. This layer maps the active fault zones identified by the Act. The intent of the Act is to ensure public safety by prohibiting the siting of most structures for human occupancy across traces of active faults that constitute a potential hazard to structures from surface faulting or fault creep.

Alquist-Priolo Earthquake Fault Zoning Act (1972) and the Seismic Hazards Mapping Act (1990) direct the State Geologist to delineate regulatory "Zones of Required Investigation" to reduce the threat to public health and safety and to minimize the loss of life and property posed by earthquake-triggered ground failures. Cities and counties affected by the zones must regulate certain development "projects" within them. These Acts also require sellers of real property (and their agents) within a mapped hazard zone to disclose at the time of sale that the property lies within such a zone.

NOTE: Fault Evaluation Reports are available for those areas covered by a Regulatory Map however there are reports available for areas outside the Regulatory map boundary. For a complete set of maps available for purchase on CD please contact the CGS Library.

Alquist-Priolo Earthquake Fault Zoning Act (1972) and the Seismic Hazards Mapping Act (1990) direct the State Geologist to delineate regulatory "Zones of Required Investigation" to reduce the threat to public health and safety and to minimize the loss of life and property posed by earthquake-triggered ground failures. Cities and counties affected by the zones must regulate certain development "projects" within them. These Acts also require sellers of real property (and their agents) within a mapped hazard zone to disclose at the time of sale that the property lies within such a zone. NOTE: Fault Evaluation Reports are available for those areas covered by a Regulatory Map however there are reports available for areas outside the Regulatory map boundary. For a complete set of maps available for purchase on CD please contact the CGS Library.

EARTHQUAKE FAULT ZONE OF REQUIRED INVESTIGATION These zones are delineated to assist cities and counties in fulfilling their responsibilities for protecting the public safety from the effects of earthquake fault rupture as required by the Alquist-Priolo Earthquake Fault Zoning Act (Public Resources Code Sections 2623 et seq). For a general description of the Alquist-Priolo Earthquake Fault Zoning Act and regulations, downloadable official zones and related information, please refer to the California Geological Survey Website at (http://www.conservation.ca.gov/cgs/rghm/ap/Pages/index.aspx) FAULT TRACES Fault trace features are from the California Geological Survey 2010 Fault Map of California and show the location of the ground surface trace of faults that are categorized by age for the past 1.6 million years (previously-defined Quaternary Period). Users of this information should be aware that active faults and earthquakes are the subject of continuing research and that refinement of the interpretations given here are sure to come within a few years. California Geological Survey Bulletin 201, “An Explanatory Text to Accompany the Geologic Map of California,” published separately, contains detailed source index maps and references to all the published and unpublished reports and information used in compiling the 1975 Fault Map of California. For additional information about the 2010 version of this map go to the following (http://www.conservation.ca.gov/cgs/cgs_history/Pages/2010_geologicmap.aspx)

LIMITATIONS 1)This site is not designed for official natural hazards disclosure determination. “Official” natural hazard zones viewed on this site are of insufficient resolution to definitively determine in all cases whether an individual property lies within a earthquake fault zone for disclosure purposes pursuant to California Civil Code Section 1103 et seq.
2)This map may not show all potentially active faults, either within the earthquake fault zones or outside their boundaries. 3)Faults shown within earthquake fault zones are the basis for establishing the zone boundaries. 4)The identification of faults and the location of fault traces are based on based on available data at various scales of accuracy, and have not been field checked. Overlay of zones on other base maps can result in discordance with base map features. 5)DISCLAIMER: The State of California and the Department of Conservation make no representations or warranties regarding the accuracy of these zones or fault traces, or the data from which these zones and fault traces were derived. Neither the State nor the Department shall be liable under any circumstances for any direct, indirect, special, incidental or consequential damages with respect to any claim by any user or any third party on account of or arising from the use of this information.

Alquist-Priolo Earthquake Fault Zoning Act (1972) and the Seismic Hazards Mapping Act (1990) direct the State Geologist to delineate regulatory "Zones of Required Investigation" to reduce the threat to public health and safety and to minimize the loss of life and property posed by earthquake-triggered ground failures. Cities and counties affected by the zones must regulate certain development "projects" within them. These Acts also require sellers of real property (and their agents) within a mapped hazard zone to disclose at the time of sale that the property lies within such a zone. Click on the following link for more information on the Alquist-Priolo Earthquake Fault Zoning Act. Click on the following link for more information on the Seismic Hazards Mapping Act. NOTE: Fault Evaluation Reports are available for those areas covered by a Regulatory Map however there are reports available for areas outside the Regulatory map boundary. For a complete set of maps available for purchase on CD please contact the CGS Library.

Analysis of ‘CGS Seismic Hazards Program: Alquist-Priolo Fault Hazard Zones’ provided by Analyst-2 (analyst-2.ai), based on source dataset retrieved from https://catalog.data.gov/dataset/8dce3aba-526f-4bb2-9d68-99e4539d80ec on 27 January 2022.

--- Dataset description provided by original source is as follows ---

This data set contains the Alquist-Priolo Earthquake Fault Zones as shown on the Official Alquist-Priolo Earthquake Fault Zones Maps. The dataset is comprised of polygons that form regulatory zone boundaries (Alquist-Priolo Earthquake Fault Zones). These features delineate areas where surface fault rupture previously has occurred, or where local topographic, geological, and geotechnical conditions indicate a potential for permanent ground displacements such that mitigation by avoidance as stated in Public Resources Code Section 2621.5 would be required.

--- Original source retains full ownership of the source dataset ---

While Long Beach is less likely than other areas of the State to experience earthquakes, all of California is at higher risk compared to the rest of the country. In an attempt to mitigate potential damages, California passed the Alquist-Priolo Earthquake Zoning Act on December 22, 1972.This pdf map visualizes inferred and known fault lines as well as Alquist-Priolo Special Studies Zones within the City of Long Beach.

description: The Alquist-Priolo Earthquake Fault Zoning Act was signed into California law on December 22, 1972 to mitigate the hazard of surface faulting to structures for human occupancy. It directs the State of California Division of Mines and Geology (now known as the California Geological Survey) to compile detailed maps of the surface traces of known active faults. These maps include both the best known location where faults cut the surface and a buffer zone around the known trace(s). (See: Wikipedia http://en.wikipedia.org/wiki/Alquist_Priolo_Special_Studies_Zone_Act).; abstract: The Q3 Flood Data are derived from the Flood Insurance Rate Maps (FIRMs) published by the Federal Emergency Management Agency (FEMA). The file is georeferenced to the earth's surface using the geographic projection and the decimal degree coordinate system. The specifications for the horizontal control of Q3 Flood Data files are consistent with those required for mapping at a scale of 1:24000.FEMA Flood maps for CaliforniaSafety, Natural HazardsFlood Hazards

Earthquake related hazards in California The Alquist-Priolo Earthquake Fault Zoning Act was signed into California law on December 22, 1972 to mitigate the hazard of surface faulting to structures for human occupancy. It directs the State of California Division of Mines and Geology (now known as the California Geological Survey) to compile detailed maps of the surface traces of known active faults. These maps include both the best known location where faults cut the surface and a buffer zone around the known trace(s). Earthquakes happen when two blocks of the Earth's crust move relative to one another. The place where the blocks meet is called a fault, and faults tend to show up as relatively straight lines on maps. Any structure built directly on top of the fault will be torn in two when the blocks move. It's not easy to build a building that can withstand this sort of movement (often several feet in a matter of seconds), so it's best to avoid building directly on top of an active fault. (See: Wikipedia http://en.wikipedia.org/wiki/Alquist_Priolo_Special_Studies_Zone_Act). IMPORTANT!: The liquefaction and earthquake induced land slide data used for this map service are NOT statewide and are limited to select locations in the San Francisco Bay Area and Southern California.

County Faults/Fault Zones (Per Riverside County General Plan 10/2003). Alquist-Priolo Earthquake Fault Zones have been designated by the California Division of Mines and Geology for the Elsinore, San Jacinto, and San Andreas fault zones in Riverside County. Within the rapidly growing county, State A-P mapping has not kept pace with development. The County of Riverside has zoned fault systems and required similar special studies prior to development. These are referred to as County Fault Zones on Figure S-2 and in the Technical Background Report. Within A-P and County Fault Zones, proposed tracts of four or more dwelling units must investigate the potential for and setback from ground rupture hazards. As there are many active faults in Riverside County, with new fault strands being continually discovered, all proposed structures designed for human occupancy should be required to investigate the potential for and setback from ground rupture. Also of concern are structures, not for human occupancy, that can cause harm if damaged by an earthquake, such as utility, communications, and transportation lifelines. The County regulates most development projects within earthquake fault zones (Figure S-2). Projects include all land divisions and most structures for human occupancy. Before a project can be permitted within an A-P Earthquake Fault Zone, County Fault Zone, or within 150 feet of any other potentially active or active fault mapped in published United States Geological Survey (USGS) or California Division of Mining and Geology (CDMG) reports, a geologic investigation must demonstrate that proposed buildings will not be constructed across active faults.Updated 2/2016 with Thermal and Indio California Geologic Survey Quads

Analysis of ‘CGS Seismic Hazards Program: Fault Traces’ provided by Analyst-2 (analyst-2.ai), based on source dataset retrieved from https://catalog.data.gov/dataset/8bb3b7b5-f8e3-4c8a-92d6-1a59e1e41adc on 12 February 2022.

--- Dataset description provided by original source is as follows ---

This data set contains the Alquist-Priolo Earthquake Fault Zones and fault traces as shown on the Official Alquist-Priolo Earthquake Fault Zones Map of the {quadName} quadrangle. The dataset is comprised of polygons that form regulatory zone boundaries (Alquist-Priolo Earthquake Fault Zones), lines that show identified fault traces, and label points and leaderlines for fault trace annotation. These features delineate areas where surface fault rupture previously has occurred, or where local topographic, geological, and geotechnical conditions indicate a potential for permanent ground displacements such that mitigation by avoidance as stated in Public Resources Code Section 2621.5 would be required.

--- Original source retains full ownership of the source dataset ---

Analysis of ‘CGS Information Warehouse: Regulatory Maps’ provided by Analyst-2 (analyst-2.ai), based on source dataset retrieved from https://catalog.data.gov/dataset/6c006a45-901c-4ff0-8c60-34111b3f28a7 on 12 February 2022.

--- Dataset description provided by original source is as follows ---

Alquist-Priolo Earthquake Fault Zoning Act (1972) and the Seismic Hazards Mapping Act (1990) direct the State Geologist to delineate regulatory "Zones of Required Investigation" to reduce the threat to public health and safety and to minimize the loss of life and property posed by earthquake-triggered ground failures. Cities and counties affected by the zones must regulate certain development "projects" within them. These Acts also require sellers of real property (and their agents) within a mapped hazard zone to disclose at the time of sale that the property lies within such a zone.

NOTE: Fault Evaluation Reports are available for those areas covered by a Regulatory Map however there are reports available for areas outside the Regulatory map boundary. For a complete set of maps available for purchase on CD please contact the CGS Library.

--- Original source retains full ownership of the source dataset ---

Alquist-Priolo Fault Zones from the California Geological Survey

This dataset includes the data used to develop Map 10 for the Connect SoCal 2024 Equity Analysis Technical Report, adopted on April 4, 2024. The dataset includes binary indicators for seven climate hazard geographies in the SCAG region based on the latest available geographic information. The nine layers were overlaid using the ArcGIS union tool with a minimum of one and a maximum of six overlapping layers in the region. The climate hazard layers include: flooding, landslides, sea-level rise, extreme heat, wildfires, drought, and earthquake hazard zones. This dataset was prepared to share more information from the maps in Connect SoCal 2024 Equity Analysis Technical Report. To reduce the loading time for the complex geometry of this layer, the vertices were simplified with a tolerance of 1 foot. For more details on the methodology, please see the methodology section(s) of the Equity Analysis Technical Report: https://scag.ca.gov/sites/main/files/file-attachments/23-2987-tr-equity-analysis-final-040424.pdf?1712261887 For more details about SCAG's models, or to request model data, please see SCAG's website: https://scag.ca.gov/data-services-requestsClimate Hazard Source Details:Flood: 100-year and 500-year flood areas from Federal Emergency Management Agency (FEMA); 2017Landslide: Landslide zones from California Geological Survey (CGS), California Department of Conservation; California Department of Conservation, California Geological Survey Geologic Maps, Accessed June 2023Sea-level rise: areas vulnerable to 1 meter of sea-level rise from the Coastal Storm Modeling System (CoSMoS), U.S. Geological Survey (USGS); Coastal Storm Modeling System (CoSMoS) for Southern California, v3.0, Phase 2, 2018, USGSWildfire: Local Responsibility Areas and State Responsibility Areas that are moderate, high, and very high risk of wildfires from CalFire; Fire Hazard Severity Zones Local Responsibility Areas Maps, 2007/2008, Wildland Urban Interface, 2020, CAL FIIREExtreme heat: areas that are projected to experience more than two heat health events from 2031 to 2050 from the California Heat Assessment Tool, California Natural Resources Agency, Accessed June 2023Drought: areas that experienced severe, extreme, or exceptional drought during September 2014 from U.S. Drought Monitor, Accessed June 2023Earthquake: Alquist-Priolo Earthquake Fault Zones from the California Geological Survey (CGS), California Department of ConservationSubstandard Housing: Housing units without plumbing facilities, U.S. Census Bureau American Communities Survey 5-year estimates 2017-2021

The following five natural hazards were used to analyze the hazard exposure of parcels in the San Francisco Bay Region:

Alquist-Priolo Fault Zones

  Publication_Date: 2018
  Publisher: Department of Conservation, California Geological Survey
  https://maps.conservation.ca.gov/cgs/metadata/SHP_Fault_Zones.html


CGS Earthquake-Induced Landslide Study Zones
  Publication_Date: 2005Publisher: Department of Conservation, California Geological Surveyhttps://maps.conservation.ca.gov/cgs/informationwarehouse/regulatorymaps/
CGS Liquefaction Study Zones

  Publication_Date: 2017
  Publisher: Seismic Hazards Program, California Geological Survey, California Department of Conservation
  https://maps.conservation.ca.gov/cgs/metadata/SHP_Liquefaction_Zones.html


CGS Deep-Seated Landslide Susceptibility
  Publication_Date: 2011Publisher: Department of Conservation, California Geological Surveyhttps://maps.conservation.ca.gov/cgs/metadata/MS58_metadata.pdfUSGS Liquefaction Susceptibility Zones

  Publication_Date: 2005
  Publisher: U.S. Geological Survey
  https://pubs.usgs.gov/of/2000/of00-444/



Parcels are marked as being susceptible to a hazard if any portion of the parcel is affected by it. The reason for this is the potential effects of future hazard events cannot be precisely delineated. This means all polygons representing a given hazard or severity level are estimates, with boundaries between values being fuzzy in real world conditions.-----------------------------------------The Association of Bay Area Governments' Resilience Program makes 

this data available, along with other hazard data, in an effort to provide a one-stop-shop for local governments to access data for hazard/resilience planning. More information on the program and its work can be accessed from the Resilience Program information page.