California Department of Conservation (DOC), California Geological Survey (CGS)
Alquist-Priolo Earthquake Fault Evaluation and Zoning Program
Metadata for Alquist-Priolo (AP) Earthquake Fault Zones (EFZ)
Earthquake Fault Zone Map web service
TABLE OF CONTENTS
Identification Information
Data Quality Information
Spatial Data Organization Information
Spatial Reference Information
Entity and Attribute Information
Distribution Information
Metadata Reference Information
IDENTIFICATION INFORMATION
Citation:
Citation_Information
Publication_Date: 2018
Publication_Time: Unknown
Title: GIS files of Official Maps of Alquist-Priolo Earthquake Fault Zones
Series_Information:
Official Maps of Earthquake Fault Zones
Publication_Information:
Publication_Place: Sacramento, CA
Publisher: Department of Conservation, California Geological Survey
Suggested_Citation:
California Geological Survey. 2018, Official Maps of Earthquake Fault Zones: Web Service of Official Maps of Alquist-Priolo Earthquake Fault Zones, Sacramento, CA. Department of Conservation, California Geological Survey. http://maps.conservation.ca.gov/cgs/informationwarehouse/. Accessed [Day] [Month] [Year]
Description
Abstract: This data set contains the Alquist-Priolo Earthquake Fault Zones and fault traces as shown on the Official Alquist-Priolo Earthquake Fault Zones Map. 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.
Purpose: This map 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 Special Publication 42, Fault-Rupture Hazard Zones in California.
Supplemental_Information: Supplemental_Information: Faults shown are the basis for establishing the boundaries of the Earthquake Fault Zones. This database may not show all faults that have the potential for surface fault rupture, either within the Earthquake Fault Zones or outside their boundaries. The identification and location of these faults are based on the best available data. However, the quality of data used is varied. Fault traces have been drawn as accurately as possible at the map scale (1:24,000).
These data do not include Seismic Hazard Zones, if any, that may exist in this area. Please refer to the latest Official Maps of Seismic Hazard Zones for disclosures and other actions that are required by the Seismic Hazards Mapping Act. For more information on this subject see California Geological Survey Special Publication 117A.
Fault information on this map is not sufficient to serve as a substitute for the geologic site investigations required under Chapter 7.5 of Division 2 of the California Public Resources Code.
The original mapping was conducted on an earlier version of the USGS 7.5-minute topographic quadrangle map, utilizing California State Plane (Lambert Conformal Conic) projection (feet) and North American Datum of 1927. These data are currently maintained and distributed in a California Albers projection (meters) and North American Datum of 1983 [EPSG:3310]. It should be noted that the same geographic coordinate (e.g., -120.00 degrees longitude; 39.00 degrees latitude) will fall in a different location on the earth's surface when datums are changed.
Time_Period_of_Content
Time_Period_Information
Single_Date/Time
Calendar_Date: 2018-01-11
Currentness_Reference: 2018
Status Progress: Complete
Maintenance_and_Update_Frequency: Unknown
Spatial_Domain
Bounding_Coordinates
West_Bounding_Coordinate: -122.37500809
East_Bounding_Coordinate: -122.24999808
North_Bounding_Coordinate: 38.3750030063
South_Bounding_Coordinate: 38.2500019975
Keywords
Theme
Theme_Keyword_Thesaurus: None
Theme_Keyword: Earthquake Fault Zone Map
Theme_Keyword: earthquake hazard identification and mitigation
Theme_Keyword: surface fault rupture
Theme_Keyword: active fault
Theme_Keyword: fault map
Theme_Keyword: Alquist-Priolo
Place
Place_Keyword_Thesaurus: None
Place_Keyword: California
Place_Keyword: USA
Access_Constraints: Because digital data are easily altered, cities, counties, and others who use this file in their permit review and approval processes, or for other actions mandated by law (e.g., real estate disclosure at time of transfer) are advised to obtain the file directly from the Department of Conservation, California Geological Survey.
Use_Constraints: LICENSE AGREEMENT: (c) 2018 California Department of Conservation, California Geological Survey. All rights reserved. No part of these data may be reproduced, transmitted, or distributed in any form or by any means, electronic or mechanical for any purpose, without the express written permission of the California Geological Survey except under the following conditions: 1) Personal use; 2) For publication in a report, in unmodified form, cite on figure or in text as "Reproduced with permission, California Geological Survey, Official Web Serivce of Alquist-Priolo Earthquake Fault Zones (2018)"; and (3) for publication in a report in modified form; cite on figure or in text as "Modified from California Geological Survey, Official Web Service of Alquist-Priolo Earthquake Fault Zones (2018)".
Point_of_Contact
Contact_Information
Contact_Organization: California Geological Survey, Seismic Hazards Program
Contact_Person_Primary
Contact_Person: Senior Engineering Geologist, Earthquake Fault Zoning Unit
Contact_Position: Project Manager
Contact_Address
Address_Type: mailing and physical address
Address: 801 K Street, MS 12-31
City: Sacramento
State: California
Postal_Code: 95814-3532
Country: USA
Contact_Voice_Telephone: (916) 322-1019
Contact_Facsimile_Telephone: (916) 445-3334
Contact_Electronic_Mail_Address: SHMP@conservation.ca.gov
Online_Source: http://maps.conservation.ca.gov/cgs/informationwarehouse/
DATA QUALITY INFORMATION
Attribute_Accuracy:
Attribute_Accuracy_Report: Prior to 2016 digital GIS files delivered did not contain any entity attributes other than a unique identifier. As of 2016 the format of the digital GIS files has been changed and there are now four feature classes, each with associated attributes. For the most part, the attribute values were automatically generated and populated via Python scripts. The date values in FAULT_ZONE.RELEASED and FAULT_ZONE.PREV_DATES were verified against Table 3, Official Maps of Earthquake Fault Zones issues 1974 through August 2007, in Special Publication 42, Interim Revision 2007, Fault-Rupture Hazard Zones in California.
Quantitative_Attribute_Accuracy_Assessment:
Attribute_Accuracy_Explanation: Areas where historic occurrences of earthquake surface fault rupture, or where geomorphic, paleo-seismic, or other evidence of surface or near-surface fault rupture in Holocene time has occurred such that mitigation by avoidance would be required for structures for human occupancy.
Logical_Consistency_Report: The following topological tests and corrections were performed on the entire, statewide feature classes. Therefore, the issues noted and corrections made may or may not be applicable in any one individual quad tile of data.
FAULT_ZONE--Geometry validation was performed and some digitizing artifacts such as kickbacks or kinks were deleted. Topological checks performed indicate that there are occurrences of small overlaps and gaps between the zones along the 7.5 topo quad boundary which have not been corrected. The median size of the overlaps for the statewide dataset is about 12 square meters.
FAULT_TRACEGeometry validation and topological checks were performed and duplicate trace segments and near-duplicate trace segments were deleted. Any multipart geometries were expanded into their respective components and kinks/kickbacks were corrected. This feature class contains occurrences of unbroken intersecting geometry, (i.e. fault traces that overlap but the overlapping traces do not share a vertex/node at the point of intersection), which have not been corrected.
FAULT_LABELGeometry validation was completed and duplicate point features were deleted. In addition, features with null values in the TEXT field were also deleted.
FAULT_LEADERLINEGeometry validation was completed and corner tic marks and duplicate leaderlines were deleted.
Completeness_Report: The dataset contains Alquist-Priolo Earthquake Fault Zones and faults as shown on the 2018 Official Map of Alquist-Priolo Earthquake Fault Zones. The topographic base map, which was included on the published map, is not included.
Positional_Accuracy:
Horizontal_Positional_Accuracy
Horizontal_Positional_Accuracy_Report: No systematic control surveys have been conducted to characterize the positional accuracy of the fault traces and earthquake fault zones. The mapping of fault traces and earthquake fault zone boundaries began in the early 1970s and has continued into the present. The processes used to generate these data span a wide range of techniques from hand drawn maps on 7.5 topographic sheets to heads up digitizing on LiDAR derived shaded relief base maps. The data have been interpreted and mapped as accurately as possible given the type of source data, and the time, staff and technology available at the time of mapping. More detailed information on mapping processes and base maps used may be available in the Fault Evaluation Report or for older maps, in the references used to compile the fault data.
Lineage:
Process_Step
Process_Description: For maps released from 1974 1995 the following processes were completed to convert the clear film overlays into digital format.
The original hardcopy maps (clear film overlays) used to reproduce Official Maps of Earthquake Fault Zones were the basis for developing the original GIS files. Each hardcopy map was scanned at full scale using an Anatech large-format scanner. The scanned image was translated to cit file format, geo-referenced (California State Plane Coordinate System (feet), North American Datum 1927), and digitized using Microstation v5.0 software to create vector files in dgn format. The digital files were printed at 1:24,000 scale and compared with the original clear-film overlay for completeness and accuracy. Digital files were then converted to dxf format, using individual layers to display specific line-styles as follows:
Layer 1: Corner registration tics for individual quadrangle map and most text data
Layer 3: Corner registration tics for oversized quadrangle maps (not present for most maps)
Layer 7: EFZ boundary polygons
Layer 8: Solid lines (accurately located fault traces)
Layer 9: Long dashed lines (approximately located fault traces)
Layer 10: Short-dashed lines (inferred fault traces)
Layer 11: Dotted lines (concealed fault traces)
Layer 12: Thin dashed and dotted lines (aerial photo lineament)
Process_Step
Process_Description: In 2016 CGS updated the existing digital GIS data to meet the following goals: 1) a consistent projection and datum for all quadrangles, 2) uniform attribution, and 3) updated metadata. This process step included all GIS data released prior to July 1, 2016.
Four ArcSDE feature classes and the necessary supporting domain tables were defined and created in an ArcGIS 10.3 enterprise geodatabase. The individual shapefiles for each quadrangle were then processed using Python scripts to 1) reproject from California State Plane Zone (feet), NAD 27 to California Albers (meters), NAD 83, 2) add attributes as needed depending on the target feature class, and 3) load the reprojected, attributed data into the appropriate ArcSDE enterprise feature class. Forty three of the 556 quadrangles were loaded using FME Workbench due to data that would not load via Python script or to deal with formatting differences.
The data layers previously created were loaded to the four feature classes as follows:
Layers 1&3 FAULT_LEADERLINE
Layer 7 FAULT_ZONE
Layers 8-12, polyline geometry FAULT_TRACE
Layers 8-12, text annotation FAULT_LABEL
Once loaded into the enterprise feature classes, QA/QC procedures were run to identify any geometry errors and standardize attributes. See Logical_Consistency_Report. For the FAULT_TRACES feature, the FAULT_NAME and FAULT_ZONE fields were updated by CGS staff by comparing the FAULT_TRACE faults with the CGS Quaternary Fault & Fold database. Where fault traces matched between the two databases, the fault name and fault zone name values from the Quaternary Fault & Fold database were copied to FAULT_TRACE features. Data values for FAULT_NAME and FAULT_ZONE were then updated to use proper case and faults previously named unnamed were updated to Null. In addition, inconsistent naming styles for some traces were standardized.
When QA/QC and all updates were complete, Python scripts were used to extract the data from the enterprise ArcSDE feature classes by quad tile, generating potentially four shapefiles per quad. Metadata templates were created and Python scripts used to generate & customize the metadata for each quad. The updated GIS data and metadata for each quad were bundled and zipped via Python scripts and then posted to CGSs Information Warehouse web site.
SPATIAL DATA ORGANIZATION INFORMATION
Direct_Spatial_Reference_Method: Vector
SPATIAL REFERENCE INFORMATION
Horizontal_Coordinate_System_Definition:
Grid_Coordinate_System:
North American Datum 1983
California Albers (meters)
Standard_Parallel 1: 34.0
Standard_Parallel 2: 40.5
Longitude_of_Central_Meridian: -120.0
Latitude_of_Projection_Origin: 0.0
False_Easting: 0.0
False_Northing: -4000000.0
Planar_Coordinate_Information:
Linear_Distance_Units: meter
Geodetic_Model Horizontal_Datum_Name: North American Datum of 1983
Ellipsoid_Name: GRS 80
Reference_System_Identifier:
EPSG 3310
ENTITY AND ATTRIBUTE INFORMATION
Overview_Description:
Entity_and_Attribute_Overview: Digital GIS files are provided as ESRI shape files. The GIS files of AP EFZ maps are current as of 2018-01-11. Please check the CGS Information Warehouse at http://maps.conservation.ca.gov/cgs/informationwarehouse/ for current information on new and revised EFZ maps.
FAULT_ZONE: EFZ boundary polygons
Attribute Fields:
QUAD_NAME: USGS 7.5 minute quadrangle official name
MAP_RELEASED: Date of Official map release
MAP_REVISED: Y/N; Y for yes if the map was revised, N for no if the map has not been revised
PREV_MAP_REL_DATES: Dates of prior map versions, if any
ZN_RELEASED: Date of official zone release
ZN_REVISED: Y/N, Y for yes if the zone polygon has been revised, N for no if the zone polygon has not been revised
PREV_ZN_REL_DATES: Dates of prior zone versions, if any
GEOPDFLINK: URL for the Official GeoPDF map of the fault zones in this 7.5 min. quad
REPORTLINK: URL for the Fault Evaluation Report (FER)
COMMENTS: Comments
FAULT_TRACE: Fault polylines and associated descriptions
Attribute Fields
FAULT_NAME: Name of the fault
FAULT_ZONE: Name of the fault zone
LINE_TYPE: Description of the fault type
Accurately Located
Approximately Located
Approximately Located, Queried
Inferred
Inferred, Queried
Concealed
Concealed, Queried
Aerial Photo Lineament (generally not used after 1981)
LINE_STYLE: Description of the line style used for symbolizing the fault trace
Solid Line (Accurately Located)
Long Dash (Approximately Located)
Long Dash with ? (Approximately Located, Queried)
Short Dash (Inferred)
Short Dash with ? (Inferred, Queried)
Dotted (Concealed)
Dotted with ? (Concealed, Queried)
Thin Dashed and Dotted (Aerial Photo Lineament; generally not used after 1981)
COMMENTS: Comments
QUAD_NAME: USGS 7.5 minute quadrangle official name
FAULT_LABEL: Queries, information, and names associated with fault traces
Attribute Fields
TEXT: Query locations, fault names, creep, year of historic rupture, etc.
ROTATION: Angle for query point and label text
QUAD_NAME: USGS 7.5 minute quadrangle official name
LEADER: Leaderlines associated with information for fault traces
Attribute Fields
QUAD_NAME: USGS 7.5 minute quadrangle official name
DISTRIBUTION INFORMATION
Distributor
Contact_Information
Contact_Organization: California Geological Survey, Seismic Hazards Program
Contact_Organization_Primary
Contact_Person_Primary
Contact_Person: Senior Engineering Geologist, Earthquake Fault Zoning Unit
Contact_Position: Project Manager
Contact_Address
Address_Type: mailing and physical address
Address: 801 K Street, MS 12-31
City: Sacramento
State: CA
Postal_Code: 95814-3532
Contact_Voice_Telephone: (916) 322-1019
Contact_Facsimile_Telephone: (916) 445-3334
Contact_Electronic_Mail_Address: SHMP@conservation.ca.gov
Hours_of_Service: Monday-Friday, 08:00-17:00, Pacific Time
Online_Source: http://maps.conservation.ca.gov/cgs/informationwarehouse/
Resource_Description: Official Web Service of Earthquake Fault Zones