California Department of Conservation (DOC), California Geological Survey (CGS) Seismic Hazard Zoning Program

Metadata for Seismic Hazard Zones (SHZ)
Seismic Hazard Zone Map of the Clifton Court Forebay Quadrangle

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: 2021
Publication_Time: Unknown
Title: GIS files of Official Maps of Seismic Hazard Zones
Series_Information:
Official Maps of Seismic Hazard Zones
Publication_Information:
Publication_Place: Sacramento, CA
Publisher: Department of Conservation, California Geological Survey

Suggested_Citation:
California Geological Survey. 2021, Official Maps of Seismic Hazard Zones: GIS files of Official Maps of Seismic Hazard Zones - Clifton Court Forebay, Sacramento, CA. Department of Conservation, California Geological Survey. http://maps.conservation.ca.gov/cgs/informationwarehouse/. Accessed [Day] [Month] [Year]

Description
Abstract: This is a digital Seismic Hazard Zone Map presenting areas where liquefaction and landslides may occur during a strong earthquake. Three types of geological hazards, referred to as seismic hazard zones, may be featured on the map: 1) liquefaction, 2) earthquake-induced landslides, and 3) overlapping liquefaction and earthquake-induced landslides. In addition, a fourth feature may be included representing areas not evaluated for liquefaction or earthquake-induced landslides. Developers of properties falling within any of the three zones may be required to investigate the potential hazard and mitigate its threat during the local permitting process.

Purpose: The map is used by cities and counties to regulate development and by property owners selling property within areas where seismic hazard zones have been identified. Local governments can withhold development permits until geologic or soils 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 a seismic hazard zone as required by the Seismic Hazards Mapping Act of 1990 (Public Resources Code, Division 2, Chapter 7.8).

For information regarding the scope and recommended methods to be used in conducting the required site investigations, see California Geological Survey Special Publication 117A, Guidelines for Evaluating and Mitigating Seismic Hazards in California.

Supplemental_Information: This map may not show all areas that have potential for liquefaction or landsliding. Also, a single earthquake capable of causing liquefaction or triggering landslide failure will not uniformly affect the entire area zoned. The identification and location of liquefaction and earthquake-induced landslide zones are based on the best available data. However, the quality of data used is varied. Zone boundaries have been drawn as accurately as possible at the map scale (1:24,000).

These data do not include Alquist-Priolo Earthquake Fault Zones, if any, that may exist in this area. Please refer to the latest Official Maps of Earthquake Fault Zones for disclosures and other actions that are required by the Alquist-Priolo Earthquake Fault Zoning Act. For more information on this subject see California Geological Survey Special Publication 42.

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. 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: 2021-08-17
Currentness_Reference: 2021
Status Progress: Complete
Maintenance_and_Update_Frequency: Unknown

Spatial_Domain
Bounding_Coordinates
West_Bounding_Coordinate: -121.625002091
East_Bounding_Coordinate: -121.500001083
North_Bounding_Coordinate: 37.874998999
South_Bounding_Coordinate: 37.7499979902

Keywords
Theme
Theme_Keyword_Thesaurus: None
Theme_Keyword: Seismic Hazard Zone Map
Theme_Keyword: earthquake hazards
Theme_Keyword: earthquake hazard identification and mitigation
Theme_Keyword: landslides
Theme_Keyword: liquefaction

Place
Place_Keyword_Thesaurus: None
Place_Keyword: City:
Place_Keyword: County: Alameda County, Contra Costa County, San Joaquin County
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) 2021 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 Map of Seismic Hazard Zones, Clifton Court Forebay Quadrangle (2021)", and (3) For publication in a report in modified form; cite on figure or in text as "Modified from California Geological Survey, Official Map of Seismic Hazard Zones, Clifton Court Forebay Quadrangle (2021)".

Point_of_Contact
Contact_Information
Contact_Organization: California Geological Survey, Seismic Hazards Program
Contact_Person_Primary
Contact_Person: Senior Engineering Geologist, Seismic Hazard 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: As of 2016, the format of the digital GIS files has been changed and there are now three feature classes, each with associated attributes. In addition, for some quadrangles there may be a feature representing areas that were not evaluated for seismic hazards. For the most part, attribute values were automatically generated and populated manually. Attribute values were summarized and reviewed via queries against the features and any inconsistencies or errors were corrected.

Quantitative_Attribute_Accuracy_Assessment:

Attribute_Accuracy_Explanation: Areas where previous occurrence of liquefaction or landslide movement, or local topographic, geological, geotechnical and subsurface water conditions indicate a potential for permanent ground displacements such that mitigation as defined in Public Resources Code Section 2693(c) would be required.

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.