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U.S. Geological Survey Open-File Report 02–296
Version 1.2
2002, revised 2010

Liquefaction Hazard and Shaking Amplification Maps of Alameda, Berkeley, Emeryville, Oakland, and Piedmont, California: A Digital Database

By

Thomas L. Holzer, Michael J. Bennett, Thomas E. Noce, Amy C. Padovani, and John C. Tinsley, III


INTRODUCTION

This Open-File Report is a digital database for hazard maps of liquefaction effects and shaking amplification in the Oakland, California, area. This accompanying pamphlet serves to introduce and describe the digital data. Paper maps are not included in the Open-File Report; instead PDF plot files are included that can be used to plot images of the hazard maps.

This digital database is based on a previously published map of surficial geology by Helley and Graymer (1997) as modified by R. Witter (digital communication, 2003) together with 210 newly acquired seismic cone penetration test (SCPT) soundings supplemented by unpublished commercial borings. The database identifies areas that have potential (1) to produce surface manifestations of liquefaction, for example, sand boils, ground cracks, and lateral spreading, and (2) to amplify ground shaking from earthquakes. The scale of the source map limits the spatial resolution (scale) of the database to 1:24,000 and smaller for the liquefaction map and 1:50,000 and smaller for the shaking amplification map; plotting at larger scales will not yield greater real detail. These maps depict the hazard at a regional scale and should not be used for site-specific design. Subsurface conditions can vary abruptly and borings are required to address the hazard at a given location. The liquefaction hazard map also does not account for local ground improvements that have been made to mitigate against the occurrence of liquefaction.

DATABASE CONTENTS AND PRESENTATION

The report consists of digital files representing the 8 parts of the database, some of which are presented in more than one format. The names of the files are unique designators based on the report identifier, of02-296, followed by part numbers and an extension indicating file type. Some of the files have been have been bundled and compressed with WinZip for convenience. The report file (of02-296_1.1.pdf) is provided as a Portable Document Format (.pdf) file and is also packaged with the database files in WinZip compressed form. The revision history file (version_history.pdf) is presented as a Portable Document Format (.pdf) file bundled in the database .zip files, as well as an individual download. The six .pdf map images may be downloaded individually or as a complete set in a single .zip file (of02-296_all_maps.zip). The liquefaction and shaking amplification databases are also packaged separately in compressed form with WinZip (.zip). The files and their identities are as follows:

1. Open-File Pamphlet: The text of the open-file pamphlet (this text, in Portable Document Format), which describes the database.

a. of02-296_1.1.pdf PDF file, 136 KB.

2. Liquefaction Map Images: The image files representing the liquefaction hazard map as a Portable Document Format file (.pdf). Files with an (-sg) extension contain the major streets and highways displayed on the map.

a. of02-296_2liq.pdf Portable Document Format, 472 KB

b. of02-296_2liq-sg.pdf Portable Document Format, 632 KB

3. Shaking Amplification Map Images: The image files representing the shaking amplification map as a Portable Document Format file (.pdf). Files with an (-sg) extension contain the major streets and highways displayed on the map.

a. of02-296_3sa.pdf Portable Document Format, 248 KB

b. of02-296_3sa-sg.pdf Portable Document Format, 416 KB

4. CPT Location Map Images: The image files representing the location of 210 SCPT soundings on the liquefaction map (scptliq) and the shaking amplification map (scptsa) Portable Document Format files (.pdf).

a. of02-296_4scptliq.pdf Portable Document Format, 488 KB

b. of02-296_4scptsa.pdf Portable Document Format, 264 KB

5. Liquefaction Map Database Package: The zipped file containing the open file pamphlet, revision list, and the data component files of the liquefaction hazard map, in ArcGIS format. The ArcGIS format files consist of shapefiles for the Hayward fault, the study area boundary, the liquefaction hazard, the latitude and longitude lines, the CPT locations, the streets and the major freeways. Additionally there are 3 .mxd files, named according to the unique identifier discussed above that were created using ArcMap 9.1, and the projection file.

a. of02-296_5liq.zip WinZip file, 1.3 MB

6. Shaking Amplification Map Database Package: The zipped files containing the open file pamphlet, revision list, and the data component files of the shaking amplification map, in ArcGIS format. The ArcGIS format files consist of shapefiles for the Hayward fault, the study area boundary, the latitude and longitude lines, the water boundary, the grid of shaking amplification values, the CPT locations, the streets and the major freeways. Additionally there are 3 .mxd files, named according to the unique identifier discussed above that were created using ArcMap 9.1, and the projection file.

a. of02-296_6sa.zip WinZip file, 3.9 MB

7. All map Images: The liquefaction map images, the shaking amplification map images, and the SCPT location map images (6 in total), in .pdf format, compressed into one .zip file.

a. of02-296_all_maps.zip WinZip file 2.4 MB

8. Added on January 21, 2010 are Google Earth KMZ files depicting the liquefaction hazard, the shaking amplification, and the CPT locations necessary for displaying the data in Google Earth.

The files are presented as a single zipped file. In order to dispay properly, unzip the folder and maintain the folder structure contained within the zipped file.

a. of02-296_GE.zip WinZip file, 759 kB

9. Revision List: A list of the parts of the report (including bundled packages of parts), indication of the current version number for the report and in which version each part was last revised, followed by a chronologic list describing any revisions (see REVISIONS, below).

a. version_history.txt ASCII text file, 4 kB

For questions about the content of this report, contact Tom Holzer.


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URL of this page: http://pubs.usgs.gov/of/2002/of02-296/
Maintained by: Michael Diggles
Created: August 9, 2002
Last modified: February 9, 2010 (mfd)