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USGS Faults

faultsThis dataset contains quaternary faults within 50 miles of Los Angeles County.

Click here to download the shapefile


The source of this data is the USGS Earthquake Hazards Program. The data was downloaded from the Faults and Folds Database website (click to access).

The USGS has comprehensive metadata on this dataset: click to view, but in case the location changes I have made a .pdf of the file for download (click to download the .pdf)


In order to make this dataset a bit more useful for County purposes, I have clipped the dataset to include only faults within 50 miles of LA County, and assigned the County boundary to the faults so that you can show only faults within the County using the “County” field.


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Data Field Descriptions

Check the attached metadata for all of the coding, but the two most important fields are CODE and NAME

CODE: value for symbolizing faults

>First digit: fault location code
>1 = well located
>2 = moderately well located
>3 = inferred
>Second digit: faultage
>1 = historic
>2 = Holocene < 15,000 years
>3 = late Quaternary < 130,000 years
>4 = mid to late Quaternary < 750,000 years
>5 = Quaternary < 1,600,000 years
>6 = class B
>7 = unknown
>0 = unknown
>Third digit: fault slip rate code
>1 = >5 mm/year
>2 = 15
>3 = .2 1
>4 = < .2 mm/year

NAME: fault name

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

Contact Information
Greg Smoczyk

US Geological Survey
Geologic Hazards Team


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