An Update of Quaternary Faults of Central and Eastern Oregon

By R.J. Weldon, II¹, D.K. Fletcher¹, E.M. Weldon¹, K.M. Scharer¹, and P.A. McCrory¹

U.S. Geological Survey
Open-File Report 02-301
Version 1.0

2003

U.S. Department of the Interior
Gale A. Norton

U.S. Geological Survey
Charles G. Groat, Director

This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey (USGS) editorial standards or with the North American Stratigraphic Code. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

¹ Department of Geological Sciences, University of Oregon, Eugene, OR 97403
² U.S. Geological Survey, M.S. 977, 345 Middlefield Road, Menlo Park, 94025

Abstract

This is the online version of a CD-ROM publication. We have updated the eastern portion of our previous active fault map of Oregon (Pezzopane, Nakata, and Weldon, 1992) as a contribution to the larger USGS effort to produce digital maps of active faults in the Pacific Northwest region. The 1992 fault map has seen wide distribution and has been reproduced in essentially all subsequent compilations of active faults of Oregon. The new map provides a substantial update of known active or suspected active faults east of the Cascades. Improvements in the new map include (1) many newly recognized active faults, (2) a linked ArcInfo map and reference database, (3) more precise locations for previously recognized faults on shaded relief quadrangles generated from USGS 30-m digital elevations models (DEM), (4) more uniform coverage resulting in more consistent grouping of the ages of active faults, and (5) a new category of "possibly" active faults that share characteristics with known active faults, but have not been studied adequately to assess their activity. The distribution of active faults has not changed substantially from the original Pezzopane, Nakata and Weldon map. Most faults occur in the south-central Basin and Range tectonic province that is located in the backarc portion of the Cascadia subduction margin. These faults occur in zones consisting of numerous short faults with similar rates, ages, and styles of movement. Many active faults strongly correlate with the most active volcanic centers of Oregon, including Newberry Craters and Crater Lake.

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Files

1_README.TXT Overview of the orqfault project

attributes.txt Fault attributes in Microsoft tab-separated-ASCII format

attributes.xls Fault attributes in Microsoft Excel format

files.txt List of files for the CD-ROM version of this publication

notes-references.txt Fault notes and references in tab-separated-ASCII format

notes-references.xls Fault notes and references in Microsoft Excel format

orqfaults.apr ArcView project file. The ArcView project orqfaults.apr can be run on a computer that has ArcView installed. The project can be copied to a hard drive but since the project relies on the files in the faults and hillshade directories, they must also be copied and must remain in the same relative location to the ArcView project

orqfaults.txt Note about copying ArcView project files onto your hard disc (basically the note above)

Suggested citation and version history

Folders

faults/e00_files
orqfaults_dd.e00 - Arc/Info interchange format for faults in geographic coordinates
orqfaults_lam.e00 - Arc/Info interchange format for faults in lambert projection

faults/info .dir, .dat, and .nit files for Arc/Info coverages

faults/orqfaults_dd Arc/Info coverage of faults geographic coordinate system

faults/orqfaults_lam Arc/Info coverage of faults in lambert projection

hillshade -- Hillshade images; One degree hillshade images, yy = latitude and xxx = longitude. Provided as .tif, .aux, and .tfw files.

pdf/1to500000.pdf Hillshade image with faults.

pdf/1to500000ventgeol2.pdf Hillshade image with faults, vents, and Quaternary geology

pdf
yyxxx.pdf: One-degree hillshade images with faults, yy = latitude and xxx = longitude

For questions about the content of this report, contact Pat McCrory

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