This dataset represents 1:24,000-scale fault and descriptive data and shows the location and type of faults in the Linnton 7.5-minute quadrangle, Multnomah and Washington Counties, Oregon. This file is one in a set of four files which are provided to the user in two formats: MapInfo .tab and ESRI .shp format files. The other three files in the set include: Linnton_Bedrock, Linnton_Folds, and Linnton_Surficial. The quadrangle is located in the northwestern portion of the Portland urban area in NW Oregon. For the Linnton quadrangle, we have chosen to present two maps: a bedrock map that shows only the bedrock geology inferred to extend beneath the surficial deposits, and a companion map that shows only the surficial deposits.
Overlay map to go with the bedrock geology map. The purpose of the project is to improve geologic mapping in the Portland urban area in order to better understand earthquake hazards.
The CD contains digital files with various map coverages created in MapInfo Professional version 9.1 (.tab) and a screen graphic of the map in Adobe PDF format. Digital map coverages are also provided as ArcView version 3.3 Shapefile (.shp) format for ESRI users. Accompanying the screen graphic of the map, is a text file (pdf format) describing the map units along with a discussion of the quadrangle's structural history. This digital data is not field-checked and comes with no guarantees as to its accuracy.
Field work conducted in 2006 and 2007, data compilation-2008
Many more faults could exist in the quadrangle than are displayed on the map (O-08-06map.pdf). The faults displayed on the map where traced using available exposure and evidence from nearby outcrops and subsurface data (water well logs, etc). However, the authors believe that the relative lack of exposure at the surface makes the delineation of these faults "approximate" without more extensive fieldwork and subsurface data. This dataset was tailored fo use at a scale of 1:24,000. Use at larger scale would be inappropriate. There is uncertainty in the position of the faults from the field mapping process, the original map preparation, and the digitizing process. Therefore, DOGAMI makes no warranty as to the currency, completeness, accuracy or utility of any specific data. This disclaimer applies both to individual use of the data and aggregate use with other data. It is strongly recommended that careful attention be paid to the contents of the metadata file associated with these data. DOGAMI makes no warranty as to the currency, completeness, accuracy or utility of any specific data. This disclaimer applies both to individual use of the data and aggregate use with other data. It is strongly recommended that careful attention be paid to the contents of the metadata file associated with these data. User should use caution when overlaying other data sets and should not make legally binding decisions from this data. Any person using the information presented here should fully understand the data collection and compilation process before beginning their analysis/use. The burden of determining fitness for use lies with the user. To avoid the risk of misinterpretation, invalid results, and erroneous conclusions, the users must consider original map scale, collection methodology, and any other conditions specific to every data element and each dataset as a whole. Potential users are advised to consult with DOGMAI to gain an understanding of the inherent limitations of this data set and its scope of inference. Also, the user must be aware that errors and conditions originating from physical sources involved in developing a dataset may be reflected in the data, and that the digital processing performed during preparation, storage, and transmission of the dataset may have exacerbated such errors and/or introduced additional ones.
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This research was supported by the U.S. Geological Survey (USGS), Department of the Interior, under USGS award number 03HQAG0013. The views and conclusions contained in this document are those of the authors and should not be interpreted as necessarily representing the official policies, either expressed or implied, of the U.S. Government. The Oregon Department of Geology and Mineral Industries created and maintains the spatial data sets. Credit should always be given to the data source and/or originator when the data is transferred or printed.
Prior to release of map-on-demand files and metadata, the author was given final digital data sets and paper plots for checking against the source map(s) to verify the linework and attributes. Also, the author was asked to check the metadata and accompanying files for completeness and accuracy.
All lines have one unique label.
Spatial data is presented in the form of lines characterizing faulting in the Linnton quadrangle. All fault lines are fully attributed. This feature class must be used in conjunction with the other feature classes in this dataset for a full representation of the Linnton bedrock map (O-08-XXmap.pdf).
Appropriate to final map scale of 1:24,000.
unknown
Linework was captured by heads-up digitizing on the computer screen using a bedrock polygons as an overlay on a DRG of the quadrangle. The digital linework was edited and attributed using MapInfo Pro 9.1.
Internal feature number.
ESRI
Feature geometry.
ESRI
Fault name: unknown, Germantown Road Fault, Oatfield Fault, Portland Hills Fault, Portland Harbor Fault, and East Bank Fault
Oregon Department of Geology and Mineral Industries
Fault type or displacement: normal and nd (no data)
Oregon Department of Geology and Mineral Industries
Fault Certainity: inferred and concealed
Oregon Department of Geology and Mineral Industries
Fault Plane Direction (bearing): ne, northeast; nw, northwest; w, west
Oregon Department of Geology and Mineral Industries
Fault Plane Degree (dip): nd, no data
Oregon Department of Geology and Mineral Industries
The upthrown side of faults are labeled on the source map (O-08-06map.pdf) with "ball and bar". The faults are represented by arcs (line direction) that are oriented with the upthrown sides to the right of the arcs according to the direction the arcs are pointing. The downthrown sides are to the left of the arcs (line direction) according to the direction the arcs are pointing. Each line has associated attributes of FLT_NAME (name of fault, formal and informal) and FLT_TYPE, types of faults. Each line also has associated attribute of FLT_CERT (certainity), FLTPL_DIR (fault plane directions or strike), and FLTPL_DEG (dip).
For complete decription of attributes, see O-08-XXprint.pdf and on the source map, O-08-XXmap.pdf.
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Contact Nature of the Northwest Information Center by e-mail, phone, or letter explaining what products are needed. All DOGAMI publications, both in and out of print, are available for inspection at the Department's offices (most reports "on file" are in the Portland office only) and at many state-document depository libraries in Oregon, including most Oregon college and university libraries. Publications are also available via interlibrary loan from the Oregon State Library, State Library Building, Salem, OR 97310.
No warranty, expressed or implied is made regarding the accuracy or utility of the data described and/or contained herein, nor shall the act of distribution constitute any such warranty. This disclaimer applies both to individual use of the data and aggregate use with other data. It is strongly recommended that careful attention be paid to the contents of the metadata file associated with these data. The Oregon Department of Geology and Mineral Industries shall not be held liable for improper or incorrect use of these data. This information may be updated without notification.
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