Relative Earthquake Hazard Map of the Portland Metro Region, Clackamas, Multnomah, and Washington Counties, Oregon (scale 1:62,500)

Identification_information:
Description:
Relative Earthquake Hazard Map of the Portland Metro Region, Clackamas, Multnomah, and Washington Counties, Oregon, originally published in hardcopy form by Oregon Department of Geology and Mineral Industries as IMS-1 (Interpretive Map Series number one) 

Abstract:
The accompanying digital files were used in production of a combined map of relative earthquake hazards covering the entire Portland, Oregon, metropolitan area.  The map, which encompasses an area of 24 cities and 1.3 million people, is the culmination of a four-year effort involving the Federal Emergency Management Agency, Metro and the Oregon Department of Geology and Mineral Industries.  The published map actually contains four maps.  Three small scale maps (1:216,000) delineate separate hazards for: amplification of ground shaking (Amp); liquefaction of water-saturated sand (Liq); and instability of slopes (Slp).  The relative earthquake hazards map (Rehm) is a composite hazard map depicting the relative hazard at any site due to a combination of the three separate hazards.  These four maps are available as separate files.  Digital map production was performed with ARC/INFO software.  For purposes of digital data release, the ARC/INFO files were translated to: MapInfo native format (.tab), MapInfo Interchange (mif/mid), ARC/INFO export (.e00) and ArcView (.shp) files. As with any digital format translation, users should be alert to the potential for problems and unpredictable results that may occur in translating from one program to another.

The associated digital map files are:
Amp (.tab, mif/mid, .e00, and .shp)
Liquef (.tab, .mif/mid, .e00, and .shp)
Relhaz (.tab, .mif/mid, .e00, and .shp)
Slope (.tab, .mif/mid, .e00, and .shp)

Purpose:
This map is a result of research supported by the U.S. Geological Survey (USGS), Department of the Interior, under USGS award numbers 14-08-001-G1985, 14-08-001-G2132, 1434-93-G-2324, and 14-08-0001-A0512 and the Federal Emergency Management Agency (FEMA) under award numbers EMS-95-K-0363 and EMS-96-CA-0055.  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.

Time_period:
The various elements of this mapping project were performed from 1993 through 1997.

Currentness:
The digital information is current to the date of map publication, which was 1997.  This digital information generally matches the published hardcopy map released as IMS-1 by the Oregon Department of Geology and Mineral Industries, Portland, Oregon.

Spatial_domain:
Bounding_coordinates:
West: -123.16 degrees
East: -122.32 degrees
North: 45.66 degrees
South: 45.27 degrees
Note: the extent of data coverage in each file is a one kilometer buffer beyond the Metro Region boundary line.

Keywords:
Theme:
Earthquake hazard; earthquake hazard_map; liquefaction; amplification of peak ground acceleration; slope instability

Place:
Portland Metropolitan Region_Oregon; Multnomah_County_Oregon; Clackamas_County_Oregon; Washington_County_Oregon

Point of contact:
Geology by Matthew A. Mabey, Department of Geology, Brigham Young University; Gerald L. Black and Ian P. Madin, Oregon Department of Geology and Mineral Industries; Dan B. Meier, Woodward-Clyde Consultants, Portland, Oregon; T. Leslie Youd and Celinda F. Jones, Department of Civil and Environmental Engineering, Brigham Young University; J. Benjamin Rice, GIS Layout, Metro Regional Services, Portland, Oregon


Dataset credit:
J. Benjamin Rice, GIS Layout, Metro Regional Services, Portland, Oregon, phone 503/797-1597

Grid coordinate system and parameters:
Digital_files_in:
Oregon_State_Plane_Coordinate_System
North_Zone
Unit:
International_feet
Datum:
North_American_Datum_1983
Ellipsoid:
GRS_80