Details
Map Projection Name: Transverse Mercator
Scale Factor at Central Meridian: 0.999600
Longitude of Central Meridian: -114.000000
Latitude of Projection Origin: 42.000000
False Easting: 500000.000000
False Northing: 100000.000000
Planar Coordinate Information
Planar Distance Units: meters
Coordinate Encoding Method: coordinate pair
Coordinate Representation
Abscissa Resolution: 0.000100
Ordinate Resolution: 0.000100
Geodetic Model
Horizontal Datum Name: North American Datum of 1927
Ellipsoid Name: Clarke 1866
Semi-major Axis: 6378206.400000
Denominator of Flattening Ratio: 294.978698
Process step 1
Process description: Methods for classifying site classes are given in Building Seismic Safety Council (1997, pp. 32-35). In general, site classes are determined with geotechnical properties of earth materials within 100 feet (30 m) of the ground surface. These include average shear wave velocity and average standard penetration resistance. However, these data are not available for many parts of the study area and making field measurements was beyond the scope of this project. Geotechnical properties were estimated for geologic units using procedures similar to those employed in other states (Wills and others, 2000; Palmer and others, 2004):
Measurements of shear wave velocity and standard penetration resistance were compiled for geologic units within the map area and surrounding portions of the eastern Snake River Plain. The geologic units were taken from 1:24,000-scale mapping (Phillips and Welhan, in preparation). Classification was based upon this compilation. No regional data were found for some units. Classification of these units was based upon published measurements of similar units in the western United States.
Areas of bedrock overlain by >10 feet of loess were identified with water well records (IDWR, 2010) and classified on the basis of loess.
County soil maps (Jorgensen, 1979; Noe, 1981; Miles, 1981; Salzmann and Harwood, 1973) were examined for areas underlain by thick soft clay, as identified with plasticity indexes > 20, water content of >40%, and total thicknesses of >4 feet. No such soils have been mapped in the study area. Assignment of class F requires a detailed geotechnical evaluation and class A is used only in the Eastern United States. Therefore, these classes are not used on the map.
SPREADSHEETS AND ARCGIS PERSONAL GEODATABASE
NEHRP site classes for each geologic unit in study area are given in the spreadsheet listed at the end of this file. The average shear wave velocities and standard penetration resistances used in preparing these maps are also given. NEHRP site class definitions are given in another spreadsheet. An ArcGIS personal geodatabase is also provided.
Process date: 2010
at time 11081000
Source 1
Contribution: REFERENCES CITED
Building Seismic Safety Council, 1997, NEHRP recommended provisions for seismic regulations for new buildings and other structures: Part 1, Provisions (FEMA 302): Building Seismic Safety Council, 334 p.
IDWR, 2010, Water well logs: Idaho Department of Water Resources, Boise. [Available at http://www.idwr.idaho.gov/GeographicInfo/GISdata/wells.htm.]
ITD, 2010, Test hole lithology and geotechnical data from bridge drawings: Idaho Transportation Department, Boise.
Jorgensen, W., 1979, Soil survey of Jefferson County, Idaho: U.S. Department of Agriculture, Soil Conservation Service, 219 p. 66 map plates, scale, 1:20,000.
Noe, H.R., 1981, Soil survey of Madison County area, Idaho: U.S. Department of Agriculture, Soil Conservation Service, 128 p., 29 map plates, scale 1:24,000. [Available at http://soildatamart.nrcs.usda.gov/]
Miles, R.L., 1981, Soil survey of Bonneville County area, Idaho: U.S. Department of Agriculture, Soil Conversation Service, 108 p., 58 plates, scale 1:24,000.
Palmer, S.P. and others, 2004, Liquefaction susceptibility and site class maps of Washington State by county: Washington Department of Natural Resources, Division of Geology and Earth Resources Open File Report 2004-20.
Payne, S.J., 2006, Data and calculations for development of rock and soil design basis earthquake (DBE) parameters at the Materials and Fuels Complex (MFC): Idaho National Laboratory, Idaho Falls, INL/EXT-05-00926 Rev. 1, 356 p.
Phillips, W.M., 2010, unpublished data: Idaho Geological Survey, Moscow.
Phillips, W.M. and J.A. Welhan, in preparation, Geologic map of the Lewisville quadrangle, Bonneville and Jefferson Counties, Idaho: Idaho Geological Survey Digital Web Map, scale 1:24,000.
Sykora, D.W., J.P. Koester, and M.E. Hynes, 1991, Seismic stability evaluation of Ririe Dam and reservoir project, Report 2 - Stability calculations, analysis, and evaluation, Appendix D, Dynamic response analysis of Ririe Dam: Geotechnical Laboratory, Department of the Army, Waterways Experiment Station, Corps of Engineers, Technical Report GL-91-22, Figures 14 and 15. [available at http://handle.dtic.mil/100.2/ADA268785].
Wills, C.J., M. Petersen, W.A. Bryant, M. Reichle, G.J. Saucedo, S. Tan, G. Taylor, and J. Treiman, 2000, A site-conditions map for California based on geology and shear-wave velocity: Bulletin of the Seismological Society of America, v. 90, no. 6B, pp. S187-S208.
1. Process
Date and time:
20100621
at time 143338
Tool location:
C:\Program Files\ArcGIS\ArcToolbox\Toolboxes\Data Management Tools.tbx\DefineProjection
Command issued
DefineProjection SiteClass_IDfalls PROJCS['NAD_1927_StatePlane_Idaho_East_FIPS_1101',GEOGCS['GCS_North_American_1927',DATUM['D_North_American_1927',SPHEROID['Clarke_1866',6378206.4,294.9786982]],PRIMEM['Greenwich',0.0],UNIT['Degree',0.0174532925199433]],PROJECTION['Transverse_Mercator'],PARAMETER['False_Easting',500000.0],PARAMETER['False_Northing',0.0],PARAMETER['Central_Meridian',-112.1666666666667],PARAMETER['Scale_Factor',0.9999473684210526],PARAMETER['Latitude_Of_Origin',41.66666666666666],UNIT['Foot_US',0.3048006096012192]] SiteClass_IDfalls