Online link | https://geo-nsdi.er.usgs.gov/metadata/map-i/2679/PGA250.faq.html |
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Description | Probabilistic seismic hazard maps were prepared for Alaska portraying peak horizontal ground acceleration and horizontal spectral response acceleration for 0.2, 0.3, and 1.0 second periods with probabilities of exceedance of 10% in 50 years and 2% in 50 y |
Originators | Wesson, Robert L.; Frankel, Arthur D.; Mueller, Charles S.; Harmsen, Stephen C.; and Rukstales, Kenneth S. |
User defined items in data tables for polygon coverages for bedrock geology, quaternary surficial units and residuual deposits (see readme.txt for description of coverages): >MapUnit = 1 to 4 character abbreviation of geologic unit >name = unit is surficial or bedrock >SurfType = type of surficial unit >LithPri = primary lithology of unit >LithSec = secondary lithology of unit >LithTer = tertiary lithology of unit >Form = formal Formation name >Member = formal Member within a Formation >Group = formal Group name >Super Group = formal Supergroup name >RockClass = major rock-type classification >Age = era, age, epoch, etc. >Geochr = geochron >GeochrTech = technique for detemining geochron >GeochrRef = geochron reference >Fossil = yes/no fossils collected >FossilType = type of fossil, phylum etc. >FossilRef = fossil reference, e.g. a report >CorrelExtr = correlation of unit is extrapolated or >interpolated from other data >Origin = author interpretation of environment of origin of >unit = potential mineral resource >Color =weathered color of rock as exposed in the map area >MinPri = primary mineral in unit >MinSec = secondary mineral in unit >MinOth = other minerals found in unit >ClastPri = primary clast(s) in unit >ClastSec = secondary clast(s) in unit >Cement = compositon of cement or matrix >ThickApprx = approximate thickness of unit >ThickRange = range of thickness of unit >BedThin = there are thin beds within unit >BedMedium = there are medium beds within unit >BedThick = there are thick beds within unit >ContUp = nature of upper contact >ContLow = nature of lower contact >FolPri = primary foliation >FolSec = secondary foliation >FolTer = tertiary foliation >CMPM = contact metamorphic minerals >RMPM = prograde regional metamorphic minerals >RMRM = retrograde regional metamorphic minerals >DeformAge = interpreted geoogic age and/or orogeny of >deformation = isotopic technique used to date deformation >DeformRef = reference to absolute or relative age of deformation >Comments = additional information about unit User defined items in data tables for line coverages of contacts >contact nature of geologic unit contact, may be frame, approximate, exposed, or concealed. Frame is arc along the quadrangle boundary. User defined items in data tables for line coverages of faults f_type = confidence-level of fault location: approx, inferred, mapped, projected fault_type = type of fault: dipslip, strikeslip, unkown movement = sense of movement on fault User defined items in data tables point coverges of structural data dip = angular measure of dip of planer feature azimuth = 360 degree compass direction of planar or linear feature = 360 degree direction of linear symbol type = type of feature: bd = bedding, bdh = bedding horizontal, if = inclined igneous foliation, vf = vertical igneous foliation, nic = nonthroughgoing inclined close-spaced joints, nim = nonthroughgoing inclined medium-spaced joints, niw = nonthroughgoing inclined medium-spaced joint; nvc = nonthroughgoing vertical close-spaced joints, nvm = nonthroughgoing vertical medium-spaced joints, nvw = nonthroughgoing vertical widely-spaced joints, tim = throughgoing inclined medium-spaced joints, tiw = throughgoing inclined widely spaced joints, tvc = throughgoing vetical close-spaced joints, tvm = throughgoing vertical medium-spaced joints, tvw = throughgoing vertical wide-spaced joints, jmv = joint with movement, mnf = minor fault. symbol_ang = symbol angle calculated for proper plotting in Arc/Info dip direction, will be 90 or 270 degrees off of azimuth = sense of rotation, depending on direction of dip
File readme.txt included with the data set.