Seismic-Hazard Maps for Alaska and the Aleutian Islands: PGA250

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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.

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Overview of attributes

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
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
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.