PERMFILE64516

• Permit No: M2001035
• IBM Index Class Name: Permit File
• Doc Date: 7/8/2001
• Doc Name: PROBABILISTIC SEISMIC HAZARD ANALYSIS TROUT CREEK DAM PROJECT NEAR BUENA VISTA CHAFFEE CNTY COLO
• Media Type: D
• Archive: No

XII coNTENTs
Responsd The motion in a system resulting from an excitation
under specified conditions
Response spectrum The peak respon5! of a series of simple her-
monie osdllators of different natural period when subjected meth-
ematieally to s particular earthquake ground motion. The re-
sponse spectrum cosy be plotted as a curve on• tripartite
logarithmic graph paper showing the variation of the peak spectral
a«eleration, diaplaament, and rel«ity of the oscillator es a
function of vibration period and damping.
Return period. The average period of time or recurrence interval
between events causing ground shaking ezaeding a particular
level at a ate; the reciprocal of annual probability of exceedance. A
return period of 475 years means that, on the average, a particular
level of ground motion will be ezceeded once in 475 yeah.
Risk. See Earthquake risk.
Rock. See Bedrock.
Rupture velocity. The vet«ity at which the fault rupture propa-
gate along ifs length. The rupture vet«ity is usually some frac-
tion of the sheer wave vel«ity and in the range 1.5 to 4.5 km/s for
most earihquekea it alecU the elective stress.
9-wave (56ear wave). Body wave in which the particle motion is at
right angles to the dvection of wave propagation. SH and SV
denotes planes of polarization of wave. Swas•e velocity may be
measured by in-hole geophysical procedures to determine the
dynamic shear moduli of the materials through which the wave
passes.
Safe shuWown earthquake (SSE). A design earthquake used by
the U.S. Nuclear Regulatory Commission in nuclear powerplent
ailing: the largest possible earthquake at the site, considering the
regional and local geology and seismology end specified charac-
teristics of loealand aubsutfacematerial. Important nuclear power
plant strvdures, systems, and componenU are designed to remain
intact during the SSE. See Operating basis earthquake.
Saturated soil. Soil with zero air voids. A soil which has its in-
terstices or void apace filled with water to the point where carol
«N rs.
Seismic source zones. Areas of spatially homogeneous earthquake
activity,
3eismle save. M elastic wave generated by an earthquake or ex-
plosion which cause only a temporary displacement of the
medium, the recovery of which is accompanied by ground
vibration.
Seismogram. A record of ground motion or of the vibration oC a
atrutture caused Dy a disturbance, such as an underground nuclear
detonation or an earthquake. See Accelerogram
Seismograph. A system Cor amplifying and recording the signals
from seismometers.
Seismometer. The intrument used to tranform seismic wave
enegry into an electrical voltage. Most seismometers are vet«ity
detector their outputs being proportional to the vet«ity of the
inertial mass with respect to the seismometer s case (which is pro-
portional to the vet«ity of the earth motion.) Below the natural
frequency, the response of most geophones decreases linearly with
frequency so that they operate a, accelerometers.
9eismoteetonic province. A geographic Brea characterized by
similarity o[ geologic structure and earthquake characteristics.
9emitivity. The smallest change in a quantity that a detector can
detect.
Shear modulus (Rigidity). The ratio between shear stress and
sheer strain in simple shear.
Shear wave. Equals $wave equals tranverse wave: A body wave
in which the particle motion is perpendicular to the direction of
propagation.
Shear wave velocity. See Modulru.
Simr shear. The state of stress at the point where only shearing
st ~s act on any two perpendicular planes.
Site vicinity. The geographical region within about 70.km radius of
the center of the site.
SneB's law. When a wave crosses a boundary, the wave changes
direction such that the sine of the angle of incidence divided by the
vet«ity io the first medium equals the sine of the angle of refnc•
lion divided by the vet«ity in the second medium
SoR soi4 A general dexription for soil which has a shear wave
vel«ity less than fi00 cols. See 6~rm Boil, Bedtoet
Sonic log. A record of the seismic vet«ity (or of interval time) as a
function of depth
Speeillc dissipation. See Q.
Standard deviation. The standard deviation, o, of n measure-
ments of a quantity r,, with respect to the mean, .e, ie:
N l SS
N-1 ~-r
Standing wave. A wave produced by simultaneous transmission in
opposite directions of two similar wavesa it may result in fixed
points of zero amplitudes tolled nodes.
Station. A ground position at which a geophysical instrument or
seismograph is set up for an observation.
Steady-state vibration. Vibration in a system where the vet«ity
of each particle is a continuing periodic quantity.
Stocheatic. Random; value determined entirely by thence.
Strain The change in length per unit of length in a given direction
which a'bady subjected to deformation undergoes.
Strain dependent property. A property exhibited by soil wherein
the magnitude of a physical property depends on the magnitude of
the induced strain.
Straligraphy. The order of succession of the different sedimentary
r«k formation in a region.
Strength of earthquake. ]n current usage, it is often expressed in
terms of the peak ground acceleration recorded or predicted for a
particular earthquake, expressed usually in g unite, where I g is
an acceleration equal to that of gravity, or 980 cm ~.
Stress drop. Ace=oe-v, where as is the initial stress before the
earthquake and o, is the stress alter the earthquake. For the 1971
Sera Fernando, Calif. earthquake, the average initial strew is es-
timated to have been about 100 baro end the stress drop to have
been about 60 ban. Stress drop controls the high-frequency
spectral content oC earthquake ground motion.
Stress (electivel. In modeling en earthquake, the elective stress is
defined as o=o,-o, where o, is the stress before the earthquake
and or is the frictional stress acting to resist the fault slip.
Strike•slip fault A fault in which movement is principally horizon-
tal. The San Andreas fault is strike-slip.
Strong motion. Cround motion of sulicient amplitude to be of en-
gineeringinterest in the evaluation of damage due to earthquakes
or nuclear explosions.
Structural features. Features such es faults and folds which are
produced in rock by movements after deposition, and commonly
after consolidation, of the constituent sediment.
Surface waves. Seismic energy which travels along or near the
surface. Rayleigh and Lava waves.
Surface wave magnitude. Ms. See Magnitude.
TecWnic province. As defined by the U.S. Nuclear Regulatory
Commission, it is a region of the North American continent
characterized by the uniformity of the geologic struRures con-
tained therein.
Tectonic structure. As defined by the U.S. Nuclear Regulatory
Commission, it is a large list«ation or duWrtion within the
earth's crust whose extent is greater then several kilometers.
Tectonics. A branch of geology dealing with the broad architecture
of the upper part of the earth's crust in terms of the origin and