496 Index
seismic phases, S waves (continued):
ScS 670 S, 176
S diff , 58, 86, 108–9, 176, 182–3
S diff200 S diff , 176
S diff400 S diff , 176
S diff670 S diff , 176
SdS, 172–3
S g , 122
SKS, 58, 86, 109, 163–5, 168, 174, 181–2
SKKS, 58, 86, 163–5, 168
SKKKS, 168
S n , 122
SPdKS, 174
sPS, 165–6
sS, 3, 108, 163–4, 176
sScS, 3, 108, 176
sScS2, 3
sScS3, 3
sScS4, 3
sS diff , 58
SS, 3, 58, 86, 108, 163–7, 176, 383–4, 395, 433
sSKS, 164
SSS, 3, 86, 108, 164–6, 176
sSS, 108
S4, 3, 86, 164, 166, 176
S 220 S, 176
S 400 S, 176
S 410 S, 395
S 520 S, 395
S 660 S, 395
S 670 S, 176
S5, 166, 176
seismic ray, 6, 65
seismic section, 143–4
seismic slip
continental deformation zones, 340–1
subduction zones, 323–4
seismic sources, 1, 4, 141
air gun, 148–9
double couples, 220, 240, 242
equivalent body force, 220, 240
exploding reflectors, 152
explosive, 245
force couples, 241–2
isotropic, 245, 247
magnitudes and moment, 4, 263–6
moment tensors, 239–51
moving point, 231
point, 56, 152–3
scaling relations, 268–9
single forces, 240–1
spectra, 266–8
stress drop, 269–73
time function, 222, 230, 235, 258–9
Vibroseis unit, 149–52
seismic spectrum, 59
seismic strain rate tensor, 341
seismic velocity see velocity
seismic waves
attenuation, 114, 185–98
introduction to, 1–3
in layered medium, 62–86
phases, 2–3
plane waves, 54–5, 61
ray paths, 2, 65, 120–1
seismic wave equation, 53–4
signal filtering, 369
in spherical earth, 157–62
spherical waves, 55–6
string waves, 29–38
travel times, 60–1, 119–20
see also body waves; surface waves
seismicity
deep, 289–90, 312, 319–22
geographic distribution, 9–10, 289
temporal distribution, 11, 274–6
seismograms
common midpoint (CMP) stacking, 141–4
cross-correlation, 383–5
data processing sequence, 156–7
data sampling, 385–7
digital, 405–7
Fourier analysis, 369–77
introduction to, 1–3
linear systems, 377–85
mode observation, 110
multichannel, 140–1
P and S waves, 57–8, 60–1
receivers, 141
record sections, 122
rotated, 57–8
stacking, 391–7
synthetic, 111, 383
seismological networks
arrays, 407, 408–9
global, 407–8
regional, 407, 410–12
seismometers, 1
analog, 401
arrays, 408–9
broadband, 404
damped harmonic oscillator, 190–1, 398–9
digital, 403–7
earth noise reduction, 400
electromagnetic, 401–2
force-feedback, 403
IDA gravimeter, 403
networks, 407–12
ocean bottom, 408
response, 229–30, 379, 401–2
strainmeter, 404, 406
Streckheisen, 404
strong-motion, 404
time recording, 405
types of, 141, 385, 398, 400–5
WWSSN, 402–3
Wood–Anderson, 263
seismometry
definition, 398
development of, 401
seismoscopes, 400–1
self-similarity, 274
shadow zone, 161, 167–8
Shah function, 385
shape-preferred orientation (SPO) anisotropy, 177
shear modulus, 50
shear stresses, 40, 43–5, 350–1
shear wave splitting, 181–2
shear waves see S waves
shift theorems, 374
shock wave, from explosion, 245
Sierra Nevada, crustal structure, 129–30
signal enhancement, reflection seismology, 145–7
signal processing, 369
signals, finite length, 380–3
silent earthquakes, 262
sinc function, 73, 381, 383
single forces, 240–1
single-couple source, 241
singlets, normal mode, 104, 114
660-km discontinuity, 163–4, 171, 202–3, 205–7,
315–20
slab pull, 314, 315, 324, 330
slabs, subducting, 286, 308–21
slant stacks, 147, 396
Slichter mode, 106
slider model, 360
sliding, stick-slip, 359–64
sliding friction, 352
slip
aseismic, 262, 324, 340
at faults, 218, 254–6, 262–3
seismic, 323–4
slip partitioning, 322
slip vector, 218, 228, 243, 293
slow earthquakes, 271
slowness
horizontal, 69
intercept-slowness, 137–40
and ray parameter, 69–70
vector, 69
vertical, 69
SLR see Satellite Laser Ranging
slump earthquakes, 241, 346–7
Snell’s law
and Fermat’s principle, 71
and Huygens’ principle, 72–3
P–SV waves, 66–7
SH waves, 68–9
in spherical earth, 157–9
SNREI earth, 111–15
SOFAR channel (SOund Fixing and Ranging), 70
solidus, 204, 209
source location, 419–20
source time function, 222, 230, 235, 258–9
South American plate, deformation, 339–40,
342–3, 365
Southern California Seismographic Network, 410
Soviet Union, nuclear testing, 26–7
spatial aliasing, 407n7
spatial eigenfunction, 36
spatial frequency, 31
spectral resonance peaks, attenuation, 193–4
sphere, modes of, 101–11
spherical coordinates, 462–3
axes, 465
distance and azimuth, 463–5
vector operators, 465–6
spherical earth, ray paths and travel times, 157–9
spherical harmonics, 103–4
spherical waves, 55–6
spheroidal modes, 106, 109–10
spinel, transition from olivine, 205–6, 311,
316–18
Spitak (Armenia) earthquake (1988), 12–13, 15
splitting, mode, 104, 114–15
SPO see shape-preferred orientation anisotropy
spread, statistical, 393, 420
spreading centers, 286, 298–307
mid-ocean ridges and transforms, 288, 298–9,
305–7
oceanic lithosphere formation, 299–305
stable sliding, 357
stacking, 391–7
Standard for the Exchange of Earthquake Data
(SEED), 408
standard linear solid, 196
standing waves, 36, 101, 466
starting model, 417
static displacements, faults, 254–6
seismic phases, S waves (continued):
ScS 670 S, 176
S diff , 58, 86, 108–9, 176, 182–3
S diff200 S diff , 176
S diff400 S diff , 176
S diff670 S diff , 176
SdS, 172–3
S g , 122
SKS, 58, 86, 109, 163–5, 168, 174, 181–2
SKKS, 58, 86, 163–5, 168
SKKKS, 168
S n , 122
SPdKS, 174
sPS, 165–6
sS, 3, 108, 163–4, 176
sScS, 3, 108, 176
sScS2, 3
sScS3, 3
sScS4, 3
sS diff , 58
SS, 3, 58, 86, 108, 163–7, 176, 383–4, 395, 433
sSKS, 164
SSS, 3, 86, 108, 164–6, 176
sSS, 108
S4, 3, 86, 164, 166, 176
S 220 S, 176
S 400 S, 176
S 410 S, 395
S 520 S, 395
S 660 S, 395
S 670 S, 176
S5, 166, 176
seismic ray, 6, 65
seismic section, 143–4
seismic slip
continental deformation zones, 340–1
subduction zones, 323–4
seismic sources, 1, 4, 141
air gun, 148–9
double couples, 220, 240, 242
equivalent body force, 220, 240
exploding reflectors, 152
explosive, 245
force couples, 241–2
isotropic, 245, 247
magnitudes and moment, 4, 263–6
moment tensors, 239–51
moving point, 231
point, 56, 152–3
scaling relations, 268–9
single forces, 240–1
spectra, 266–8
stress drop, 269–73
time function, 222, 230, 235, 258–9
Vibroseis unit, 149–52
seismic spectrum, 59
seismic strain rate tensor, 341
seismic velocity see velocity
seismic waves
attenuation, 114, 185–98
introduction to, 1–3
in layered medium, 62–86
phases, 2–3
plane waves, 54–5, 61
ray paths, 2, 65, 120–1
seismic wave equation, 53–4
signal filtering, 369
in spherical earth, 157–62
spherical waves, 55–6
string waves, 29–38
travel times, 60–1, 119–20
see also body waves; surface waves
seismicity
deep, 289–90, 312, 319–22
geographic distribution, 9–10, 289
temporal distribution, 11, 274–6
seismograms
common midpoint (CMP) stacking, 141–4
cross-correlation, 383–5
data processing sequence, 156–7
data sampling, 385–7
digital, 405–7
Fourier analysis, 369–77
introduction to, 1–3
linear systems, 377–85
mode observation, 110
multichannel, 140–1
P and S waves, 57–8, 60–1
receivers, 141
record sections, 122
rotated, 57–8
stacking, 391–7
synthetic, 111, 383
seismological networks
arrays, 407, 408–9
global, 407–8
regional, 407, 410–12
seismometers, 1
analog, 401
arrays, 408–9
broadband, 404
damped harmonic oscillator, 190–1, 398–9
digital, 403–7
earth noise reduction, 400
electromagnetic, 401–2
force-feedback, 403
IDA gravimeter, 403
networks, 407–12
ocean bottom, 408
response, 229–30, 379, 401–2
strainmeter, 404, 406
Streckheisen, 404
strong-motion, 404
time recording, 405
types of, 141, 385, 398, 400–5
WWSSN, 402–3
Wood–Anderson, 263
seismometry
definition, 398
development of, 401
seismoscopes, 400–1
self-similarity, 274
shadow zone, 161, 167–8
Shah function, 385
shape-preferred orientation (SPO) anisotropy, 177
shear modulus, 50
shear stresses, 40, 43–5, 350–1
shear wave splitting, 181–2
shear waves see S waves
shift theorems, 374
shock wave, from explosion, 245
Sierra Nevada, crustal structure, 129–30
signal enhancement, reflection seismology, 145–7
signal processing, 369
signals, finite length, 380–3
silent earthquakes, 262
sinc function, 73, 381, 383
single forces, 240–1
single-couple source, 241
singlets, normal mode, 104, 114
660-km discontinuity, 163–4, 171, 202–3, 205–7,
315–20
slab pull, 314, 315, 324, 330
slabs, subducting, 286, 308–21
slant stacks, 147, 396
Slichter mode, 106
slider model, 360
sliding, stick-slip, 359–64
sliding friction, 352
slip
aseismic, 262, 324, 340
at faults, 218, 254–6, 262–3
seismic, 323–4
slip partitioning, 322
slip vector, 218, 228, 243, 293
slow earthquakes, 271
slowness
horizontal, 69
intercept-slowness, 137–40
and ray parameter, 69–70
vector, 69
vertical, 69
SLR see Satellite Laser Ranging
slump earthquakes, 241, 346–7
Snell’s law
and Fermat’s principle, 71
and Huygens’ principle, 72–3
P–SV waves, 66–7
SH waves, 68–9
in spherical earth, 157–9
SNREI earth, 111–15
SOFAR channel (SOund Fixing and Ranging), 70
solidus, 204, 209
source location, 419–20
source time function, 222, 230, 235, 258–9
South American plate, deformation, 339–40,
342–3, 365
Southern California Seismographic Network, 410
Soviet Union, nuclear testing, 26–7
spatial aliasing, 407n7
spatial eigenfunction, 36
spatial frequency, 31
spectral resonance peaks, attenuation, 193–4
sphere, modes of, 101–11
spherical coordinates, 462–3
axes, 465
distance and azimuth, 463–5
vector operators, 465–6
spherical earth, ray paths and travel times, 157–9
spherical harmonics, 103–4
spherical waves, 55–6
spheroidal modes, 106, 109–10
spinel, transition from olivine, 205–6, 311,
316–18
Spitak (Armenia) earthquake (1988), 12–13, 15
splitting, mode, 104, 114–15
SPO see shape-preferred orientation anisotropy
spread, statistical, 393, 420
spreading centers, 286, 298–307
mid-ocean ridges and transforms, 288, 298–9,
305–7
oceanic lithosphere formation, 299–305
stable sliding, 357
stacking, 391–7
Standard for the Exchange of Earthquake Data
(SEED), 408
standard linear solid, 196
standing waves, 36, 101, 466
starting model, 417
static displacements, faults, 254–6