Index 493
landslides
caused by earthquakes, 20
as seismic sources, 241
Laplacian, vector field, 461–2, 466
Large Aperture Seismic Array (LASA), 409
lateral spreading, 20
lattice-preferred orientation (LPO) anisotropy,
177
layered medium
dipping, 123–6
as earth model, 62–3
plane waves in, 62–86
refraction seismology, 120–3
least-squares solution, 418
left-lateral slip, 218
Legendre polynomials, 103
Lehmann, Inge, 168n6
Lesser Antilles, travel time tomography, 432
lid see seismic lithosphere
light, analogies for seismic waves, 2, 32n3, 38n6,
56–7, 61n1, 67, 70n2, 74, 96, 185, 189n3,
194n5, 231n2
linear elasticity, 48
linear superposition, 34, 377
linear systems, 377–85
convolution and deconvolution, 379–80
linear vector space, 450
linear velocity, plate motions, 290
liquefaction, caused by earthquakes, 20
lithosphere, 170, 286–7
anisotropy, 180–2
strength of, 357–9
see also oceanic lithosphere
lithostatic stress, 45–6
Loma Prieta earthquake (1989), 7, 12–13, 15, 24,
282, 293
aftershocks, 277
damage caused by, 13, 18
ground motion, 62
liquefaction, 20
source parameters, 265–7
Long Beach earthquake (1933), 17
Long Valley caldera, 246, 334
longitudinal waves, 57
Love, A. E. H., 86n1, 110
Love waves
definition, 86–7
dispersion, 91–3, 96–7
focal mechanisms, 235–9
layer over halfspace, 90–3, 102
and torsional modes, 107, 109
low-velocity zone (LVZ), 99, 170, 204, 303, 358,
435
lower focal hemisphere, 222
lower mantle see mantle
LPO see lattice-preferred orientation anisotropy
lunar seismology, 210–11
LVZ see low-velocity zone
magma chamber, 186, 246, 305
magnesiowustite, 205, 316
magnetic reversals, 293
magnitude, earthquake
body wave, 264
of earthquakes, 4, 11, 263–6
frequency–magnitude relations, 274–7
local, 263
moment, 266
and radiated energy, 273
saturation, 265, 268
surface wave, 264
uncertainties in, 7, 266
magnitude of vectors, 446
mainshock, 277
mantle
anisotropy, 182–4
attenuation, 198, 435–7
boundary with crust (Moho), 122, 128–31
chemical composition of, 204–7
convection system, 286–7
discontinuities, 170–1
lower mantle structure, 171–4
regions of, 162
temperature of, 204
upper mantle structure, 169–71
viscosity of, 331–2, 350, 355–7
see also core–mantle boundary; D′′ region
mantle plume hypothesis, 297
mantle waves, 251
Mars, 211, 287–8
master event methods, earthquake location, 424
mathematical techniques, 443
matrix
adjoint, 451
cofactor, 452
computer solutions of linear equations, 453–4
diagonalization and decomposition, 426–7,
456–7
definitions, 450–1
determinant, 451–2
eigenvalues and eigenvectors, 456–7
generalized inverse 247, 418, 426–7
Hermitian, 451
identity, 451
invariants, 43, 457
inverse, 452
linear equations, 452–3
orthogonal, 452
symmetric, 451
transpose, 451
maximum time path, 71–2, 164–6
Maxwell relaxation time, 355–6
Maxwell viscoelastic material, 355
mean recurrence time, 278
Mediterranean collision zone, 337–9
megaton, energy unit, 11
Mercury, 211
meridians, 463
metastability, 316n3
meteor impacts, as seismic source, 241
meteorites, composition of, 209
mesosphere, 319
Mexico City earthquake (1985), 12, 18
mica, anisotropy, 179–80
microplates, 307
microearthquakes, 299, 305
microseismicity, 25
microseisms, 400
Mid-Atlantic ridge, 298–9
mid-ocean ridges, 286–8, 298–9, 305–7
migration, reflection seismology, 152–6
Millikan, R., 7
minerals
anisotropy, 179–80
crust and upper mantle, 130–4
phase changes and deep earthquakes, 317–18
phase changes and intermediate earthquakes, 321
in subducting slabs, 315–17
in transition zone, 205–7
minimum time path, 71–2, 164–6
mode–wave duality, 101
model resolution matrix, 427
models
of the earth, 62–3, 119, 162
in inverse problems, 415–16
plate motions, 8, 293–4
use of, 5–9
modes, normal see normal modes
Modified Mercalli scale, 14–16
Moho (Mohorovicic discontinuity), 75
discovery of, 122
reflection and transmission at, 82–4, 122
geological composition, 130–1
waveforms, effects on, 127–8, 130
Mohorovicic, Andrija, 122
Mohr envelopes, 353
Mohr’s circle, 350–4
moment, see seismic moment
moment magnitude, 266, 273
moment tensor, seismic, 239–51
compensated linear vector dipoles (CLVDs),
245–6
interpretation of, 249–51
inversion, 246–9
isotropic, 245
stress (P, T, B) axes, 243–4
moon
moonquakes, 210
scattering of seismic waves, 189–90
velocity structure, 210–11
Mt. St. Helens, explosion, 240–1
moveout, 134, 142
multichannel data geometry, reflection seismology,
140–1
multipathing
seismic waves, 185, 187–8
tsunami, 100
multiplet, 104, 114–15, 184, 194, 388
music of the spheres, 110n7
namazu (catfish), 322n5
Nankai trough, 322–3
Nazca plate, 144, 305, 307, 339–40
networks see seismological networks
New Madrid earthquakes (1811 & 1812) and
seismicity, 12, 14–16, 274, 343–6
Newtonian fluids, 356
Newton’s second law of motion, 29, 38, 47, 101
Niigata earthquake (1964), 20
Ninetyeast ridge, 329
Nisqually earthquake (2001) 334
NMO see normal moveout
nodal lines, 104–6
nodal planes, 219, 222, 224, 226–9
nodal surfaces, 105–7
nodes, 92, 105
noise, in seismograms, 141, 145, 369, 383, 395, 400
noncausality, 195, 378, 405
nonlinear tomography, 433
normal fault earthquakes, 218–19, 298–9, 307,
328–9, 334
surface waves, 236
normal modes of the earth, 101–15
attenuation, 114, 434–7
dispersion, 107–9
inverse problem for, 434–7
radial, 106
of a sphere, 101–11
spheroidal, 106–10
splitting, 114–15
landslides
caused by earthquakes, 20
as seismic sources, 241
Laplacian, vector field, 461–2, 466
Large Aperture Seismic Array (LASA), 409
lateral spreading, 20
lattice-preferred orientation (LPO) anisotropy,
177
layered medium
dipping, 123–6
as earth model, 62–3
plane waves in, 62–86
refraction seismology, 120–3
least-squares solution, 418
left-lateral slip, 218
Legendre polynomials, 103
Lehmann, Inge, 168n6
Lesser Antilles, travel time tomography, 432
lid see seismic lithosphere
light, analogies for seismic waves, 2, 32n3, 38n6,
56–7, 61n1, 67, 70n2, 74, 96, 185, 189n3,
194n5, 231n2
linear elasticity, 48
linear superposition, 34, 377
linear systems, 377–85
convolution and deconvolution, 379–80
linear vector space, 450
linear velocity, plate motions, 290
liquefaction, caused by earthquakes, 20
lithosphere, 170, 286–7
anisotropy, 180–2
strength of, 357–9
see also oceanic lithosphere
lithostatic stress, 45–6
Loma Prieta earthquake (1989), 7, 12–13, 15, 24,
282, 293
aftershocks, 277
damage caused by, 13, 18
ground motion, 62
liquefaction, 20
source parameters, 265–7
Long Beach earthquake (1933), 17
Long Valley caldera, 246, 334
longitudinal waves, 57
Love, A. E. H., 86n1, 110
Love waves
definition, 86–7
dispersion, 91–3, 96–7
focal mechanisms, 235–9
layer over halfspace, 90–3, 102
and torsional modes, 107, 109
low-velocity zone (LVZ), 99, 170, 204, 303, 358,
435
lower focal hemisphere, 222
lower mantle see mantle
LPO see lattice-preferred orientation anisotropy
lunar seismology, 210–11
LVZ see low-velocity zone
magma chamber, 186, 246, 305
magnesiowustite, 205, 316
magnetic reversals, 293
magnitude, earthquake
body wave, 264
of earthquakes, 4, 11, 263–6
frequency–magnitude relations, 274–7
local, 263
moment, 266
and radiated energy, 273
saturation, 265, 268
surface wave, 264
uncertainties in, 7, 266
magnitude of vectors, 446
mainshock, 277
mantle
anisotropy, 182–4
attenuation, 198, 435–7
boundary with crust (Moho), 122, 128–31
chemical composition of, 204–7
convection system, 286–7
discontinuities, 170–1
lower mantle structure, 171–4
regions of, 162
temperature of, 204
upper mantle structure, 169–71
viscosity of, 331–2, 350, 355–7
see also core–mantle boundary; D′′ region
mantle plume hypothesis, 297
mantle waves, 251
Mars, 211, 287–8
master event methods, earthquake location, 424
mathematical techniques, 443
matrix
adjoint, 451
cofactor, 452
computer solutions of linear equations, 453–4
diagonalization and decomposition, 426–7,
456–7
definitions, 450–1
determinant, 451–2
eigenvalues and eigenvectors, 456–7
generalized inverse 247, 418, 426–7
Hermitian, 451
identity, 451
invariants, 43, 457
inverse, 452
linear equations, 452–3
orthogonal, 452
symmetric, 451
transpose, 451
maximum time path, 71–2, 164–6
Maxwell relaxation time, 355–6
Maxwell viscoelastic material, 355
mean recurrence time, 278
Mediterranean collision zone, 337–9
megaton, energy unit, 11
Mercury, 211
meridians, 463
metastability, 316n3
meteor impacts, as seismic source, 241
meteorites, composition of, 209
mesosphere, 319
Mexico City earthquake (1985), 12, 18
mica, anisotropy, 179–80
microplates, 307
microearthquakes, 299, 305
microseismicity, 25
microseisms, 400
Mid-Atlantic ridge, 298–9
mid-ocean ridges, 286–8, 298–9, 305–7
migration, reflection seismology, 152–6
Millikan, R., 7
minerals
anisotropy, 179–80
crust and upper mantle, 130–4
phase changes and deep earthquakes, 317–18
phase changes and intermediate earthquakes, 321
in subducting slabs, 315–17
in transition zone, 205–7
minimum time path, 71–2, 164–6
mode–wave duality, 101
model resolution matrix, 427
models
of the earth, 62–3, 119, 162
in inverse problems, 415–16
plate motions, 8, 293–4
use of, 5–9
modes, normal see normal modes
Modified Mercalli scale, 14–16
Moho (Mohorovicic discontinuity), 75
discovery of, 122
reflection and transmission at, 82–4, 122
geological composition, 130–1
waveforms, effects on, 127–8, 130
Mohorovicic, Andrija, 122
Mohr envelopes, 353
Mohr’s circle, 350–4
moment, see seismic moment
moment magnitude, 266, 273
moment tensor, seismic, 239–51
compensated linear vector dipoles (CLVDs),
245–6
interpretation of, 249–51
inversion, 246–9
isotropic, 245
stress (P, T, B) axes, 243–4
moon
moonquakes, 210
scattering of seismic waves, 189–90
velocity structure, 210–11
Mt. St. Helens, explosion, 240–1
moveout, 134, 142
multichannel data geometry, reflection seismology,
140–1
multipathing
seismic waves, 185, 187–8
tsunami, 100
multiplet, 104, 114–15, 184, 194, 388
music of the spheres, 110n7
namazu (catfish), 322n5
Nankai trough, 322–3
Nazca plate, 144, 305, 307, 339–40
networks see seismological networks
New Madrid earthquakes (1811 & 1812) and
seismicity, 12, 14–16, 274, 343–6
Newtonian fluids, 356
Newton’s second law of motion, 29, 38, 47, 101
Niigata earthquake (1964), 20
Ninetyeast ridge, 329
Nisqually earthquake (2001) 334
NMO see normal moveout
nodal lines, 104–6
nodal planes, 219, 222, 224, 226–9
nodal surfaces, 105–7
nodes, 92, 105
noise, in seismograms, 141, 145, 369, 383, 395, 400
noncausality, 195, 378, 405
nonlinear tomography, 433
normal fault earthquakes, 218–19, 298–9, 307,
328–9, 334
surface waves, 236
normal modes of the earth, 101–15
attenuation, 114, 434–7
dispersion, 107–9
inverse problem for, 434–7
radial, 106
of a sphere, 101–11
spheroidal, 106–10
splitting, 114–15