Cover image for A breviary of seismic tomography : imaging the interior of the earth and sun
Title:
A breviary of seismic tomography : imaging the interior of the earth and sun
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Publication Information:
New York, NY : Cambridge University Press, 2008
Physical Description:
xiv, 344 p. : ill. ; 26 cm.
ISBN:
9780521882446

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30000010229484 QE538.5 N65 2008 Open Access Book Book
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Summary

Summary

This is the first textbook to cover the essential aspects of the topic at a level accessible to students. While focusing on applications in solid earth geophysics, the book also includes excursions into helioseismology, thereby highlighting the strong affinity between the two fields. The book provides a comprehensive introduction to seismic tomography, including the basic theory of wave propagation, the ray and Born approximations required for interpretation of amplitudes, and travel times and phases. It considers observational features while also providing practical recommendations for implementing numerical models. Written by one of the leaders in the field, and containing numerous student exercises, this textbook is appropriate for advanced undergraduate and graduate courses. It is also an invaluable guide for seismology research practitioners in geophysics and astronomy. Solutions to the exercises and accompanying tomographic software and documentation can be accessed online from www.cambridge.org/9780521882446.


Table of Contents

Prefacep. xi
1 Introductionp. 1
1.1 Early efforts at seismic tomographyp. 2
1.2 Ocean acoustic tomographyp. 3
1.3 Global tomographyp. 3
1.4 Some major discoveriesp. 4
1.5 Helioseismologyp. 7
1.6 Finite-frequency tomographyp. 8
2 Ray theory for seismic wavesp. 11
2.1 The stress tensorp. 11
2.2 Forces in continuous mediap. 12
2.3 Newton's law and the elastodynamic equationsp. 13
2.4 The acoustic wave equationp. 16
2.5 The ray approximationp. 20
2.6 Ray solutions in layered and spherical systemsp. 22
2.7 Geometrical spreadingp. 25
2.8 Rays in an isotropic, elastic Earthp. 26
2.9 Fermat's Principlep. 29
2.10 Huygens, Fresnel and Greenp. 30
2.11 Flow: solar p-waves or ocean acoustic wavesp. 34
2.12 Appendix A: Some elements of Fourier analysisp. 36
3 Ray tracingp. 40
3.1 The shooting methodp. 40
3.2 Ray bendingp. 42
3.3 Other raytracing algorithms for 3D mediap. 46
3.4 Ray-centred coordinatesp. 49
3.5 Dynamic ray tracingp. 50
3.6 Ray tracing on the spherep. 53
3.7 Computational aspectsp. 54
4 Wave scatteringp. 58
4.1 The acoustic Green's functionp. 60
4.2 An acoustic point scattererp. 62
4.3 Green's functions for elastic wavesp. 63
4.4 Green's functions in the ray approximationp. 68
4.5 The Born approximationp. 70
4.6 Scattering of a plane wavep. 73
4.7 The scattering matrixp. 77
4.8 Appendix B: The impulse responsep. 79
5 Body wave amplitudes: theoryp. 82
5.1 Geometrical spreadingp. 82
5.2 The quality factor Qp. 84
5.3 The correspondence principlep. 86
5.4 Attenuating body wavesp. 88
5.5 Scatteringp. 91
6 Travel times: observationsp. 93
6.1 Phase picksp. 96
6.2 Matched filtersp. 100
6.3 Wavelet estimationp. 103
6.4 Differential timesp. 107
6.5 Signal and noisep. 109
6.6 Time-distance analysis in helioseismologyp. 110
7 Travel times: interpretationp. 116
7.1 The ray theoretical interpretationp. 116
7.2 Cross-correlation of seismic arrivalsp. 121
7.3 Forward scatteringp. 125
7.4 Finite frequency sensitivity: a simple examplep. 126
7.5 Finite frequency kernels: generalp. 129
7.6 Alternative arrival time measurementsp. 135
7.7 Alternative methods for kernel computationp. 138
7.8 Computational aspectsp. 139
8 Body wave amplitudes: observation and interpretationp. 145
8.1 Amplitude observationsp. 146
8.2 t* observationsp. 149
8.3 Amplitude healingp. 151
8.4 Boundary topographyp. 152
8.5 Finite-frequency Q tomographyp. 154
9 Nomal modesp. 158
9.1 The discrete spectrump. 159
9.2 Rayleigh's Principlep. 166
9.3 Mode splittingp. 168
9.4 Observations of mode splitsp. 174
10 Surface wave interpretation: ray theoryp. 178
10.1 The theory of surface wavesp. 180
10.2 Love and Rayleigh wavesp. 182
10.3 Measuring fundamental mode dispersionp. 187
10.4 Measuring higher mode dispersionp. 190
10.5 Waveform fittingp. 192
10.6 Partitioned waveform inversion (PWI)p. 194
10.7 Appendix C: Asymptotic theoryp. 197
11 Surface waves: finite-frequency theoryp. 208
11.1 Phase and amplitude perturbationsp. 209
11.2 Practical considerationsp. 214
11.3 Phase velocity maps: an incompatibilityp. 217
12 Model parametrizationp. 219
12.1 Global parametrizationp. 220
12.2 Local parametrizationp. 222
12.3 Numerical considerationsp. 228
12.4 Spectral analysis and model correlationsp. 229
13 Common correctionsp. 233
13.1 Ellipticity correctionsp. 233
13.2 Topographic and bathymetric time correctionsp. 238
13.3 Crustal time correctionsp. 240
13.4 Surface wave correctionsp. 243
13.5 Source correctionsp. 245
13.6 Amplitude corrections for body wavesp. 247
13.7 Dispersion correctionsp. 249
13.8 Instrument responsep. 250
13.9 Clock correctionsp. 253
14 Linear inversionp. 255
14.1 Maximum likelihood estimation and least squaresp. 256
14.2 Alternatives to least squaresp. 260
14.3 Singular value decompositionp. 261
14.4 Tikhonov regularizationp. 265
14.5 Bayesian inferencep. 266
14.6 Information theoryp. 270
14.7 Numerical considerationsp. 272
14.8 Appendix D: Some concepts of probability theory and statisticsp. 275
15 Resolution and error analysisp. 277
15.1 Resolution matrixp. 277
15.2 Backus-Gilbert theoryp. 281
15.3 Sensitivity testsp. 285
16 Anisotropyp. 289
16.1 The elasticity tensorp. 290
16.2 Waves in homogeneous anisotropic mediap. 295
16.3 S-wave splittingp. 296
16.4 Surface wave anisotropyp. 301
17 Future directionsp. 306
17.1 Beyond Bornp. 306
17.2 Adjoint methodsp. 307
17.3 Global coverage of seismic sensorsp. 310
17.4 Helioseismology and astroseismologyp. 312
Referencesp. 313
Author indexp. 334
General indexp. 339