Handbook of Geomathematics pp 1887-1904 | Cite as
Transmission Tomography in Seismology
Abstract
This chapter summarizes three important methods for seismic transmission tomography: the interpretation of delays in onset times of seismic phases using ray theory, of cross-correlation delays using finite-frequency methods, and of full waveforms using adjoint techniques. Delay-time techniques differ importantly in one key aspect from full waveform inversions in that they are more linear. The inverse problem for onset times is usually small enough that it can be solved by matrix inversion; for waveform inversions gradient searches are generally needed, and for cross-correlation delays the solver depends on the size of the problem.
Onset times can simply be interpreted using the approximations of geometrical optics (ray theory). For cross-correlation delays one can use ray theory to compute the linearized dependency on model perturbations in a volume around the ray, if the observed phase travels a well-identified raypath. However, for diffracted pulses or headwaves, numerical solvers for the wavefield are needed. This is also the case for waveform inversions. Whatever the technique that is used, the resulting linearized system is usually underdetermined and needs to be regularized.
Progress in the near future is to be expected from efforts to densify the network of seismometers and extending it to the oceanic domain, as well as from the continued growth in the power of supercomputing that will soon push waveform inversions to embrace the full frequency range of observed seismic signals.
Keywords
Seismic Velocity Lower Mantle Seismic Tomography Waveform Inversion Spectral Element MethodReferences
- Bois P, la Porte M, Lavergne M, Thomas G (1971) Essai de determination automatique des vitesses sismiques par mesures entre puits. Geophys Prospect 19:42–81CrossRefGoogle Scholar
- Dahlen FA, Hung S-H, Nolet G (2000) Fréchet kernels for finite-frequency traveltimes – I. theory. Geophys J Int 141:157–174CrossRefGoogle Scholar
- Dahlen FA, Tromp J (1998) Theoretical global seismology. Princeton University Press, PrincetonGoogle Scholar
- Fichtner A, Bunge H-P, Igel H (2006) The adjoint method in seismology I. Theory. Phys. Earth Planet Inter 157:86–104CrossRefMATHGoogle Scholar
- Fletcher R, Reeves C (1964) Function minimizationby conjugate gradients. Comput J 7:149–154MathSciNetCrossRefMATHGoogle Scholar
- Forte AM, Sandrine Q, Moucha R, Simmons NA, Grand SP, Mitrovica JX, Rowley DB (2010) Joint seismic-geodynamic-mineral physical modelling of African geodynamics: a reconciliation of deep-mantle convection with surface geophysical constraints. Earth Planet Sci Lett 295:329–341CrossRefGoogle Scholar
- Fukao Y, Widiyantoro S, Obayashi M (2001) Stagnant slabs in the upper and lower mantle transition region. Rev Geophys 39:291–323CrossRefGoogle Scholar
- Irving JCE, Deuss A (2011) Hemispherical structure in inner core velocity anisotropy. J Geophys Res 116:B04307Google Scholar
- Kawai K, Takeuchi N, Geller RJ (2006) Complete synthetic seismograms up to 2 Hz for transversely isotropic spherically symmetric media. Geophys J Int 164:411–424CrossRefGoogle Scholar
- Lawrence JF, Shearer PM (2008) Imaging mantle transition zone thickness with SdS-SS finite-frequency sensitivity kernels. Geophys J Int 174:143–158CrossRefGoogle Scholar
- Loris I (2015) Numerical algorithms for non-smooth optimization applicable to seismic recovery. In: Freeden et al. (Eds) Handbook of Geomathematics, 2nd Ed., SpringerGoogle Scholar
- Luo Y, Schuster GT (1991) Wave-equation travel time tomography. Geophysics 56:645–653CrossRefGoogle Scholar
- Mercerat D, Nolet G (2012) Comparison of ray-based and adjoint-based sensitivity kernels for body-wave seismic tomography. Geophys Res Lett 39:L12301CrossRefGoogle Scholar
- Mercerat ED, Nolet G (2013) On the linearity of cross-correlation delay times in finite-frequency tomography. Geophys J Int 192:681–687CrossRefGoogle Scholar
- Montelli R, Nolet G, Dahlen FA, Masters G (2006) A catalogue of deep mantle plumes: new results from finite-frequency tomography. Geochem Geophys Geosys (G3) 7:Q11007Google Scholar
- Montelli R, Nolet G, Dahlen FA, Masters G, Engdahl ER, Hung S-H (2004) Finite frequency tomography reveals a variety of plumes in the mantle. Science 303:338–343CrossRefGoogle Scholar
- Nissen-Meyer T, Dahlen FA, Fournier A (2007) Spherical-earth Fréchet sensitivity kernels. Geophys J Int 168:1051–1066CrossRefGoogle Scholar
- Nolet G (2008) A breviary of seismic tomography. Cambridge University Press, CambridgeCrossRefMATHGoogle Scholar
- Tibuleac IM, Nolet G, Michaelson C, Koulakov I (2003) P wave amplitudes in a 3-D Earth. Geophys J Int 155:1–10CrossRefGoogle Scholar
- Tromp J, Tape C, Liu Q (2005) Seismic tomography, adjoint methods, time reversal and banana-doughnut kernels. Geophys J Int 160:195–216CrossRefGoogle Scholar
- Zhao L, Jordan TH, Chapman CH (2000) Three-dimensional Fréchet kernels for seismic delay times. Geophys J Int 141:558–576CrossRefGoogle Scholar