Foundations Of Anisotropy For Exploration Seismics (handbook Of Geophysical Exploration: Seismic Exploration)

Over the last few years, anisotropy has become a ''hot topic'' in seismic exploration and seismology. It is now recognised that geological media deviate more or less from isotropy. This has consequences for acquisition, processing and interpretation of seismic data and also helps determine the cause of anisotropy and adds to our knowledge concerning the structure of the medium at scales beyond the resolution of the seismic method. This volume addresses the theoretical foundations of wave propagation in anisotropic media at an easily accessible level. The treatment is not restricted to exploration seismology. The book commences with fundamental material and covers the description of wave propagation in anisotropic conditions by means of slowness and wave surfaces. It continues to explore the theory of elasticity, the interaction of elasticity and material symmetry and conditions imposed by the stability of the medium. Wave propagation in general anisotropic solids are discussed referring in particular to singular and longitudinal directions. Slowness and wave surfaces in transversely isotropic media and in the planes of symmetry of orthorhombic media is presented and then moves on to wave propagation in orthorhombic media by means of ''squared slowness surfaces''. The latter part of the book deals with layer-induced anisotropy showing how a particular internal structure of a medium leads to anisotropy and how much of this structure can be recovered by ''inversion'' of the modelling algorithm. A few fundamental aspects of exploration seismology are also discussed. The final chapter discusses how concepts which were developed by Kelvin, but only recently understood, can be utilised to determine the symmetry class and orientation of an elastic medium Content: Handbook of Geophysical Exploration Page ii Front Matter Page iii Copyright page Page iv Preface Pages v-x Chapter 1 - Fundamentals Pages 1-16 Chapter 2 - Tools for the description of wave propagation under piece-wise homogeneous anisotropic conditions Pages 17-19,21-57 Chapter 3 - Elasticity Pages 59-95,97-126 Chapter 4 - Elastic waves — the dispersion relation and some generalities about slowness- and wave surfaces Pages 127-129,131-181 Chapter 5 - Stability constraints Pages 183,185-194 Chapter 6 - One-parameter expressions for the slowness surfaces of transversely isotropic media and the slowness curves in the planes of symmetry of orthorhombic media Pages 195-221,223-224 Chapter 7 - One-parameter expressions for the intersection of wave surfaces with the symmetry planes of orthorhombic media Pages 225-234 Chapter 8 - Squared slowness surfaces and squared slowness curves Pages 235-287,289-295 Chapter 9 - Causes of anisotropy: periodic fine layering Pages 297-345 Chapter 10 - Anisotropy and seismic exploration Pages 347-392 Chapter 11 - Eigentensors of the elastic tensor and their relationship with material symmetry Pages 393-470 References Pages 471-482 Index Pages 483-486 Addresses the theoretical foundations of wave propagation in anisotropic media. Not confined to exploration seismology, topics covered include the description of wave propagation in anisotropic conditions by means of slowness and wave surfaces, the theory of elasticity and layer-induced anisotropy.