Crack Induced Anisotropy And Its Effect On Vertical Seismic Profiling

Rock Testing and Site Characterization

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.

The special issue contains contributions presented at the international workshop Seismic waves in laterally inhomogeneous media IV, which was held at the Castle of Trest, Czech Republic, May 22-27, 1995. The workshop, which was attended by about 100 seismologists from more than 10 countries, was devoted mainly to the current state of theoretical and computational means of study of seismic wave propagation in complex structures. The special issue can be of interest for theoretical, global and explorational seismologists. The first part contains papers dealing with the study and the use of various methods of solving forward and inverse problems in complicated structures. Among other methods, discrete-wave number method, the finite-difference method, the edge-wave supperposition method and the ray method are studied and used. Most papers contained in the second part are related to the ray method. The most important topics are two-point ray tracing, grid calculations of travel times and amplitudes and seismic wave propagation in anisotropic media.

This monograph provides an up-to-date overview on methods and techniques in seismology, with a focus on describing and detecting seismic waves in anisotropic media. The author discusses structural, physical and mechanical aspects of the crust by analyzing earthquake data from field studies, rendering the book a practical reference for researchers in seismology and applied geophysics. Contents: Rock Anisotropy, Fracture and Earthquake Assessment Seismic Wave Propagation in Anisotropic Rocks with Applications to Defining Fractures in Earth Crust Reproducing the Realistic Compressive-tensile Strength Ratio of Rocks using Discrete Element Model Rock Fracture under Static and Dynamic Stress Multiple Linear Regression Analyses on the Relationships among Magnitude, Rupture Length, Rupture Width, Rupture Area, and Surface Displacement PI Algorithm Applied to the Sichuan-Yunnan Region: A Statistical Physics Method for Intermediate-term Medium-range Earthquake Forecast in Continental China Probabilistic Seismic Hazard Assessment for Pacific Island Countries

Seismic measurements take many forms, and appear to have a universal role in the Earth Sciences. They are the means for most easily and economically interpreting what lies beneath the visible surface. There are huge economic rewards and losses to be made when interpreting the shallow crust or subsurface more, or less accurately, as the case may be.

An Introduction to Mining Seismology describes comprehensively the modern methods and techniques used to monitor and study seismicity and rockbursts in mines. Key case histories from various worldwide mining districts clearly illustrate and skillfully emphasize the practical aspects of mining seismology. This text is intended as a handbook for geophysicists and mining and rock mechanics engineers working at mines. It will also serve as an essential reference tool for seismologists working at research institutions on local seismicity not necessarily induced by mining. Presents a comprehensive description of seismicity induced by mining worldwide Provides information on optimum network planning and seismic event location procedures in deep mines Covers a broad array of topics including focal mechanism, moment tensor, and double-couple versus non-double-couple seismic events in mines Includes data on source parameters and scaling relations for seismic events in mines