Abstract

Elastic waves are an essential tool for characterizing rock on the laboratory and field scale. In this chapter, methods for interpreting the elastic constants for isotropic and anisotropic fractured rock are given. An overview of the discrete effects of fractures on elastic wave propagation is presented to illustrate behavior not captured by effective medium approaches. Maintaining the discreteness of fractures yields guided modes and energy partitioning that depend on the stiffness of fractures and the signal frequency. Given the complexity of rock and field sites, understanding both effective medium and discrete approaches is required to achieve the best interpretation of the properties of isotropic or anisotropic fractured rock.