Throughout the world, large aquifers occur in fractured siliciclastic rocks, primarily in sandstones and secondarily in sandstone-shale intercalations. Fractures in these rocks can result in extremely high velocity and volume of fluid flow, thus are critical for evaluating groundwater systems. There are many structural relationships among the various fracture types such as deformation bands, joints, and large faults, and each fracture type has a wide range of physical properties. This book focusses on the properties most relevant to groundwater science such as permeability, porosity, as well as fracture length and frequency (density).
Due to the variability and complex influence of siliciclastic rock fractures on groundwater flow, characterizing such fractures poses a great challenge to hydrogeologists and engineers. Although remote detection methods with limited resolution are available for fracture characterization, gaining direct knowledge of failure structures in siliciclastic rocks, including architecture, distribution, and fluid flow properties is effective for assessing their impact on groundwater flow.