Faults are primary focuses of both fluid migration and deformation in the upper crust. The recognition that faults are typically heterogeneous zones of deformed material, not simple discrete fractures, has fundamental implications for the way geoscientists predict fluid migration in fault zones, as well as leading to new concepts in understanding seismic/aseismic strain accommodation. This book captures current research into understanding the complexities of fault-zone internal structure, and their control on mechanical and fluid-flow properties of the upper crust. A wide variety of approaches are presented, from geological field studies and laboratory analyses of fault-zone and fault-rock properties to numerical fluid-flow modelling, and from seismological data analyses to coupled hydraulic and rheological modelling. The publication aims to illustrate the importance of understanding fault-zone complexity by integrating such diverse approaches, and its impact on the rheological and fluid-flow behaviour of fault zones in different contexts.

Faults are primary focuses of both fluid migration and deformation in the upper crust. The recognition that faults are typically heterogeneous zones of deformed material, not simple discrete fractures, has fundamental implications for the way geoscientists predict fluid migration in fault zones, as well as leading to new concepts in understanding seismic/aseismic strain accommodation. This book captures current research into understanding the complexities of fault-zone internal structure, and their control on mechanical and fluid-flow properties of the upper crust.

Interest in the architecture and fluid flow potential of fault zones in basalt sequences has intensified over recent years, due to their applications in the hydrocarbon industry and CO2 storage. In this study, field mapping is combined with micro-structural analyses and flow modelling to evaluate fault growth, evolution, fluid-rock interactions, and permeability changes over time in faults in basalt sequences. Twelve brittle fault zones cutting basalt sequences in the North Atlantic Igneous Province were studied. This study finds that fault architecture is ultimately controlled by displacement and juxtaposition. Self-juxtaposed faults (i.e. basalt faulted against itself) are characterised by wide zones of brecciation, cataclasis, fracturing, mineralisation and alteration. Non self-juxtaposed faults (i.e. basalt faulted against an inter-lava unit) are characterised by relatively narrow principal slip zones, filled with clay smears or clay-rich gouge derived from inter-lava beds. This study also finds that brittle deformation of basalts at the grain scale is mineralogy dependent. Fe-Ti oxides and pyroxenes deform by intragranular fracturing and grain size reduction, whereas olivines and feldspars are susceptible to replacement by clay and zeolites. Fault rock bulk chemistries are likely to differ from their host rocks, and this is controlled by secondary mineral formation, with zeolite and clay minerals playing an important role. Flow modelling in this study shows that controls on along- and across-fault fluid flow can significantly change fault zone bulk permeability over time, as a result of mineralisation and alteration of the fault zone as it evolves. The results from this study are used to propose a model for how fault strength, fault-related alteration, and permeability change over time in fault zones in basalt sequences. Results highlight the impact that fault-related alteration could have on CO2 storage. A predictive model for fault structure at depth, developed from this study's findings, is presented for fault zones in basalt sequences, which has particular relevance to the hydrocarbon and CO2 industry.

Considerable progress has been made recently in quantifying geometrical and physical properties of fault surfaces and adjacent fractured and granulated damage zones in active faulting environments. There has also been significant progress in developing rheologies and computational frameworks that can model the dynamics of fault zone processes. This volume provides state-of-the-art theoretical and observational results on the mechanics, structure and evolution of fault zones. Subjects discussed include damage rheologies, development of instabilities, fracture and friction, dynamic rupture experiments, and analyses of earthquake and fault zone data.

This market-leading textbook has been fully updated in response to extensive user feedback. It includes a new chapter on joints and veins, additional examples from around the world, stunning new field photos, and extended online resources with new animations and exercises. The book's practical emphasis, hugely popular in the first edition, features applications in the upper crust, including petroleum and groundwater geology, highlighting the importance of structural geology in exploration and exploitation of petroleum and water resources. Carefully designed full-colour illustrations work closely with the text to support student learning, and are supplemented with high-quality photos from around the world. Examples and parallels drawn from practical everyday situations engage students, and end-of chapter review questions help them to check their understanding. Updated e-learning modules are available online (www.cambridge.org/fossen2e) and further reinforce key topics using summaries, innovative animations to bring concepts to life, and additional examples and figures.

The international Mont Terri rock laboratory in Switzerland plays a central role in the safety and construction of deep geological nuclear repositories in clay formations. The laboratory has developed and refined a range of new measurement and evaluation methods: it has e.g. advanced the determination of rock parameters using innovative borehole geophysics, improved the methodology for characterizing pore-water and microbial activity in claystones, and greatly improved our understanding of diffusion and retention processes of radionuclides in and through claystones. The methods and insights described in this compendium can also be applied to low-permeability rocks at various sites around the globe, and in other fields of application.