Recent advances in subseafloor hydrogeology: focus on basement-sediment interactions, subduction zones, and continental slopes

Focused, interdisciplinary research in the subseafloor environment has advanced our understanding of fluid flow paths and the interrelationship between fluid pressure and deformation, heat flow, and diagenesis. Recent investigations in the Pacific Ocean, the Gulf of Mexico, and the North Sea provide examples of high rates of fluid flow in the permeable basement, with the flow affecting properties of overlying sediments. There are also some indications that flow could continue into subduction. Studies on continental slopes provide evidence for sedimentation-driven overpressures that can destabilize slopes. These studies particularly emphasize the contributions of lateral flow driven by uneven loading. Similarly, evidence continues to build that stratigraphic horizons and faults help to dewater subduction zones. A recent development is the monitoring of pore pressure, temperatures, flow, and fluid chemistry, which aids the understanding of transient behavior and response to strain events.