2006 Volume 115 Issue 3 Pages 326-352
It has long been recognized that unconsolidated or partially consolidated sediments can be intensely deformed during burial, either from gravity-driven subhorizontal extension, or from tectonic shortening. Such deformation can be evaluated in the context of experimental and empirical results from engineering geology literature. We try to summarize this knowledge using several submarine and on-land examples that illustrate the concepts of pore-fluid pressure, shaking, permeability, and consolidation, and are applicable to the interpretation of geologic structures that develop in unconsolidated or partially consolidated sediments. We first review dish, web, and vein structures, scaly clay and liquefaction features, which are typical of unconsolidated or partially consolidated sediments along convergent plate margins. Then, some experimental aspects of permeability test results are applied to fluid flow phenomena in and around accretionary prisms to characterize the role and the importance of fluid flow parallel to the σ2 direction. The results are further applied to explain the concentration of hot springs of a non-volcanic origin along active, strike-slip faults, as well as how seepage along convergent margins occurs in an en echelon pattern on conjugate sets of strike slip faults. Additional experimental work is suggested to develop a better understanding of these geologic structures.
