Fault weakening caused by smectite swelling

Influence of smectite hydration and swelling on atrazine sorption behavior.

Smectites, clay minerals commonly found in soils and sediments, vary widely in their ability to adsorb organic chemicals. Recent research has demonstrated the importance of surface charge density and properties of exchangeable cations in controlling the affinity of smectites for organic molecules. In this study, we induced hysteresis in the crystalline swelling of smectites to test the hypothes...

Dynamic Fault Weakening and Strengthening by Gouge Compaction and Dilatancy in a Fluid-Saturated Fault Zone

Triaxial experiments show that samples of fault gouge deform distinctly differently than those from the adjacent fault damage zone (e.g., Chester and Logan, 1986). Rock samples in the damage zone follow a characteristic elastic-brittle behavior, whereas fault gouge readily compacts and deforms in a more ductile manner. In order to explain the apparent weakness of large plate bounding faults suc...

Frictional strength and strain weakening in simulated fault gouge: Competition between geometrical weakening and chemical strengthening

[1] Despite the importance of hydromechanical effects in fault processes, not much is known about the interplay of chemical and mechanical processes, in part because the conditions are difficult to simulate in the laboratory. We report results from an experimental study of simulated fault gouge composed of rock salt sheared under conditions where pressure solution is known to operate. At slidin...

Chronic lower leg swelling caused by isolated popliteal venous entrapment.

Isolated popliteal vein entrapment is a rare pathologic condition. Mimicking any venous pathology, a high degree of suspicion is mandatory for diagnosis. We describe a case of a 50-year-old woman, suffering from excessive swelling and heaviness of her left leg for more than 15 years. The ascending venography at functional positions of the feet demonstrated the entrapment. A rich collateral veno...

Slip-weakening distance estimated at near-fault stations