The response of a steel moment resisting frame (MRF) depends on the specifications of its main components, namely the columns, beams and connections. One important connection element which can significantly affect frame behavior is the panel zone (PZ). The PZ is described to be an element mainly subjected to shear stresses and its failure mode is often governed by shear yielding. Several analyt...

The relationship between plate boundary forces and the observed stress field in the Pacific Northwest is established using numerical niodels of continental deformation. Because the orientation of the greatest horizontal principal stress throughout the Pacific Northwest differs considerably from the direction of convergence between the Juan de Fuca and North American plates. the relationship haw...

Though remarkably robust, articular cartilage becomes susceptible to damage at high loading rates, particularly under shear. While several studies have measured the local static and steady-state shear properties of cartilage, it is the local viscoelastic properties that determine the tissue's ability to withstand physiological loading regimens. However, measuring local viscoelastic properties r...

The large amplitude oscillations of the shape of Neptune's Great Dark Spot are well reproduced by simple dynamical models of an isolated vortex embedded in a background shear flow. From the time series of the aspect ratio and inclination of the vortex values are estimated for the background shear and the mean vorticity of the Great Dark Spot, and a lower bound is placed on the value of the Ross...

Seismic anisotropy and P-wave delays in New Zealand imply widespread deformation in the underlying mantle, not slip on a narrow fault zone, which is characteristic of plate boundaries in oceanic regions. Large magnitudes of shear-wave splitting and orientations of fast polarization parallel to the Alpine fault show that pervasive simple shear of the mantle lithosphere has accommodated the cumul...

We study strain localization as an enhanced velocity weakening mechanism on earthquake faults. Fault friction is modeled using Shear Transformation Zone (STZ) Theory, a microscopic physical model for non-affine rearrangements in granular fault gouge. STZ Theory is implemented in spring slider and dynamic rupture models of faults. We compare dynamic shear localization to deformation that is unif...

We report molecular dynamics simulations of shear in a biomimetic hydroxyapatite-collagen composite. Our model exhibits elastic properties fully dominated by the inorganic component. However, beyond the elastic regime the biomolecules along with the hierarchical nature of the composite account for the formation of structure-inherent slip zones. These accommodate shear without compromising the o...

A primary goal in seismology is to identify constraints arising from the small scale physics of friction and fracture that can provide bounds on seismic hazard and ground motion at the fault scale. Here we review the multi-scale earthquake rupture problem and describe a physical model for the deformation of amorphous materials such as granular fault gouge. The model is based on Shear Transforma...

We conducted permeability measurements of basalt sampled from an exhumed ancient fault zone in the Cretaceous Shimanto accretionary complex in Japan, in order to investigate permeability structure and evolution following shear failure. Permeability showed a strong reduction with increase in the e#ective confining pressure and temperature. Rapid sealing at elevated temperatures was observed duri...