We investigate global variations in the pattern of aftershock area expansion associated with large subduction zone earthquakes. The expansion of aftershock areas with time is relatively small in the subduction zones of Alaska, the Aleutians, Mexico, and parts of the Kuriles and South America. These subduction zones are interpreted to be characterized by moderate to strong interplate coupling. I...

S U M M A R Y We use idealized subduction megathrust models to examine aseismic, frictional fault creep throughout the interseismic period. We consider rate-dependent and rateand state-dependent friction. When there is significant post-seismic creep surrounding locations of coseismic slip, the creep rates surrounding an asperity may be lower than the plate convergence rate late in the seismic c...

The shortand long-period body waves of five moderate (M L 5 to 6) earthquakes that took place in the nearshore region of southcentral California between 1969 and 1981 are modeled to obtain the source parameters. Both regional Pnl waveforms and teleseismic P waveforms are used in this analysis. Four of the events are thrust earthquakes with strikes that rotate southwestward as the epicenters mov...

[1] We investigate the ground motion produced by rupture propagation through circular barriers and asperities in an otherwise homogeneous earthquake rupture. Using a threedimensional finite difference method, we analyze the effect of asperity radius, strength, and depth in a dynamic model with fixed rupture velocity. We gradually add complexity to the model, eventually approaching the behavior ...

[1] Bidaily, tidally modulated stick‐slip speed‐ups of the Whillans Ice Plain (WIP) provide insight into glacier dynamics and failure at a naturally repeating fault asperity. We installed a network of continuously operating GPS receivers in 2007 and deployed on‐ice broadband seismometers during the austral summer of 2008 on Whillans Ice Stream (WIS), West Antarctica, and recorded 26 glacier spe...

We present a source model for the beginning of earthquakes based on the Griffith's fracture criterion. The initial state is a critical state of pre-existing circular fault, which is on the verge of instability. After the onset of instability, the fault grows with a progressively increasing rupture speed, satisfying the condition of fracture energy balance at the crack tip. We investigate the di...

The influence of the boundary layer properties on the heat transport in turbulent thermal convection is experimentally investigated in a cell with a rough bottom plate. It is shown that the standard 2/7 exponent of the convective heat flow dependence on the Rayleigh number, usually observed in cell with smooth boundaries, increases if the roughness has power law distributed asperity heights and...

the influence of surface roughness magnitude and direction on dry static friction coefficient between two similar steel samples has been studied through an experiment. a testing apparatus has been designed and fabricated to measure the friction coefficient for a few forms of surface asperity. according to the results of the experiments, dry friction coefficient is affected by both magnitude and...

We predict a strongest size for the contact strength when asperity radii of curvature decrease below 10 nm. The reason for such strongest size is found to be correlated with the competition between the dislocation plasticity and surface diffusional plasticity. The essential role of temperature is calculated and illustrated in a comprehensive asperity size-strength-temperature map taking into ac...