Now showing items 1-20 of 38

• #### A Critical Evaluation of Cohesive Zone Models of Dynamic Fracture ﻿

(EDP Sciences, 2001)
Finite element calculations of dynamic fracture based on embedding cohesive surfaces in a continuum indicate that the predictions are sensitive to the cohesive law used. Simulations were performed on a square block in plane ...
• #### Deformation-Induced Melting in the Margins of the West Antarctic Ice Streams ﻿

(Wiley-Blackwell, 2014)
Flow of glacial ice in the West Antarctic Ice Sheet localizes in narrow bands of fast-flowing ice streams bordered by ridges of nearly stagnant ice, but our understanding of the physical processes that generate this ...
• #### Dilatant Strengthening as a Mechanism for Slow Slip Events ﻿

(American Geophysical Union, 2010)
The mechanics of slow slip events (SSE) in subduction zones remain unresolved. We suggest that SSE nucleate in areas of unstable friction under drained conditions, but as slip accelerates dilatancy reduces pore pressure ...
• #### Does Shear Heating of Pore Fluid Contribute to Earthquake Nucleation? ﻿

(American Geophysical Union, 2006)
Earthquake nucleation requires reduction of frictional strength $\tau = \mu (\sigma - p)$ with slip or slip rate, where $\mu, \sigma_n$, and $p$ are the friction coefficient, normal stress, and fluid pressure, ...
• #### Dynamic Rupture through a Branched Fault Configuration at Yucca Mountain, and Resulting Ground Motions ﻿

(Seismological Society of America, 2010)
We seek to characterize the likelihood of multiple fault activation along a branched normal-fault system during earthquake rupture using dynamic finite element analyses. This is motivated by the normal faults in the vicinity ...
• #### Earthquake Ruptures with Thermal Weakening and the Operation of Major Faults at Low Overall Stress Levels ﻿

(American Geophysical Union, 2009)
We model ruptures on faults that weaken in response to flash heating of microscopic asperity contacts (within a rate-and-state framework) and thermal pressurization of pore fluid. These are arguably the primary weakening ...
• #### Earthquake Slip Between Dissimilar Poroelastic Materials ﻿

(American Geophysical Union, 2008)
A mismatch of elastic properties across a fault induces normal stress changes during spatially nonuniform in-plane slip. Recently, Rudnicki and Rice showed that similar effects follow from a mismatch of poroelastic properties ...
• #### Effective Normal Stress Alteration due to Pore Pressure Changes Induced by Dynamic Slip Propagation on a Plane Between Dissimilar Materials ﻿

(American Geophysical Union, 2006)
Recent, detailed examinations of fault zones show that walls of faults are often bordered by materials that are different from each other and from the more uniform material farther away. In addition, they show that the ...
• #### Elastic Reciprocity and Symmetry Constraints on the Stress Field Due to a Surface-Parallel Distribution of Dislocations ﻿

(Elsevier, 2011)
Elastic reciprocity and geometric symmetry are used to constrain the expressions for stresses due to introduction of line dislocations near a half-space surface. Specifically, a relationship is shown to exist between the ...
• #### Elastodynamic Analysis for Slow Tectonic Loading with Spontaneous Rupture Episodes on Faults with Rate- and State-dependent Friction ﻿

(American Geophysical Union, 2000)
We present an efficient and rigorous numerical procedure for calculating the elastodynamic response of a fault subjected to slow tectonic loading processes of long duration within which there are episodes of rapid earthquake ...
• #### Exact results with the J-integral applied to free-boundary flows ﻿

(Cambridge University Press, 2002)
We apply the J-integral to free-boundary flows in a channel geometry such as viscous fingering or blob injection in Hele-Shaw cells, void propagation in electromigration, and injection of air bubbles into inviscid liquids. ...
• #### Finite Element Model of Branched Ruptures Including Off-Fault Plasticity ﻿

(Seismological Society of America, 2012)
Fault intersections are a geometric complexity that frequently occurs in nature. Here we focus on earthquake rupture behavior when a continuous, planar main fault has a second fault branching off of it. We use the finite ...
• #### Finite Element Modeling of Branched Ruptures Including Off-Fault Plasticity ﻿

(Seismological Society of America (SSA), 2012)
Fault intersections are a geometric complexity that frequently occurs in nature. Here we focus on earthquake rupture behavior when a continuous planar main fault has a second fault branching off of it. We use the finite ...
• #### Finite Element Simulations of Dynamic Shear Rupture Experiments and Dynamic Path Selection along Kinked and Branched Faults ﻿

(American Geophysical Union, 2009)
We analyze the nucleation and propagation of shear cracks along nonplanar, kinked, and branched fault paths corresponding to the configurations used in recent laboratory fracture studies by Rousseau and Rosakis (2003, ...
• #### Heating and Weakening of Faults During Earthquake Slip ﻿

(American Geophysical Union, 2006)
Field observations of mature crustal faults suggest that slip in individual events occurs primarily within a thin shear zone, <1–5 mm, within a finely granulated, ultracataclastic fault core. Relevant weakening processes ...
• #### Heating, weakening and shear localization in earthquake rupture ﻿

(The Royal Society, 2017-08-21)
Field and borehole observations of active earthquake fault zones show that shear is often localized to principal deforming zones of order 0.1-10 mm width. This paper addresses how frictional heating in rapid slip weakens ...
• #### Ice, Water, Soil and a Barenblatt Ending of a Super-Long Glacial Shear Crack ﻿

(2017-06)
Flow of the Western Antarctic Ice Sheet is distinctly heterogeneous in a vast region bordering the Ross Sea. Broad streaks of ice, ~1 km thick, called "ice streams", having horizontal width of several 10s of km, slide over ...
• #### Influence of Material Contrast on Fault Branching Behavior ﻿

(American Geophysical Union, 2011)
Material contrasts across faults are a common occurrence, and it is important to understand if these material contrasts can influence the path of rupture propagation. Here we examine models, solved numerically, of rupture ...
• #### A Model for Turbulent Hydraulic Fracture and Application to Crack Propogation at Glacier Beds ﻿

(American Geophysical Union, 2010)
Glaciological observations of under‐flooding suggest that fluid‐induced hydraulic fracture of an ice sheet from its bed sometimes occurs quickly, possibly driven by turbulently flowing water in a broad sheet flow. Taking ...
• #### Modeling Slope Instability as Shear Rupture Propagation in a Saturated Porous Medium ﻿

(Springer Verlag, 2009)
When a region of intense shear in a slope is much thinner than other relevant geometric lengths, this shear failure may be approximated as localized slip, as in faulting, with strength determined by frictional properties ...