We present an efficient and rigorous numerical procedure for calculating the elastodynamic response of a fault subjected to slow tectonic loading processes long duration within which there are episodes rapid earthquake failure. This is done general class rate‐ state‐dependent friction laws with positive direct velocity effect. The algorithm allows us treat accurately, single computational procedure, intervals thousands years calculate, each episode, initially aseismic accelerating slip prior...

Crustal deformation patterns are affected by multiscale granulation and healing processes associated with phase transitions between continuum discrete states of rocks. The ongoing continuum‐discrete accompanied progressive evolution disordered fault networks to dominant localized zones, development bimaterial interfaces, increasing dynamic weakening surfaces. Results on individual zones point three general regimes. first is broad range heterogeneities, little weakening, power law...

Pulses of slip velocity can propagate on a planar interface governed by constant coefficient friction, where the separates different elastic materials. Such pulses have been found in two‐dimensional plane strain finite difference calculations fault between media with wave speeds differing 20%. The self‐sustaining propagation pulse arises from interaction normal and tangential deformation that exists only material contrast. These confirm prediction Weertman [1980] dislocation propagating...

Abstract We use recent results on statistical analysis of seismicity to present a robust method for comprehensive detection and earthquake clusters. The is based nearest‐neighbor distances events in space‐time‐energy domain. applied 1981–2011 relocated catalog southern California having 111,981 with magnitudes m ≥ 2 corresponding synthetic catalogs produced by the Epidemic Type Aftershock Sequence (ETAS) model. Analysis ETAS model demonstrates that cluster are accurate stable respect (1)...

A basic micromechanical model for deformation of solids with only one tuning parameter (weakening $\ensuremath{\epsilon}$) is introduced. The can reproduce observed stress-strain curves, acoustic emissions and related power spectra, event statistics, geometrical properties slip, a continuous phase transition from brittle to ductile behavior. Exact universal predictions are extracted using mean field theory renormalization group tools. results agree recent experimental observations...

We present a formulation for mechanical modeling of geological processes in the seismogenic crust using damage rheology. The layer is treated as an elastic medium where distributed damage, modifying stiffness, evolves function deformation history. model rheology based on thermodynamic principles and fundamental observations rock deformation. theoretical analysis leads to kinetic equation evolution having two principal coefficients. first criterion transition between strength degradation...

We study in-plane ruptures on a bimaterial fault governed by velocity-weakening friction with regularized normal stress response. Numerical simulations and analytical estimates provide characterization of the ranges scales, nucleation lengths background stresses for which behave as cracks or pulses, decaying sustained, bilateral unilateral. With strongly friction, occur under wide range conditions large-scale pulses preferred propagation direction, that slip more compliant material. Such...

Numerical simulations of earthquake failure sequences along a discrete cellular fault zone are performed for three‐dimensional (3‐D) model representing approximately the central San Andreas fault. The consists an upper crust overlying lower and mantle region, together defining elastic half‐space with vertical half‐plane contains region where slip is calculated on uniform grid cells governed by static/kinetic friction law regions prescribed so as to represent tectonic loading, aseismic creep,...

Simple models for ruptures along a heterogeneous earthquake fault zone are studied, focusing on the interplay between roles of disorder and dynamical effects. A class found to operate naturally at critical point whose properties yield power-law scaling statistics. Various effects can change behavior distribution small events combined with characteristic system size events. The studies employ various analytic methods as well simulations.

We report on numerical simulations of slip evolution along a two dimensional (slip varies only with depth) vertical strike‐slip fault in an elastic half‐space, using framework incorporating full inertial elastodynamics. The model is follow‐up earlier quasi‐static and quasi‐dynamic deformations smooth systems continua. driven below crustal depth 24 km by constant plate velocity 35‐mm/yr. Deformation at each location the zone sum rate contributions from rate‐ state‐dependent friction power law...

We summarize studies of earthquake fault models that give rise to slip complexities like those in natural earthquakes. For smooth faults between elastically deformable continua, it is critical the friction laws involve a characteristic distance for weakening or evolution surface state. That results finite nucleation size, coherent patch h*. Models faults, using numerical cell size properly small compared h*, show periodic response complex and apparently chaotic histories large events but...

We discuss the subsurface structure of Karadere–Duzce branch North Anatolian Fault based on analysis a large seismic data set recorded by local PASSCAL network in 6 months following Mw= 7.4 1999 Izmit earthquake. Seismograms observed at stations located immediate vicinity rupture zone show motion amplification and long-period oscillations both P- S-wave trains that do not exist nearby off-fault stations. Examination thousands waveforms reveals these characteristics are commonly generated...

Numerical simulations of slip instabilities on a vertical strike‐slip fault in an elastic half‐space are performed for various models belonging to two different categories. The first category consists inherently discrete cellular models. Such used represent systems made segments (modeled by numerical cells) that can fail independently one another. Their quasi‐independence is assumed provide approximate representation strong heterogeneity, due geometric or material property disorder, arrest...

We perform 2-D finite-difference calculations of mode II rupture along a bimaterial interface governed by slip-weakening friction, with the goal clarifying properties and conditions leading to development unilateral wrinkle-like pulses. The simulations begin an imposed bilateral in limited source region. Rupture outside are examined for ranges values degree material contrast γ across fault, difference between static fs dynamic fd coefficients friction initial shear stress. results show that...

We perform analytical and numerical studies of aftershock sequences following abrupt steps strain in a rheologically layered model the lithosphere. The consists weak sedimentary layer, over seismogenic zone governed by viscoelastic damage rheology, underlain upper mantle. rheology accounts for fundamental irreversible aspects brittle rock deformation is constrained laboratory data fracture friction experiments. A 1-D version leads to an exponential solution rates. corresponding 3-D volume...

Abstract We decompose a general seismic potency tensor into isotropic tensor, double-couple and compensated linear vector dipole using the eigenvectors eigenvalues of full tensor. Two dimensionless parameters are used to quantify size components. The have well-defined finite ranges suited for non-linear inversions source tensors from waveform data. decomposition parametrization obtain corresponding results moment relations between different in media derived. also discuss appropriate...