This paper is concerned with some aspects of nonuniform stressing above a deep creeping portion of a fault zone prior to a large crust-breaking earthquake. The model that we use involves a slipping crack, representing the deeper, more stably sliding portions of the fault zone, which penetrates upward from depth and is blocked in the lower region of the seismogenic zone. When conditions are unif...

We have determined a source rupture model for the 1992 Landers earthquake (Mw 7.2) compatible with multiple data sets, spanning a frequency range from zero to 0.5 Hz. Geodetic survey displacements, near-field and regional strong motions, broadband teleseismic waveforms, and surface offset measurements have been used explicitly to constrain both the spatial and temporal slip variations along the...

[1] We report on laboratory experiments which investigate interactions between aseismic slip, stress changes, and seismicity on a critically stressed fault during the nucleation of stick-slip instability. We monitor quasi-static and dynamic changes in local shear stress and fault slip with arrays of gages deployed along a simulated strike-slip fault (2m long and 0.4m deep) in a saw cut sample o...

Metamorphic and various intrusive rocks in the Urmia area are located in a transpressed active continental margin. These complexes in the Zagros orogen were deformed during an oblique convergence scenario between the Arabian and Sanandaj–Sirjan blocks in NW Iran. The Urmia area contains both NW-SE striking dextral strike-slip and SW verging NE dipping ductile reverse shear fabrics. Ductile shea...

We have determined a source rupture model for the 1992 Landers earthquake (Mw 7.2) compatible with multiple data sets, spanning a frequency range from zero to 0.5 Hz. Geodetic survey displacements, near-field and regional strong motions, broadband teleseismic waveforms, and surface offset measurements have been used explicitly to constrain both the spatial and temporal slip variations along the...

Recent observations suggesting the influence of creep on earthquakes nucleation and arrest are strong incentives to investigate the physical mechanisms controlling how active faults slip. We focus here on deriving generic characteristics of shallow creep along the Haiyuan fault, a major strike-slip fault in China, by investigating the relationship between fault slip and geometry. We use optical...

Two-dimensional, numerical models of a linear fault embedded within a linear elastic medium show the generation of off-fault tensile failure that results from inelastic slip along the fault. We explore quasistatic models with slip-weakening friction to assess the effects of spatially and temporally variable friction on the damage patterns. Tensile fractures form where tangential normal stresses...

[1] We perform two-dimensional dynamic models of strike-slip faults with a change in strike (a bend) over multiple earthquake cycles to examine the long-term effects of nonplanar fault geometry. A viscoelastic model (a proxy for off-fault deformation and tectonic loading) is introduced for the interseismic process to avoid pathological stress buildup around the bend. A finite element method wit...

[1] We develop a two-dimensional boundary element earthquake cycle model including deep interseismic creep on vertical strike-slip faults in an elastic lithosphere coupled to a viscoelastic asthenosphere. Uniform slip on the upper part of the fault is prescribed periodically to represent great strike-slip earthquakes. Below the coseismic rupture the fault creeps in response to lithospheric shea...