[1] We use ground geodetic and interferometric synthetic aperture radar satellite observations across the southern San Andreas (SAF)-San Jacinto (SJF) fault systems to constrain their slip rates and the viscosity structure of the lower crust and upper mantle on the basis of periodic earthquake cycle, Maxwell viscoelastic, finite element models. Key questions for this system are the SAF and SJF ...

[1] 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 in large crustal events are therefore suggested to be thermal, and to involve the following: (1) thermal pressurization of pore fluid within and adjacent to the deforming f...

S U M M A R Y We develop a frequency-based approach to earthquake slip inversion that requires no prior information on the rupture velocity or slip-rate functions. Because the inversion is linear and is performed separately at each frequency, it is computationally efficient and suited to imaging the finest resolvable spatial details of rupture. We demonstrate the approach on synthetic seismogra...

Slow-slip events, or ‘silent earthquakes’, have recently been discovered in a number of subduction zones including the Nankai trough in Japan, Cascadia, and Guerrero in Mexico, but the depths of these events have been difficult to determine from surface deformation measurements. Although it is assumed that these silent earthquakes are located along the plate megathrust, this has not been proved...

[1] The 1999 Chi-Chi earthquake, Mw = 7.6, broke a major thrust fault along the western foothills of the Central Range of Taiwan. We have measured the horizontal coseismic displacement field by correlating optical satellite images acquired before and after the earthquake. These data reveal the fault trace and a clockwise rotation of surface displacements toward the north with much larger displa...

The 27 February 2010 Mw 8.8 Maule, Chile, earthquake ruptured over 500 km along a mature seismic gap between 341 S and 381 S—the Concepción–Constitución gap, where no large megathrust earthquakes had occurred since the 1835Mw 8.5 event. Notable discrepancies exist in slip distribution and moment magnitude estimated by various models inverted using traditional observations such as teleseismic ne...

Kuhbanan fault system, as one of the intracontinental faults of central Iran, is recognized by considerable seismogenic activities and modern morphotectonics evidences with a strike-slip (reverse component) motion. According to the geometric and kinematics data, Kuhbanan fault has been divided into 5 segments (S26, S27, S28, S29, S30) in Bahabad region. Measured geomorphic indices of ratio of v...

We discuss 2D simulations of in-plane ruptures on a fault between different solids in a model that includes dynamic generation of plastic strain off the fault. The fault is governed by a regularized friction with a gradual response to abrupt changes of normal stress, while plastic strain in the bulk is governed by a Coulomb yielding criterion. The occurrence of off-fault damage stabilizes the s...

Empirically based rate-and-state friction laws (RSFLs) have been proposed to model the dependence of friction forces with slip and time. The relevance of the RSFL for earthquake mechanics is that few constitutive parameters define critical conditions for fault stability (i.e., critical stiffness and frictional fault behavior). However, the RSFLs were determined from experiments conducted at sub...

[1] We find that slow seismic events have smaller fault slips compared to ordinary earthquakes with similar dimensions. For ordinary earthquakes, the ratio of slip to fault length is largely consistent, yet the physical controls on this ratio are unknown. Recently discovered slow slip or creep events in which faults move quasi-statically over periods of days to years shed new light on this old ...