Abstract There is a sparse number of credible source models available from largemagnitude past earthquakes. A stochastic source-model-generation algorithm thus becomes necessary for robust risk quantification using scenario earthquakes. We present an algorithm that combines the physics of fault ruptures as imaged in laboratory earthquakes with stress estimates on the fault constrained by field ...

The near-source energy released on a fault is estimated through the strain energy change and the fracture energy from the results of kinematic waveform inversion and dynamic modeling for two different types of earthquakes: a shallow crustal earthquake, the 2000 Tottori, Japan (Mw 6.6) earthquake, and an in-slab event, the 1999 Oaxaca, Mexico (Mw 7.5) earthquake. The procedure incorporates the s...

Earthquakes can cause tremendous loss of life and property yet predicting the behavior of earthquake fault systems is exceptionally difficult. The Earths crust is complex and earthquakes generate at depth, which is problematic for understanding earthquake fault behavior. Geodetic imaging observations of crustal deformation from Global Positioning System (GPS) and Interferometric Synthetic Apert...

[1] The clustering of earthquakes in time on the same fault affects the rate and pattern of interseismic deformation. We develop a simple analytic viscoelastic model of the surface velocity field through a clustered earthquake cycle by superposing the velocities of individual earthquake cycles of constant period but varying phase. Velocity profiles prior to and after an earthquake show a wider ...

On 24 August 2014, the M 6.0 South Napa earthquake shook much of the San Francisco Bay area, leading to significant damage in the NapaValley. The earthquake occurred in the vicinity of the West Napa fault (122.313° W, 38.22° N, 11.3 km), a mapped structure located between the Rodger’s Creek and Green Valley faults, with nearly pure right-lateral strike-slip motion (strike 157°, dip 77°, rake –1...

As preparation for this Dahlem Workshop on The Dynamics of Fault Zones, specifically on the subtopic “Rheology of Fault Rocks and Their Surroundings,” we addressed critical research issues for understanding the seismic response of fault zones in terms of the constitutive response of fault materials. This requires new concepts and a host of new observations and experiments to document material r...

Faults in complex tectonic environments interact in various ways, including triggered rupture of one fault by another, that may increase seismic hazard in the surrounding region. We model static and dynamic fault interactions between the strike-slip and thrust fault systems in southern California. We find that rupture of the Sierra Madre-Cucamonga thrust fault system is unlikely to trigger rupt...

In this study, joint inversions of Synthetic Aperture Radar (SAR) and Global Position System (GPS) measurements are used to investigate the source parameters of four Mw > 5 events of the 2016–2017 Central Italy earthquake sequence. The results show that the four events are all associated with a normal fault striking northwest–southeast and dipping southwest. The observations, in all cases, are ...

The Wells 6.0 magnitude earthquake of February 21, 2008, occurred on a previously unrecognized northeast-striking southeast-dipping fault situated beneath Town Creek Flat, a few miles north of Wells, Nevada. Focal depth of the earthquake was 5 miles (8 km). Bedrock geology in the surrounding ranges did not indicate the existence of the fault prior to the earthquake, and no surface rupture has b...

[1] Spatially averaged, absolute deviatoric stress tensors along the faults ruptured during the 2002 Denali fault earthquake, both before and after the event, are derived, using a new method, from estimates of the orientations of the principal stresses and the stress change associated with the earthquake. Stresses are estimated in three regions along the Denali fault, one of which also includes...