Two monuments from an 1855 cadastral survey that span the San Andreas fault in the Carrizo Plain have been right-laterally displaced 11.0 --2.5 m by the 1857 Fort Tejon earthquake and associated seismicity and afterslip. This measurement confirms that at least 9.5 --0.5 m of slip occurred along the main fault trace, as suggested by measurements of offset channels near Wallace Creek. The slip va...

We use L-band Advanced Land Observation Satellite PALSAR data to infer the distribution of subsurface fault slip during the Tarlay earthquake (Mw 6.8) in eastern Myanmar. We find the total length of surface rupture is approximately 30 km, with nearly 2 m maximum surface offset along the westernmost section of the Nam Ma fault (the Tarlay segment). Finite-fault inversions constrained by Interfer...

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...

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...

A simple mechanical model and dimensional analysis are used to derive a scaling law for the partitioning between slip rate on a strike-slip fault and distributed deformation in the far-field. The depth of the fault, the distributions of stress, strain rate and slip rate are solved for a given far-field force or displacement in a 2-D medium with a linear temperature-dependent viscous rheology. A...

Near-field co-seismic GPS data were used to derive the slip distribution of the 12 May 2008 Wenchuan earthquake. Based on field measurements and geological observations, the earthquake is represented by ruptures on the Beichuan fault and a neighboring fault from Pengxian to Guanxian, both dipping with a decreasing angle with depth. Using a layered elastic crust model, we obtained a slip model t...

Seismic reflection profiles, drill-hole data, and geologic maps delimit the form of normal faults and Tertiary sedimentary rocks in the southern half of the Cache Valley basin in northern Utah. Dips of faults and sedimentary rocks were estimated from time-migrated reflection profiles by using the stacking velocities for the data. At the southern end of the basin, the East Cache fault zone is li...

[1] The 1994 Double Spring Flat (DSF) earthquake (M5.9) was the largest earthquake to strike Nevada in more than 30 years. It occurred in the Sierra Nevada-Basin and Range Transition Zone within a step-over region between two major normal faults. Descending and ascending ERS interferograms show a maximum range change of 8.5 cm which is the coseismic ground displacement associated with this norm...

Triaxial experiments show that samples of fault gouge deform distinctly differently than those from the adjacent fault damage zone (e.g., Chester and Logan, 1986). Rock samples in the damage zone follow a characteristic elastic-brittle behavior, whereas fault gouge readily compacts and deforms in a more ductile manner. In order to explain the apparent weakness of large plate bounding faults suc...

We investigate whether a shallow-dipping thrust fault is prone to waveslip interactions via surface-reflected waves affecting the dynamic slip. If so, can these interactions create faults that are opaque to radiated energy? Furthermore, in this case of a shallow-dipping thrust fault, can incorrectly assuming a transparent fault while using dislocation theory lead to underestimates of seismic mo...