[1] We used dense linear seismic arrays across and along the San Andreas Fault (SAF) at Parkfield, California to record fault zone trapped waves generated by explosions and microearthquakes in 2002. Prominent trapped waves appeared at stations close to the SAF main fault trace while some energy was trapped in the north strand at the array site. Observations and 3-D finitedifference simulations ...

Damage to fault-zone rocks during fault slip results in the formation of a channel of low seismic-wave velocities. Within such channels guided seismic waves, denoted by Fg, can propagate. Here we show with core samples, well logs and Fg-waves that such a channel is crossed by the SAFOD (San Andreas Fault Observatory at Depth) borehole at a depth of 2.7 km near Parkfield, California, USA. This l...

Physical limits on ground-motion parameters can be estimated from spontaneous-rupture earthquake models but are subject to uncertainties in model parameters. We investigate physical limits at Yucca Mountain, Nevada, and assess sensitivities due to uncertainties in fault geometry, off-fault rock strength, the seismogenic depth, fault zone structure, and undrained poroelastic response of the flui...

[1] We examine how frictional heating drives the evolution of temperature, strength, and fracture energy during earthquake slip. For small slip distances, heat and pore fluid are unable to escape the shearing fault core, and the behavior is well approximated by simple analytical models that neglect any transport. Following large slip distances, the finite width of the shear zone is small compar...

Assessment of the reservoir structure and determination of theinsitu stress direction arenecessary in oil production optimization andfield development. Today, the application of reservoir software and Image logsplay a central role in resolving this problem. Electricand ultrasonic imaging tools record vast amounts of high-resolution data within the borehole wall. This enables the geoscientists t...

the presence of radon in drinking water causes health risks associated with exposure from both inhalation and ingestion. since the studies show that faults near the water resources have a critical effect on the concentration of radon, kouhbanan active fault zone, to find water resources  with high radon concentration was chosen for the following investigation. water samples were taken from all ...

Unique attributes in sequences of recurring, similar microearthquakes at Parkfield, California, provide a means for inferring slip rate at depth throughout the active fault surface from the time intervals between sequence events. Application of the method using an 11-year microseismicity record revealed systematic spatial and temporal changes in the slip rate that were synchronous with earthqua...

[1] The magnetotelluric dataset collected on the San Andreas Fault at Parkfield has been re-analyzed using superior inversion algorithms that have been developed in recent years. A combination of constrained inversion, forward modeling and synthetic inversion studies are used, and show that at the SAFOD site, the low resistivity fault zone extends to a depth of 2–3 km. An extended zone of low r...

[1] We studied the complex multiple-faulting pattern of the 40-km-long rupture zone of the 1999 M7.1 Hector Mine, California, earthquake with fault zone trapped waves generated by near-surface explosions and aftershocks, and recorded by linear seismic arrays deployed across the surface rupture. The explosion excited trapped waves, with relatively large amplitudes at 3–5 Hz and a long duration o...

[1] We studied the anatomy of the fault system where the 2009L’Aquila earthquake (MW 6.1) nucleated by means of ~64 k high-precision earthquake locations spanning 1 year. Data were analyzed by combining an automatic picking procedure for P and S waves, together with cross-correlation and double-difference location methods reaching a completeness magnitude for the catalogue equal to 0.7 includin...