Elliptical borehole enlargements or "breakouts" caused by systematic spalling of a
borehole wall due to regional maximum horizontal stresses were identified in 18 wells
drilled in the Coast Range and Willamette Valley of western Oregon. The breakouts
generally indicate a NNW to NNE orientation of maximum horizontal compression
(oH[subscript max])...
Two examples of Pacific rim plate boundary deformation are presented. In the first
part of the thesis crustal models are derived for the northwestern part of the Vizcaino
block in California using marine seismic and gravity data collected by the Mendocino
Triple Junction Seismic Experiment. A northwest-southeast trending kink in...
This thesis presents elastic finite difference simulations of two dimensional wavefield propagation for line-9, recorded during the 1993 part of the multi-institutional, multi-year Mendocino Triple Junction (MTJ) Seismic Experiment. Line-9 is a high-resolution, large-aperture seismic profile oriented in north-south direction, extending from the subduction regime north of the MTJ to...
Anomaly timescales for the last 90 million years, derived from
marine magnetic profiles and published prior to mid-1979, are summarized,
illustrated for comparison, and critically reviewed. A revised timescale
is constructed using calibration points which fix the ages of anomalies
2.3', 5.5, 24, and 29. An equation is presented for...
During the Cenozoic, tectonics in the Cuyama basin of the southeastern Salinian block changed from extension to strike-slip faulting to compression and rotation. During the Oligocene-early Miocene, the Cuyama basin was adjacent to the southern Mojave region and part of that extensional tectonic regime. Many present-day reverse faults have an...
Plate boundaries are commonly regions of complex, diffuse deformation with
the motion across the boundary accommodated by numerous structural systems, rather
than being narrow, discrete zones of deformation. One such boundary occurs where
the North American plate makes contact with Juan de Fuca, Gorda, and Pacific plates
along the west...