The middle to upper Eocene Tillamook Volcanics form the basement in the Rock Creek - Rocky Point area. These tholeiitic to alkalic basalts, basaltic andesites, and andesites were erupted as shield volcanoes seaward of the strandline ontop of an older deep-marine mudstone unit (Yamhill Formation) and an accreted portion of...
Sand dunes provide coastal communities critical protection from flooding and erosion, as well as a habitat for a range of species- some threatened or endangered. As such, it is of importance to develop a quantitative understanding of the processes through which these systems evolve at a variety of temporal and...
Mt. Hood, in north-central Oregon, has experienced 13 M ≥ 3.0 earthquakes since 1980. 1812 earthquakes that range in magnitude from -1.1 to 4.5 have been recorded in the region during the same time frame. This paper analyzes four of the larger earthquakes to provide moment tensor solutions and relocated...
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])...
The movement characteristics of five landslides are
compared and interpreted based on records of approximately
10-years duration. Condon landslide in the Oregon Coast
Range has consistently exhibited brief (1 - 8 days) movement
episodes in wet winter months, separated by long periods of
no movement. The translatory movement is probably...
This thesis presents a hydrogeologic study of the Parrett Mountain Region,
located approximately 20 miles south of Portland, Oregon. The aim of the study was
to investigate the impacts of Columbia River Basalt on the regional groundwater
system, to expand our understanding of flow through fractured basalt, to improve
management...
This study assessed how logging-access roads may have contributed to
observed historical increases in peak discharges associated with small and large
logged basins in the western Cascades of Oregon. The study was conducted on
the Lookout Creek (62km²) and the upper Blue River (118km²) basins. Potential
road effects on hydrology...
This research sought to explore the implications of different tenure regimes for both
landscape-level ecological processes and the overall resilience of a social-ecological
system in Central Oregon. The purchase by an investor of former industrial timberlands
known as the Bull Springs tract raised the specter of dispersed residential development on...
