Certain features unique to the Pacific Northwest influence landsliding in this region. Weakly consolidated sediments, dense vegetation and seasonally concentrated rainfall all contribute to the distinctive conditions that are encountered here. This study gathers together information applying to the recognition and correction of Pacific Northwest landslides. Treatment practices common to this region are discussed. A large slide located about 30 miles east of Portland, Oregon along the Clackamas River is used as an example. Exploration, instrumentation, analysis and corrective measures are illustrated.

No description available.

2v. : / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (D.Sc.)--University of Adelaide, Dept. of Entomology, 1979

Graduation date: 1981 / Best scan available. Figures in original are black and white photocopies.

Graduation date: 1982

The fall-winter surface current field off Oregon was determined by analysis of ten years of drift bottle data. Computer programs were developed for generating bottle tracks on a numerical grid, for interpolating bottle velocity components to fill void grid points and for smoothing irregularities in the velocity fields. Charts are presented showing the spatial distribution of surface currents determined in the study area of 5° latitude by 2-1/2° longitude. The mean currents for the fall-winter season have a predominantly northerly flow with speeds increasing from the south to the north (from 0.01 to 0.35 knots). This probably is a consequence of the increase in speed of southerly winds from south to north in the study area during the fall-winter season. The northly flow in October during the years 1961-70, when compared with the dominant southerly flow during this month from measurements prior to 1935, may indicate a major change of Davidson-California Current System within the past forty years. Apparent onshore flow may be introduced by bottle diffusion; this flow is prominant at all latitudes along which bottle releases are concentrated. An offshore flow component north of 46°30'N may be related to the Columbia River discharge and the westward extension of land. / Graduation date: 1973

Graduation date: 1977

The specific activity of ⁶⁵Zn (nanocuries ⁶⁵Zn/g total Zn) was determined in various organs of the common coastal mussel, Mytilus californianus Conrad, collected from six locations along the Pacific Coast. These organs included the gills, mantle, foot, reproductive organs, adductor muscle, and viscera. After ashing and dissolving with nitric acid (8 M), each tissue was analyzed for ⁶⁵Zn by gamma-ray spectrometry. The determination of total zinc concentrations of the various organs was accomplished by atomic absorption spectrophotometry as well as by neutron activation analysis. Variable amounts of both stable zinc and radioactive ⁶⁵Zn were observed within the specific tissues from a given location. The ⁶⁵Zn specific activities of the tissues of organisms from a particular station however, tended to be uniform, at least within the uncertainty of the measurements. Both radiozinc and ⁶⁵Zn specific activity decreased with distance from the Columbia River mouth, whereas the stable zinc tended to remain uniform for a specific tissue. Tissues high in radiozinc were also high in stable zinc and conversely. An estimate of the input specific activity from the mussel' environment (food and/or water) was calculated from a simple model resulting in a value similar to zooplankton values sampled from within the Columbia River plume. Comparison of the concentrations of zinc determined by neutron activation with those determined by atomic absorption spectrophotometry indicated a linear relationship between the two methods. Results of atomic absorption measurements were approximately 27% larger than the results of neutron activation analysis, indicating the presence of a systematic error. The higher values attained by atomic absorption are attributed to evaporation during storage of the ash solution which would lead to an increase in zinc concentration. In considering the two methods of analysis, economy of both time and expenses favors the atomic absorption method over that of neutron activation. / Graduation date: 1971

A structure map was constructed of the continental shelf between Cape Blanco and Coos Bay, Oregon, exclusively from an interpretation of approximately 700 km of continuous seismic profiles. At least ten discernible seismic units were mapped on the bases of acoustic appearance, lateral continuity, angular unconformities, and faults. The offshore units tentatively were correlated with onshore geology and are believed to range in age from the latest Jurassic to late Pleistocene. The sparker profiles reveal that the continental shelf off southern Oregon has experienced significant late Tertiary and Quaternary accretion due to deposition and tectonic uplift. The oldest rock exposures, believed to be the latest Jurassic in age, crop out on the inner continental shelf on the topographic highs off Cape Blanco and Coquille Point. Erosional remnants of probable Late Cretaceous turbidites and the middle Eocene sandstone beds also are exposed on the bathymetric high on the inner shelf southwest of Cape Arago. The initial emplacement of these three uplifted structural blocks is probably a result of late Eocene wrench faulting of the Port Orford shear zone and of the postulated shear zone at Coquille Point. No other early Tertiary sediments apparently are exposed on this portion of the Oregon continental shelf, but they probably extend seaward at depth on the continental margin. Middle Tertiary strata are believed to be exposed on the outer shelf topographic high southwest of Cape Arago. Sediments of Miocene to Pliocene age were deposited throughout much of the continental shelf that was surveyed. The greatest amount of deposition occurred in a north-south trending basin between Cape Blanco and Coquille Bank. Late to post-Pliocene tectonism uplifted and exposed the older underlying rocks on the inner shelf, which are probably of uppermost Jurassic to middle Tertiary age. These same stresses also deformed the Mio-Pliocene sediments into gently undulating structures on the inner shelf. The greatest deformation occurred on the outer shelf and formed Coquille Bank, a north-south trending, doubly plunging, asymmetrical anticline. The terraces or benches on the upper continental slope to the north and south of the Bank are structural features resulting from the doubly plunging anticline. Eustatic sea level lowerings during the Pleistocene truncated the shelf structures as deep as 130 m below present sea level. The detritus was deposited as a wedge of sediments, which forms an unconformable contact with the underlying strata on the outer shelf and upper slope between Coos Bay and Coquille Bank. In areas of deposition there is no distinct break between the shelf and the upper slope; the former merely merges into the latter in a continuous convex curve. In areas of nondeposition, the edge of the shelf is an erosional and structural feature. A possible buried channel was detected northwest of the mouth of the Coquille River. This sediment filled channel is believed to be an erosional remnant of a former course of the Coquille River during a lower stand of sea level. / Graduation date: 1969

A radiation model was developed for retrieving cloud visible optical depth, droplet effective radius, and cloud top emission temperature using AVHRR satellite observations at 0.63, 3.7, and 11 ��m. The model was used to determine the sensitivity of the retrieved properties to various approximations often employed in such retrievals. Droplet effective radius appears to be the most sensitive to the commonly used approximations. Cloud properties retrieved using a 16-stream scheme were within ��5% of those retrieved using a 148-stream scheme. Cloud properties retrieved using double Henyey-Greenstein phase functions were within ��10% of those retrieved using Mie scattering. The retrieved cloud properties were used to investigate biases that arise when partly cloudy pixels were assumed to be overcast and biases that arise due to oblique satellite view angles. On average, cloud visible optical depths retrieved for partly cloudy pixels were 40-60% of those retrieved for overcast pixels. Likewise, cloud liquid water paths were 30-50%, droplet effective radii were 1-3 ��m smaller, and cloud top emission temperatures were 2-4K larger. Cloud visible optical depths retrieved at 60�� satellite zenith angles were 60-70% of those retrieved at nadir. The retrieved droplet effective radii and cloud top emission temperatures varied little with changing satellite zenith angle. For March 1989, cloud optical depths and cloud emission temperatures retrieved for pixels overcast by single-layer, low-level clouds were negatively correlated. Cloud optical depth, liquid water path, and droplet effective radius were positively correlated with the sea surface-cloud top temperature difference. The retrieved cloud properties were also compared for the spatial coherence, CLAVR (Clouds from AVHRR), and a threshold method based on International Satellite Cloud Climatology Project procedures. For regions containing single-layered cloud systems, fractional cloud cover and cloud brightness temperatures derived by the ISCCP-like threshold method were systematically larger than those derived by the spatial coherence method, whereas cloud reflectivities were systematically smaller. Cloud reflectivities and brightness temperatures derived by CLAVR and the spatial coherence method were in better agreement. / Graduation date: 1998