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No description available.

Timber management of coastal watersheds in southwest Oregon has been complicated by the need to protect anadromous fish habitat from accelerated stream sedimentation resulting from management activity. The rugged terrain of the Elk and Sixes River basins is underlain by the complex geological province of the Klamath Mountains, in which landslides are a common, natural, and important process of sediment production. A landslide investigation, using sequential aerial photographs which covered a time period of 37 years, was used to determine relationships between mass-wasting, geologic types, and timber harvest practices. Averaged over all rock types, harvested areas showed an increase in failure rate of 7 times, and roaded areas an increase of 48 times that of forested terrain. Terrane underlain by dioritic intrusions was the most sensitive to road-related activity, with an increase in failure rate of up to 108 times that of comparable unmanaged land. The complexity of lithologies and deformational history in the area strongly influence slope morphology, and produces characteristic soil types which experience predictable modes and rates of slope failure. Debris slides and torrents are the dominant form of mass-wasting in dioritic and Cretaceous sedimentary terrane. Areas underlain by more clay-rich metamorphic bedrock are prone to slumps and planar streambank failures. Stream morphology is profoundly influenced by both rock type and geologic structure. Within an area characterized by steep, deeply incised streams, several persistent low-gradient reaches were delineated. These low-gradient stream reaches occur where (1) large landslides have locally raised channel bed elevation and (2) valley-floor widening has occurred in sheared rocks along fault zones or in more readily eroded rock types upstream of rock types resistant to fluvial erosion. / Graduation date: 1987

Tsunamis are gravity water waves that are generated by impulsive disturbances such as submarine earthquakes, landslides, volcanic eruptions, underwater explosions or asteroid impacts. Submarine earthquakes are the primary tsunami source, but landslides may generate tsunamis exceeding tectonic tsunamis locally, in both wave and runup heights. The field data on landslide tsunami events are limited, in particular regarding submarine landslide dynamics and wave generation. Tsunamis generated by three-dimensional deformable granular landslides are physically modeled in the NEES (Network of Earthquake Engineering Simulation) 3D tsunami wave basin (TWB) at Oregon State University in Corvallis, Oregon. A novel pneumatic landslide tsunami generator is deployed to simulate natural landslide motion on a hill slope. The instrumentation consists of various underwater, above water and particle image velocimetry (PIV) cameras, numerous wave and runup gauges and a multi-transducer acoustic array (MTA). The subaerial landslide shape and kinematics on the hill slope and the surface elevation of the offshore propagating tsunami wave and runup on the hill slope are measured. The evolution of the landslide front velocity, maximum landslide thickness and width are obtained along the hill slope. The landslide surface velocity distribution is obtained from the PIV analysis of the subaerial landslide motion. The shape and the size of the submarine landslide deposit are measured with the MTA. Predictive equations are obtained for the tsunami wave amplitude, wave period and wavelength in terms of the non-dimensional landslide parameters. The generated 3D tsunami waves propagate away from the landslide source as radial wave fronts. The amplitudes of the leading tsunami waves decay away from the landslide source in radial and angular direction. The wave celerity of the leading tsunami wave may be approximated by the solitary wave speed while the trailing waves are slower due to the dispersion effects. The energy conversion rate between the landslide and the generated wave is estimated. The observed waves are weakly non-linear in nature and span from shallow water to deep water depth regime. The unique experimental data serves the validation and advancement of numerical models of tsunamis generated by landslides. The obtained predictive equations facilitate initial rapid tsunami hazard assessment and mitigation.

Thesis (M.S.)--Oregon State University, 2004. / Typescript (photocopy). Includes bibliographical references (leaves 58-61). Also available via the World Wide Web.

Thesis (M. Phil.)--University of Hong Kong, 1994. / Includes bibliographical references (leaves 117-126).

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No description available.

No description available.

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.