Nine west-northwest-trending faults on the continental margin of
Oregon and Washington, between 43° 05'N and 470 20'N latitude, have been
mapped using seismic reflection, sidescan sonar, submersibles, and swath
bathymetry. Five of these oblique faults are found on both the Juan de Fuca
and North American plates, and offset abyssal...
Seismically active areas exist within Oregon. The seismic history of Oregon is too short to be used as an accurate predictor of earthquake size, number, and distribution. Continual monitoring of earthquakes by seismograph stations during the next several decades should provide a more accurate estimate of the seismicity of Oregon....
Landslides are ubiquitous within the state of Oregon, imposing an annual estimated cost of more than $10 million. Weak, saturated soils at steep slopes combined with persistent rainfall throughout most of the year provide a dangerous environment for this natural disaster, particularly in western Oregon. This grim situation is intensified...