Carmel Knoll Landslide, Lincoln County, Oregon
Deep, primarily translational landslides in sedimentary bedrock are common along the central coast of Oregon and generally move several centimeters during winter rainy seasons. These landslides pose significant hazards to people, U.S. Highway 101, other infrastructure, and the economic health of the region. For example, landslide movement has resulted in some coastal communities being nearly isolated for months, which has caused economic hardship as tourism is a primary industry along the coast. During the 1940s, the Jump-Off-Joe landslide located within the city of Newport destroyed 15 homes.
The U.S. Geological Survey (USGS), with the cooperation and assistance of the Oregon Department of Transportation (ODOT), the Oregon Parks and Recreation Department, and the Oregon Department of Geology and Mineral Industries, is monitoring three landslides located about 6-11 km north of Newport in an effort to better understand conditions resulting in their movement. Much of the monitoring equipment at the Carmel Knoll landslide was installed by ODOT during the 1990s. The remainder of the equipment was installed by the USGS during January 2008. Equipment was installed to monitor landslide movement, rainfall, and groundwater pressures. Infiltration of rainfall generally elevates groundwater pressures, which reduces frictional strength along the base of landslides and may result in their movement.
Monitoring equipment is sampled every 15 minutes and results are transmitted daily from the landslides to the USGS office in Golden, Colorado via cellular modems. The data plots on linked web pages are also updated daily. However, cellular signal strength is marginal at the landslides so days during which data transmissions fail are common. In addition, other problems with data transmission, monitoring equipment, office computers, and networks may result in late updates or a complete lack of monitoring results.
- Johnson Creek Landslide
- Devil's Punchbowl Landslide
- (2012) Schulz, William H., Galloway, Sarah L., and Higgins, Jerry D., 2012, Evidence for earthquake triggering of large landslides in coastal Oregon, USA: Geomorphology, vol. 141-142, p. 89-98. doi:10.1016/j.geomorph.2011.12.026
- Priest, G.R., Schulz, W.H., Ellis, W.L., Allan, J.A., Niem, A.R., and Niem, W.A., 2011, Landslide stability: role of rainfall-induced, laterally propagating, pore-pressure waves: Environmental & Engineering Geoscience, v. XVII, no. 4, p. 315-335.
wschulz [at] usgs [dot] gov
U.S. Geological Survey
Central Region Geologic Hazards Team
Box 25046, DFC
Mail Stop 966
Denver CO 80225