Puget Sound, Coastal Bluffs, Washington
Data Collection at the two Puget Sound sites is currently suspended
On January 10, 2006, a landslide destroyed most instruments at the Edmonds site. Later, about April 17, a landslide at the Everett site severed cables between the datalogger and instruments on the hillside.
Map of Washington State
Shallow landslides are common on coastal bluffs overlooking Puget Sound. In cooperation with the Washington Department of Transportation, the Burlington Northern Santa Fe Railway, Meteor Communications, and Shannon and Wilson, Inc., we have installed instruments at two sites near Edmonds and Everett, Washington to observe rainfall and subsurface water. Initial installation occurred in September and October 2001. Subsequent changes to instrumentation have addressed failed or malfunctioning instruments and addition of sensors needed to improve the range of observations, such as the addition of tensiometers to document conditions in unsaturated soils. Observation of shallow piezometers ceased in October 2003 as we replaced them with tensiometers. A new type of soil-moisture instrument was also installed at the Edmonds site to replace the water-content reflectometers.
The U.S. Geological Survey has installed instruments in the bluffs near where landslides occurred in 1997 to detect changes in local conditions, including
In many landslides and unstable bluffs, infiltration of rainfall or snowmelt increases ground water pressures. These elevated pressures can, in turn, trigger landslide movement. Measurements are taken at regular intervals and data are transmitted every hour and displayed on graphs that are updated hourly (a few minutes after the hour). Summary graphs are updated daily, shortly after midnight (PST). Updates may be interrupted occasionally by computer or network malfunctions.
Contact Information
Rex Baum
baum@usgs.govU.S. Geological Survey
Geologic Hazards Team
Box 25036, M.S. 966
Denver, CO 80225-
Ed Harp
harp@usgs.govU.S. Geological Survey
Geologic Hazards Team
Box 25036, M.S. 966
Denver, CO 80225
