Knife Ridge, Elliott State Forest, Oregon

Science Center Objects

Recent Conditions

The instruments for this site were installed in the summer and fall of 2009 and are used to monitor and detect changes in local conditions, including:

Measurements are taken at 15-minute intervals and data are transmitted hourly and displayed on graphs that are updated hourly.

Project Background

Landslides in the Oregon Coast Range impact people and the environment and are commonly induced by intense or prolonged rainfall associated with strong storms in the late fall and winter seasons. For example, in February and November of 1996 heavy rainfall from two unusually large storms induced thousands of landslides over a large part of western Oregon.

The USGS and its cooperators have installed instruments in a steep hillside about 20 km southeast of Reedsport in the Elliott State Forest. Data collection at this site supports research on hydrologic factors that control landslide initiation. In many landslide-prone hillsides, infiltration of water from rainfall or snowmelt increases ground-water pressures. These elevated pressures can, in turn, induce landslide movement.

Contour map of the stations set up on the hillside at Knife Ridge

Topographic map of Knife Ridge showing soil pit locations and survey points. (Public domain.)

Image of the hillside and where each station is set up there at Knife Ridge

Oblique photograph of Knife Ridge monitoring site showing approximate soil pit locations. (Public domain.)


Employees digging into the ground to set up monitoring stations on the hillside of Knife Ridge

Team geologists using a slide hammer to prepare for tensiometer installation. (Public domain.)

Employees setting up monitoring devices on the hillside of Knife Ridge

Typical tensiometer installation near (backfilled) exploration pit. (Public domain.)


Scientists installing equipment at monitoring site in the Oregon Coast Range, white box in upper left quadrant of photograph con

Scientists installing equipment at a monitoring site in the Oregon Coast Range, white box in the upper left quadrant of the photograph contains data collection and transmission equipment (Photo by R.L.Baum, U.S. Geological Survey, July 2009, Public domain.)