Portland, Oregon

Science Center Objects

Landslides in the West Hills of Portland pose a hazard to people and property.

Recent Conditions

Instrument installation at this site took place during the summer and fall of 2006. These instruments are used to monitor and detect changes in local conditions, including:

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

Project Background

Landslides in the West Hills of Portland pose a hazard to people and property. In February 1996, a major storm induced hundreds of landslides in the West Hills. Smaller numbers of landslides occur every few years during extended rainy periods and intense storms.

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.

Installation of monitoring instruments in Portland hills

Photograph showing USGS scientist connecting sensor cables to data collection equipment.  The equipment is housed in a weather-resistant enclosure that is mounted on steel posts.  Flexible steel conduit protects the instrument cables from damage by wild animals that would chew the insulation.   (Public domain.)

Photograph showing installation of a tensiometer at the Portland monitoring site.

Photograph showing tensiometer (blue tube) being installed in inclined borehole.  (Public domain.)