Slope Movement Sensor
Graphs of slope movement show the cumulative downslope displacement, in centimeters, of the landslide relative to adjacent stable ground. Measured motion is downslope parallel to the ground surface; positive values indicate downslope movement. Sensor uses a linear position transducer with an extendable steel cable (extensometer). The instrument is anchored on stable ground and the end of the extendable cable is anchored on the slide. Sharp spikes in the graph are typically caused by snow loading; the cable extends when covered by snow and reverts to its original position when the snow melts or falls from the cable. Landslide movement is usually indicated by slow increasing displacement over many days.
WARNING: Provisional data, subject to revision
NOTE - data available since March 22, 1997