Pacific Northwest Geodetic Array
Central Washington University

Real-Time Network in the Pacific Northwest

Tolt Dam: A Proactive Approach to Hazard Warning Systems

GPS Offset (cm)

Tolt Dam real-time GPS experiment:
Five CORS GPS receivers with tilt sensors mounted across Tolt Dam and co-located with WSRN Real-time Network Station LSIG GPS. In June of 2008 this system registered a California earthquake.


Wide-scale monitoring of dams around Washington State will enable emergency personnel to refine rescue and mitigation tactics in response to natural hazards.

RTN GPS with Dam Monitoring GPS

Real-time plot of current GPS measurements on the Tolt Dam.
*Compatible with browsers employing modern industry standards for plotting maps and data streams such as: Safari, Google Chrome, Mozilla Firefox and Opera.

Positions are computed and stored at the PANGA Lab facility of Central Washington University in Ellensburg, WA. These data are uploaded every second providing an instantaneous view of ground deformation that can lead to structure failure. Greater Seattle area hazard assements and warnings can thus be accurately made in relative safety away from most major geologic hazards of the Puget Sound region. Important since the warnings will be free from data disruptions and system failures that would otherwise be unavoidable if the lab was located within the forecast area.

Tolt Dam
GPS Install
GPS Locations

Real-time data will allow determination of rapid network offset soltuions, preparing dam and emergency personnel.

Wide Angle of Instrument and Dam