Earthquake Protection
- Earthquake magnitude pipeline system designed to withstand
8.5 Richter Scale (maximum). Range from 5.5 to 8.5, depending on area.
- Faults crossed by pipeline
3 - Denali
McGinnis Glacier
Donnelly Dome
- Predicted limits of lateral movement for above ground pipeline, general
- 2 ft.
- Design values for maximum movement at pipeline crossing of major faults
Denali fault — 20 ft. lateral and 5 ft. vertical displacement
McGinnis Glacier fault — 8 ft. lateral and 6 ft. vertical displacement
Donnelly Dome fault — 3 ft. lateral and 10 ft. vertical displacement
Minor potential fault locations — 2 ft. lateral and 2 ft. vertical
- Earthquake Monitoring
Alyeska's Earthquake Monitoring System (EMS) consists of sensing and processing instruments at all pump stations south of Atigun Pass and at the Valdez Terminal. A central processing unit at the Operations Control Center (OCC) is linked to the Pipeline and Terminal operator consoles. The EMS is specifically designed to process strong ground motions, to interpolate or extrapolate estimates of earth quake accelerations between the sensing instruments and to prepare a mile-by-mile report comparing the estimated accelerations along the pipeline with the pipeline seismic design criteria.
- DSMAs
The instrumentation at field locations consists of accelerometers mounted on concrete pads which measure strong ground motions in three directions (tri-axial) which are connected to a Digital Strong Motion Accelerograph (DSMA). The DSMA, generally located in the Pump Station control room, processes the signals from the accelerometers in real time and reports alarms and selected data to the central processor at the OCC.