PORTLAND, Ore. » University of Washington researchers are testing an earthquake alert system as the Pacific Northwest prepares for the day when a 600-mile-long fault line looming off the coast unleashes a catastrophic earthquake and tsunami.

The fault line hasn’t produced a major quake since 1700, but seismologists say one could happen in our lifetimes.

Fears of such a quake have fueled development of a computer alert system that officials hope will save lives and protect infrastructure by giving a precious heads-up to get ready.

The ShakeAlert system uses seismic sensors to detect harmless, fast-moving signals that precede stronger waves that produce violent shaking during a quake. The system can calculate the magnitude of the quake before the shaking starts.

ShakeAlert’s architects say it could be completed in three years with increased funding.