ShakeAlarm®, Weir-Jones’ simple turn-key earthquake early warning solution, is composed of:
ShakeAlarm® installed at the George Massey Tunnel in Richmond, British Columbia, records magnitude 6.3 and 5.6 quakes near Queen Charlotte Island on November 17,
2009. The signature of the P-Wave was autonomously analyzed in less than a second, and the risk analysis algorithm determined that the yet to arrive S-wave would not
create hazardous conditions at the tunnel.
Parameters of the first earthquake:
15:30:46 UTC. M=6.6, Latitude:52.151N, Longitude:131.49 W,
Depth: 10 km, Hypocentral Distance: D700km, Distance in Degrees: Δ6.3
IASP-91 travel time curves are used to compute P- and S-waves arrivals.
They are: t (p-wave) = 1 min 30 sec. t (s-wave) = 2 min 41 sec.
S-wave/P-wave time difference = 1 min 11 sec.
Based upon the November 17 2009 event, the effective amount of warning time to
vacate structures, shut down infrastructure or seek cover would have been: 1min