Deliverables

ShakeAlarm®, Weir-Jones’ simple turn-key earthquake early warning solution, is composed of:

  • Seismic Sensors
    Passive triaxial seismic sensors installed on the foundation of an asset being protected
  • Data Acquisition Unit
    A processing unit converts the analogue sensor signals and transmits digitized information to the processing centre in real-time
  • Data Processing Center
    The controller for the structure being monitored is equipped with an industrial computer that runs P-Wave detection software. It directly interfaces with the
    available Safe-Shut-Down system. Threshold values are preprogrammed and ShakeAlarm® generates a Shake/No-Shake command in the event of excessive ground motion
  • Cable and connectors, user manual
  • Programmable Features
    • To generate audio/visual alarm
    • To send text message or email to any designated recipients
    • To activate a relay
    • To communicate with additional ShakeAlarm® networked units

 

Example

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.


Source: http://earthquake.usgs.gov/earthquakes/map/


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
11 sec.