Earthquake Early Warning
Earthquake Early Warning (EEW) is the rapid detection of earthquakes, real-time estimation of the shaking hazard, and notification of expected shaking. EEW provides seconds to tens-of-seconds of notice before strong shaking starts, which can help reduce injuries, deaths, and property losses.
Natural Resources Canada (NRCan) is developing a national EEW system designed to enhance early detection and warning in areas of moderate to high earthquake hazard and concentrations of population and infrastructure. In Canada, this earthquake risk is concentrated along the west coast of British Columbia, the Ottawa River Valley, and the Saint Lawrence Seaway.
How EEW systems work
Earthquakes release energy that travels through the Earth as seismic waves. Seismic sensors detect the first energy to radiate from an earthquake, the P-wave, which rarely causes damage. The sensors transmit this information to data centres where a computer calculates the earthquake's location and magnitude, and the expected ground shaking across the region. This method can provide warning before the arrival of secondary S-waves, which bring the strong shaking that can cause most of the damage.
Earthquake graphical respresentation (Transcript)
When an earthquake occurs, its (generally weak but fast) P-wave travels rapidly from the epicentre, triggering the EEW system which then alerts people and systems before the (slow but strong) S-wave arrives. These seconds to tens of seconds of warning allow people and systems to take protective actions, such as stopping trains.
The EEW system will send out alerts
EEW alerts will be sent to the public through national alerting systems and other means. Government Operations Centres and Critical Infrastructure Operators may use notifications to trigger automated responses to protect people and property.
The EEW system is designed to alert for potentially harmful earthquakes, including for strong shaking from earthquakes outside Canada's borders. NRCan is therefore working with US partners, and will be using the United States Geological Survey’s EEW software.
Capabilities of EEW Earthquake Early Warning systems
EEW systems cannot predict earthquakes, but they can provide up to tens of seconds of warning by detecting an earthquake immediately after it occurs. In general, it is best to assume the shaking is imminent and take immediate protective actions.
Earthquakes generating only low levels of shaking will not produce EEW alerts. Additionally, sites very close to an earthquake’s epicentre may be in the event’s “late alert zone”, within which alerting is not possible.
EEW does not remove the need for other earthquake risk reduction, preparedness and response measures, such as constructing to building code requirements.
Safe response actions
Earthquake Early Warning alerts only reduce the impacts of strong shaking if people and systems take protective actions.
Recipients of an EEW alert should assume strong shaking is imminent. There are several protective actions people and organizations can take within seconds of notice. Some of these might be automated, in the case of critical infrastructure and other high-risk operations, triggering automated actions as shown below. For people, this will be to Drop, Cover and Hold On.
Possible preventative measures include:
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Drop, Cover and Hold on (alternative actions for specific situations will be added here soon) -
Automatically open fire hall and ambulance bay doors -
Stop traffic onto bridges and into tunnels -
Close valves -
Halt trains -
Divert planes from landing -
Move elevators to the nearest floor and open doors -
Halt surgery
Connect with us
For general information, contact the Earthquake Early Warning Program at 613-995-1006.
For media inquiries, contact NRCan Media Relations or the Earthquake Early Warning Program at 613-995-1006.
For more information on earthquakes in Canada, please visit Earthquakes Canada.