Earthquakes occur when rocks slip along a fault in the Earth’s crust. These seismic events primarily happen along active faults that delineate the Earth's major tectonic plates. They are caused by the slow deformation of the outer, brittle portions of tectonic plates. The movement and deformation of these plates, driven by the heating and cooling of rocks beneath them, can lead to the accumulation of immense energy. When this stress becomes too great, faults can suddenly rupture, releasing stored energy in the form of seismic waves and ground shaking.
Earthquakes are unpredictable and unavoidable. However, if detected rapidly, it is possible to estimate the earthquake magnitude using the Richter scale and predict the ensuing amount of shaking felt at various locations. This is the basis for establishing an Earthquake Early Warning System (EEWS). When an earthquake is detected, sensors on the ground assess the amplitude of seismic waves. If the amplitude surpasses a predefined threshold, alerts are issued. These precious seconds of early warning can enable crucial preventive measures to be implemented, such as evacuating buildings, halting traffic on bridges and in tunnels, stopping trains, redirecting planes, and pausing; potentially saving lives and minimizing damage.
Professor Pascal Audet, in collaboration with Claire Perry, a Research Scientist at Natural Resources Canada’s (NRCan) Canadian Hazards Information Service, and Master’s student Erica Pietroniro, is at the forefront of research aimed at enhancing Canada’s EEWS. The EEWS consists of a network of over 300 accelerometer sensorsstrategically placed in seismically active areas, including the greater Vancouver area, Ottawa, and Western Quebec. Scheduled for operation in April 2024, the EEWS aims to provide rapid earthquake detection, real-time hazard estimation and timely alerts of expected shaking.
Erica Pietroniro’s research project focuses on site characterization by analyzing the waveforms and metadata collected from these sensors. Each site where sensors are installed may have different geology at the surface depending on the region and location. Very soft ground can amplify the shaking, while rigid ground can reduce it. By understanding the geological composition of different sites, they can assess how ground conditions affect seismic amplification. This knowledge is crucial for accurately predicting ground shaking.
Further testing is necessary to ensure the reliability of the system, particularly in scenarios where satellite data may be disrupted. Once operational, the Earthquake Early Warning System will serve as a vital safety tool, empowering Canadians to mitigate the impact of earthquakes and safeguard lives and infrastructure.
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