Last week, Taiwan was rocked by its most powerful earthquake in 25 years, registering a magnitude of 7.5 and a depth of about 35 km.
Over a dozen people were killed, more than 1,000 people were injured, and infrastructure and buildings were damaged or completely destroyed infrastructure and buildings, including tall structures that completely toppled over.
One of the most shared videos on social media from the earthquake was taken onboard the Taipei Metro network, when a visibly stopped train on an elevated rail segment with passengers onboard violently shook from the seismic waves.
Terrifying scene on the Taipei Metro during the Taiwan earthquake. pic.twitter.com/KHNMkp11F5
— Moshe Schwartz (@YWNReporter) April 3, 2024
Taipei Metro’s railway infrastructure is equipped with seismic sensors linked to alert systems, with the equipment installed in 15 stations on the train network. When there is an earthquake measuring a magnitude of four or higher, the system detects the seismic waves and issues alerts, enabling a rapid emergency shutdown of the trains when needed.
According to the Taipei Metro’s protocols, its earthquake procedures begin to kick in with earthquakes measuring a magnitude a 2.0, with greater safety measures taken for more powerful earthquakes of magnitudes 4.0 or higher. Each magnitude on the Richter scale represents an earthquake intensity that is 10 times stronger. For instance, this means a magnitude 7.5 earthquake is 10 times stronger than a magnitude 6.5 earthquake, and 100 times stronger than a magnitude 5.5 earthquake.
Depending on earthquake intensity, Taipei Metro’s protocols involve holding trains at the platform if the vehicles are already at the station, decelerating and/or slowly moving trains to the nearest station, evacuating passengers, and performing damage inspections.
TransLink’s fully-driverless SkyTrain network in Metro Vancouver also has an early-earthquake warning system.
All three SkyTrain lines — Canada, Expo, and Millennium — are linked to the University of Victoria’s Ocean Networks Canada’s (ONC) earthquake early-warning sensors, which are installed into the ocean floor just off the west coast of Vancouver Island. These undersea fault lines are frequently “ground zero,” where the epicentres of the most damaging earthquakes are expected to be located.
Currently, the $12 million invested to date by the provincial and federal governments into ONC system has provided an early-warning network eight seafloor sensors off the west coast of Vancouver Island and 40 land-based sensors across Vancouver Island.
The network of ONC sensors detects primary waves (P-waves) — the initial movements of the earth’s crust when an earthquake occurs. P-waves are generally non-damaging and are the precursor of the secondary waves (S-waves), which are the waves that cause damage. In order for an early-warning alert to be triggered, at least three sensors must go off to reduce the likelihood of false alerts.
![ocean networks canada earthquake early warning sensors map uvic](https://images.dailyhive.com/20240409182326/oceans-networks-canada-earthquake-early-warning-sensors-map-uvic.jpg)
Map of the sensor stations of Ocean Networks Canada’s (ONC) earthquake early-warning sensor system, as of June 2023. Click on the image for an expanded version. (University of Victoria)
In 2018, Daily Hive Urbanized reported that the Canada Line was the first SkyTrain line to be linked to the ONC sensors. Canada Line is separately and privately operated by SNC Lavalin’s ProTrans BC under contract with TransLink, and it has its own control room at the Canada Line’s Bridgeport operations and maintenance centre in Richmond.
Transmitted data from ONC sensors can provide a warning of between 20 seconds and 120 seconds ahead of the seismic waves of a powerful earthquake, which could prove to be lifesaving seconds enabling control room operators to deploy their quickly earthquake procedures. Canada Line’s operators have previously conducted real earthquake drills that slow down trains and hold them at stations in advance of the shaking.
The early warning not only provides the Canada Line with the ability to quickly stop trains but also enables the fare gates at stations to open.
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SkyTrain Canada Line’s North Arm Bridge over the Fraser River between Vancouver and Richmond. (Volodymyr Kyrylyuk/Shutterstock)
At the time, in 2018, it was stated that the ONC sensors could eventually be linked up to SkyTrain’s separate control room for the Expo and Millennium lines, located at the Edmonds operations and maintenance centre (OMC 1. The Expo and Millennium lines are operated by TransLink subsidiary BC Rapid Transit Company.
As it turns out, the linkage to the ONC sensors for the Expo and Millennium lines was quietly made in 2022.
“SkyTrain has installed the early earthquake warning system that was developed by Ocean Network Canada out of the University of Victoria. This system was installed in 2022 and SkyTrain was one of the testers of the system while it was being developed,” Dan Mountain, a spokesperson for TransLink, told Daily Hive Urbanized last week.
“In the event of an earthquake, this system will help SkyTrain Control staff quickly implement a system hold that keeps trains in station, making evacuation easier.”
![skytrain commercial broadway station platform f2](https://images.dailyhive.com/20240221185547/skytrain-commercial-broadway-station-platform-f2.jpg)
Expo Line platforms at SkyTrain Commercial-Broadway Station. (Kenneth Chan/Daily Hive)
According to the University of Victoria team that monitors ONC, their undersea sensors provided 43 seconds of advance notification to Vancouver and Victoria of the magnitude 4.8 earthquake that struck very close to Tofino on November 25, 2022. The cities were respectively 231 km and 235 km away from the epicentre, which was much closer to Vancouver Island’s shoreline than the area’s typical earthquakes. The epicentre was at a depth of 32 km.
“The 43 second notification was also independently verified by a sensor located along the Canada Line SkyTrain in Richmond as an operator is participating in the testing of ONC’s earthquake early system,” reads a bulletin by the team following the November 2022 seismic event.
Over time, the intention is to expand ONC’s linkages to more critical infrastructure, utilities, airports, hospitals, fire halls, schools, and other operators that would benefit from the early-warning alerts. An advance warning of even a few seconds could be a sufficient duration to not only stop trains, but also shut down gas lines, halt surgeries and pre-start hospital emergency generators, open the vehicle bay doors of fire halls and ambulance halls, abort incoming flight landings at airports, and alert students at schools and universities to take cover.
As well, this real-time early-warning system will eventually be connected to BC’s emergency alert system on television, radio, and smartphones, which has to date seen the most use with Amber Alerts issued by police.
![ocean networks canada earthquake warning sensors](https://images.dailyhive.com/20240409183156/ocean-networks-canada-earthquake-warning-sensors.jpg)
How ONC’s early-warning earthquake sensors work to provide advance alerts. (University of Victoria)
In 2020, the existing, soon-to-be-demolished Pattullo Bridge also saw the installation of the the short-term safety investment of an advance seismic and high wind warning system, including an automatic emergency bridge closure system with falling barriers on both the New Westminster and Surrey ends of the bridge deck to prevent further vehicles from entering during an imminent danger event.
TransLink’s previous studies indicate the old bridge would need to close by 2024 at the very latest given its rate of deterioration, and with its high safety risks that make it vulnerable to a catastrophic structural failure in the event of a powerful winds, a moderate earthquake, or a ship strike of the bridge’s unprotected in-river piers.
In 2026, just in time for the Broadway subway, TransLink is expected to reach completion and open a $110-million new state-of-the-art control centre building for the Expo and Millennium lines, located in Edmonds at OMC 2, across the street from OMC 1.
![pattullo bridge seismic wind advance warning](https://images.dailyhive.com/20200206185243/pattullo-bridge-seismic-wind-advance-warning.jpg)
Seismic and wind advance warning system on the Pattullo Bridge. (TransLink)
![pattullo bridge seismic wind advance warning](https://images.dailyhive.com/20200206185244/pattullo-bridge-seismic-wind-advance-warning-2.jpg)
Seismic and wind advance warning system on the Pattullo Bridge. (TransLink)