A staff member takes cover under the table inside the Canada Line's control room during the "Great Shakeout" earthquake exercise in Vancouver, Canada, on Oct. 18, 2018. About 910,000 people participated in the annual "Great Shakeout" earthquake exercise in British Columbia of Canada. A simulated exercise conducted by Canada Line - Vancouver's driverless, computer-controlled train system, to practice how the transit operators and residents react after the earthquake early warning system issue alert. (Xinhua/Liang Sen)

A staff member takes cover under the table inside the Canada Line's control room during the "Great Shakeout" earthquake exercise in Vancouver, Canada, on Oct. 18, 2018. About 910,000 people participated in the annual "Great Shakeout" earthquake exercise in British Columbia of Canada. A simulated exercise conducted by Canada Line - Vancouver's driverless, computer-controlled train system, to practice how the transit operators and residents react after the earthquake early warning system issue alert. (Xinhua/Liang Sen)

People take cover under the table during the "Great Shakeout" earthquake exercise in Vancouver, Canada, on Oct. 18, 2018. About 910,000 people participated in the annual "Great Shakeout" earthquake exercise in British Columbia of Canada. A simulated exercise conducted by Canada Line - Vancouver's driverless, computer-controlled train system, to practice how the transit operators and residents react after the earthquake early warning system issue alert. (Xinhua/Liang Sen)

A staff member responds to a simulated earthquake early warning signal inside the Canada Line's control room during the "Great Shakeout" earthquake exercise in Vancouver, Canada, on Oct. 18, 2018. About 910,000 people participated in the annual "Great Shakeout" earthquake exercise in British Columbia of Canada. A simulated exercise conducted by Canada Line - Vancouver's driverless, computer-controlled train system, to practice how the transit operators and residents react after the earthquake early warning system issue alert. (Xinhua/Liang Sen)