For an earthquake early warning system every second counts

On June 1, 2022, earthquakes of 6.1 magnitude and 4.5 magnitude hit China’s Lushan County and Baoxing County of Ya’an Municipality in Sichuan Province in quick succession, killing four people while injuring 42. The earthquakes are the aftershocks of the 2013 Lushan M7.0 earthquake which killed 196 people and injured 11470.

The June 1 earthquakes reminded me of what I had experienced eight months ago while I was visiting Ya’an for a World Bank-supported earthquake reconstruction project. Early in the morning on September 16, 2021, I was woken up in my hotel bed at about 4:30 a.m. by a booming voice from a loudspeaker in the street, counting down, “…12, 11, 10… 4, 3, 2, 1.” Immediately after I heard “1,” my bed started to shake for a few seconds. I jumped out of my bed and ran to the window. There was no panic on the street, so I decided to go back to bed. Next morning, I read the news of an earthquake in Luzhou Municipality of Sichuan Province, about 250 km from Ya’an. I was informed that the loud voice I heard was a 15-seconds early warning system for the community.

After the devastating Wenchuan earthquake in 2008 （which killed nearly 70,000 people and caused widespread damage), China has invested heavily in disaster preparedness in earthquake-prone areas. The research and development of the country’s earthquake early warning technology has advanced significantly since then. Sichuan Province, which is exposed to a high risk of earthquakes, started piloting an early warning system (EWS) in a few communities in its capital city of Chengdu in 2012. By the end of 2020, the entire province was covered by the system.

Especially in Ya’an and Meishan Municipality, the EWS is accessible down to the village level. Warnings can be heard from loudspeakers in the street, seen on TV, heard on radio, through cell phone apps and other media channels. The closer you are to the epicenter, the shorter notice you will receive – from nearly a minute to just a few seconds in advance.  A few seconds may seem short, but they save lives at critical moments. During the most recent earthquake in Lushan County, early warning was given 4 seconds after the earthquake took place, which allowed early warning of 9 seconds in Ya’an and 29 seconds in Chengdu. The Northwest Seismology Journal in China reported that an early warning of three seconds could reduce death and injury rates by 14%, a 10-second early warning could bring this rate down by 39%, and 20 seconds could mean 63% lower levels of injury. Had such a system been available during the 2008 Wenchuan earthquake, death rates could have been reduced by 30%.

At the World Bank, we are implementing the Lushan Earthquake Reconstruction and Risk Reduction Project with a loan of US$ 300 million, which helps a number of counties mainly in earthquake-prone Ya’an Municipality, including Lushan and Baoxing. In addition to upgrading urban and rural resilient and emergency infrastructure, the project also supports the pilot of a disaster risk management (DRM) system in Shimian County, and the establishment of a disaster control and command center within the county’s emergency response office. The DRM system has been later on scaled up during the project restructuring to cover the entire Ya’an Municipality to improve efficiency and impact.

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