An earthquake early warning is displayed on a smartphone, Suqian, east China's Jiangsu Province, August 6, 2023. /CFP
A magnitude-5.5 earthquake jolted the city of Dezhou in east China's Shandong Province early on Sunday. Seconds later, smartphones in the surrounding areas began to emit a siren and display a full-screen countdown warning of an imminent earthquake.
This earthquake early warning system has saved many lives in China's earthquake-prone areas. The term "earthquake warning" became one of the most searched terms on Chinese social media platform Weibo in the hours following the Dezhou earthquake. Android users shared tips on how to enable the earthquake warning feature on their phones, while iOS users asked which app they could use to receive earthquake warnings.
Some people were confused about how humans could suddenly predict earthquakes. In fact, there is no reliable technology to predict earthquakes with certainty. However, China's earthquake early warning system can detect earthquakes as they happen and send out alerts to people in the affected area. This gives people a few seconds to take cover before the earthquake waves arrive.
This system works because radio signals – spreading at roughly the speed of light – travel faster than earthquake waves.
A display shows the sensor data related to the Shandong earthquake in a monitoring system in nearby Jiangsu Province, August 7, 2023. /CMG
The earthquake early warning system in China is the largest in the world. It consists of over 15,300 early warning stations, three national centers, 31 provincial-level centers, and 173 city-level message distribution centers. The system uses radio signals, smartphones and TVs to send out alerts.
The data collected by the earthquake early warning system can also help decision makers to take informed measures during a disaster. For example, the system can be used to identify areas that are at risk of damage, and to help authorities to evacuate people to safety.
Staff of the earthquake warning system check on sensor data in the control center, northeastern China's Liaoning Province, August 7, 2023. /CMG
Critical infrastructure such as railways, power stations, oil pipelines and dams can also be connected to the earthquake early warning system. This will allow these facilities to take steps to protect themselves from damage during an earthquake.
The government said they will fine-tune the system to increase accuracy and user-friendliness in the following years, and export the technology to benefit more people.