Quake warning system offers vital seconds

CHINA has built an earthquake early warning system in Chengdu, capital of southwestern Sichuan Province, exploiting multiple broadcasting systems to alert citizens seconds before seismic waves arrive.

In a drill on Wednesday, an early warning was sent through radio, television and mobile phones to 60 residential communities in Chengdu High-Tech District.

“The earthquake early warning is not an earthquake forecast. The early warning system just uses the theory that radio waves travel faster than seismic waves to give people seconds of time ahead of the jolt,” said Wang Tun, head of the Sichuan Province Key Laboratory and Chengdu High-Tech Disaster Reduction Institute.

Wang said that aided with advanced technology from the Internet of Things, the system connected with the seismic network sends out the warning when shock waves are monitored so people have vital extra seconds to find shelter.

Earthquake research has found that being aware of an earthquake three seconds ahead can save 14 percent of casualties, 10 seconds can save 39 percent of casualties, and 20 seconds can save 63 percent of casualties.

In key sectors such as the chemical industry, nuclear industry, highspeed railways and urban metro systems, the earthquake early warning can substantially save losses and avoid secondary disasters, Wang said.

He added that Chengdu’s warning system currently covers 2.2 million square kilometers, where there are 660 million people.

The system makes China the third country after Japan and Mexico with an earthquake early warning ability.

In the magnitude 7 quake that rocked Jiuzhaigou County in Sichuan last August 8, the quake alert was sent out 71 seconds before the first seismic wave arrived.

China is building 2,000 monitoring stations in Sichuan and neighboring Yunnan Province to collect data on underground stress and energy 8-20 kilometers below the surface of the earth.