The Mainland Earthquake Warning Center issued a warning before the seismic waves of the Yibin earthquake arrived. Why was it so fast?

Earthquake early warning is not equal to prediction, and earthquake prediction is currently not possible in China

Experts believe that China has been able to issue earthquake early warning in time after an earthquake occurs, but earthquake prediction is an internationally recognized problem , it is currently not possible in China.

In this earthquake, the Mainland Earthquake Early Warning Network jointly built by the Chengdu High-tech Disaster Reduction Research Institute and the emergency management department issued early warning information after the earthquake. "A 10-second advance warning is given to Yibin City, a 43-second advance warning is given to Leshan, and a 61-second advance warning is given to Chengdu."

According to reports, Yibin City, Leshan City, Chengdu City, Liangshan Prefecture, and Deyang City in Sichuan Province 212 schools including , Meishan City, Ziyang City, Ya'an City, and Zhaotong City in Yunnan Province issued warnings ranging from 0 seconds to 57 seconds in advance. The reporter found that on December 16 last year, a magnitude 5.7 earthquake also occurred in Xingwen County, Yibin City, Sichuan Province, with a focal depth of 12 kilometers. After half a year, another earthquake occurred in Changning County, Yibin. Yan Rui, a researcher at the Earthquake Forecasting Department of the China Seismological Network Center, said that Changning County is not located in a major seismic zone, but it is also near one.

Currently, China has been able to issue timely earthquake early warnings after earthquakes occur. However, earthquake prediction is an internationally recognized problem and it is currently not possible in China. "There is an essential difference between earthquake early warning and earthquake forecasting." Yan Rui said that earthquake early warning refers to the fact that an earthquake is occurring at the epicenter but before it causes damage to the surrounding areas. It uses the principle that radio waves are faster than seismic waves. After an earthquake is detected, it is quickly Before the arrival of seismic waves, an early warning is given to the target area from a few seconds to tens of seconds in advance. The advance time of early warning is related to the distance between the target area and the epicenter. The further away from the earthquake source, the more time can be advanced. The developer of the earthquake early warning system asked relatives and friends to raise millions to do this after the Wenchuan earthquake

The early warning system that outperformed the Yibin earthquake swept the Internet, and the developer of this system also came into public view. He is Wang Dun, director of the Sichuan Provincial Key Laboratory of Earthquake Early Warning and director of the Chengdu High-tech Disaster Reduction Institute. Since returning to China in 2008, Wang Dun has been committed to "racing" against seismic waves.

The research and development of the earthquake early warning system began in 2008. When the Wenchuan earthquake occurred in 2008, Wang Dun was engaged in postdoctoral research in theoretical physics at the Austrian Academy of Sciences. Academic tycoon Wang Tun has obtained a bachelor's degree in engineering from Zhejiang University, a doctorate in mechanics from the Institute of Mechanics of the Chinese Academy of Sciences, and a doctorate in theoretical physics from the University of Connecticut. His original goal was to be a university professor. But after seeing the casualties caused by the Wenchuan earthquake, Wang Tun, who was born in Sichuan, came up with the idea of ??developing an earthquake early warning system.

Less than a week after the Wenchuan earthquake, Wang Tun took 3 million yuan raised from relatives and friends to Chengdu to start earthquake early warning research. Earthquake early warning relies on time difference. The basic principle of the earthquake early warning system is to take advantage of the fact that seismic waves propagate slower than radio waves after an earthquake occurs, quickly collect epicenter signals after an earthquake occurs, and issue early warning before the seismic waves reach the damaged area. Wang Tun led a team to use this principle to develop an earthquake early warning system.

At the end of 2010, Wang Tun led the team to complete the prototype of the earthquake early warning system and deployed the instrument for experiments in the aftershock area of ??the Wenchuan earthquake. In 2011, for the first time in China, it was possible to receive earthquake early warning information via mobile phone text messages, confirming that the technology was basically successful. In 2012, Wenchuan TV Station launched the country's first TV warning function. Before the earthquake wave arrives, the TV will automatically pop up a pop-up window and start a countdown.

After the 4.9-magnitude earthquake in Qiaojia, Yunnan Province in February 2013, the earthquake early warning system developed by Wang Tun achieved successful early warning. This was the first time that a domestic earthquake early warning system successfully warned of a devastating earthquake. After the 7.0-magnitude earthquake occurred in Lushan, Sichuan on April 20 of the same year, the earthquake early warning system successfully warned again.

For the Yibin earthquake, the system also drew a rapid intensity map for the government and emergency departments to make emergency disaster relief decisions.

When an earthquake occurs, special emergency earthquake early warning terminals installed by the National Seismological Network Center, National Disaster Reduction Center, National Early Warning Information Release Center, Sichuan Provincial Department of Emergency Management (Emergency Command Hall), Sichuan Provincial Disaster Reduction Center, Sichuan Provincial Fire Corps, etc. Receive earthquake early warning information and provide timely assistance in emergency response. An early warning time of 3 seconds can reduce casualties by 14%

Preliminary statistics show that Zhaotong City in Yunnan Province, Yibin City in Sichuan Province, Leshan City, Liangshan Prefecture, Deyang City, Chengdu City, Meishan City, Ziyang City, and Ya'an Schools in the city and other cities issued early warnings, 180 schools and 110 communities in Chengdu received early warnings, and 13 districts and counties in Yibin City, Leshan City, and Chengdu City that have opened radio and television earthquake early warnings and Internet television earthquake early warning prompts . Four rural towns and villages in three counties, including Zhaotong City in Yunnan Province, Yibin City in Sichuan Province, and Ya'an City in Sichuan Province, issued early warnings 7 seconds to 65 seconds in advance. "Don't underestimate the time from a few seconds to tens of seconds," Wang Tun said. Research shows that when the warning time is 3 seconds, casualties can be reduced by 14, when the warning time is 10 seconds, casualties can be reduced by 39, and when the warning time is 20 seconds, casualties can be reduced by 14. reduced by 63. During the Wenchuan earthquake, if there is an early warning, Beichuan can be given a 31-second warning time and Qingchuan can be given a 55-second warning time. If there are these early warnings, the number of deaths can be reduced by 20,000 to 30,000, that is, the deaths of 30 people can be reduced.

Chengdu High-tech Zone cooperated with Chengdu High-tech Disaster Reduction Research Institute to fully activate earthquake early warning "big speakers" in 60 communities, accounting for 80 of the total communities in Chengdu High-tech Zone. Communities with earthquake early warning "big speakers" built on the roof will broadcast early warnings before earthquakes reach the community, thereby ensuring the safety of community residents and effectively reducing casualties and property losses. At the same time, the Chengdu High-tech Disaster Reduction Research Institute will also release early warning information to community residents through mobile phone text messages, television and other channels to achieve multi-channel, wide-coverage earthquake early warning services.

Currently, the main channels through which the public can get early warning information as soon as possible include: through radio and television; installing the “earthquake early warning” App on smartphones, or installing apps with earthquake early warning functions; special earthquake early warning receivers terminal.