2024 RT Amination Banner.gif

China Daily

Asia Pacific> Global Weekly> Content
Saturday, July 20, 2019, 22:54
Saving lives in quake-prone areas
By Aybek Askhar in Xiamen, Fujian
Saturday, July 20, 2019, 22:54 By Aybek Askhar in Xiamen, Fujian

Coastal province of Fujian is at the forefront of the nation’s early warning program

A student relays information from an earthquake early warning terminal at Xinqiao Middle School in Jinjiang, Fujian province, last month. The terminal was provided by the Fujian Earthquake Agency. (SUN ZIFA / CHINA NEWS SERVICE)

The magnitude 6 earthquake that hit Yibin in the southwestern province of Sichuan on June 17 brought back distressing memories for Fan Chunmei, a businesswoman in Fujian province, as she recalled an earthquake that struck her hometown of Nantou, Taiwan, in 1999.

“Five days after the earthquake, I was on my way back to Nantou. As I drove along a mountain road, I saw many empty coffins in an open space and there was a big freezer on one side. Employees of the local funeral parlor told me that there were more than 2,000 unclaimed bodies in that freezer,” she said.

“As a Taiwan native, I am aware of the impact of earthquakes. Therefore, when the Fujian Earthquake Agency came to me and offered an earthquake early warning terminal, I did not hesitate to install it in my factory, even though I was not sure how it worked.”

The terminal is an important part of Fujian’s earthquake early warning system, and it is also a part of the National Seismic Intensity Rapid Reporting and Early Warning Project, a nationwide program approved by the central authorities in 2017.

About 60 seconds after the earthquake struck Yibin, it hit Chengdu, capital of Sichuan, but local residents had already been warned by the terminal, which resembles a self-service machine at a fast-food restaurant. It displays a range of information, including earthquake warnings, meteorological information and public notices that can save many lives.

The alarm is triggered within seconds of an earthquake hitting. Accompanied by a piercing siren, the screen gives a second-by-second countdown to the ground starting to shake, indicating how intense the aftershock will be.

Despite its success, the Fujian Earthquake Agency, aka the FJEA, noted the terminal only provides early warnings and cannot predict earthquakes.

Our knowledge of these natural phenomena is uneven. For example, meteorological experts can use satellites to determine the direction of cloud movements and predict landfall for typhoons, but the deepest shaft bored into the surface of the Earth is 12 kilometers, just 0.18 percent of the distance to the core.

However, that does not mean experts cannot learn about the Earth’s internal structure. By detecting the frequency of vibrations, seismologists can describe the structure of the crust, where tectonic plate movements produce earthquakes.

This movement generates two waves — the primary wave travels quickly, at about 6 kilometers a second, but has low destructive power, while the relatively slow-spreading secondary wave, at about 3 km per second, is the main force that triggers earthquakes. Because it travels at about twice the speed of the secondary wave, the primary wave is the main source of the early warning system.

The terminal provides the estimated time and intensity of an imminent earthquake several seconds before the destructive secondary wave arrives. Those precious seconds are enough to allow emergency measures to be taken.

Fan’s factory is the first private facility in Fujian to install the terminal. Last year, the province published plans to install terminals in 18,400 schools and communities, as one way of providing early warnings.

After the devastating 2008 earthquake in Wenchuan, Sichuan, which killed nearly 70,000 people, China began paying more attention to early warning technology for earthquakes. In August of the same year, the China Earthquake Administration submitted a national science and technology support program for early warning measures.

Since then, the FJEA has also played an important role in China’s early warning program.

The program, whose lead expert is a member of the FJEA, studies the key practical technology of seismic intensity rapid reporting, and earthquake early warnings are produced with strong support from the agency.

“Southwest China has the highest frequency of earthquakes, but Fujian (on the southeast coast) is also at high potential risk from such disasters. There are many epicenters in the Taiwan Straits that threaten us, and Fujian has suffered many earthquakes throughout history,” said Wang Qingping, chief designer at the FJEA’s Emergency Command and Publicity Center.

Seismic sensors in monitoring stations detect the waves that emerge from an earthquake before the temblor begins. To capture seismic data promptly and accurately, the stations need to be densely located in different areas.

“Fujian has the most advanced and widely distributed monitoring stations in China. By 2020, we will have more than 1,300 different types of monitoring stations across the province, which means one will be sited every 10 kilometers,” Wang said.

“In 2010, we began developing earthquake early warning software, and now we have an independently developed smartphone app. From the moment we receive the seismic data, it takes less than a second to send warning notifications to phone users.”

On Nov 26, a magnitude 6.2 earthquake struck in the south of the Taiwan Straits. The FJEA’s seismic publishing platform sent an early warning to 2,380 mobile phone users and 3,750 terminals just 8.6 seconds after the earthquake was triggered. Schools in some coastal areas quickly evacuated their students without stampedes or casualties.

“We have a class related to disaster prevention every Friday, and an evacuation drill every month,” said Wang Yichun, a student at Xinqiao Middle School in Jinjiang, Fujian.

“We also learn how to pitch a tent during our physical education classes. The exercises are fun, but more importantly, we get to know what to do after receiving an earthquake warning on the terminal or our phones.”

Guo Hao, director of the FJEA’s executive office, said: “Fujian is the first province in China to establish detailed rules and standards for earthquake early warnings, including regulations related to the main body of information release, trigger conditions and legal liability.”

The agency’s efforts mean that Fujian is at the forefront of the nation’s early warning program, and even the blue-and-white color scheme used on the exteriors of monitoring stations was pioneered by the FJEA.

In addition to improvements in early warning technology and legislation, more detailed data about the Earth’s crust is needed to further develop the system and support infrastructure improvements in earthquake-prone regions.

However, seismic waves that reflect the state of the Earth’s crust only occur during earthquakes, so, instead of waiting for the next temblor, seismologists produce “artificial quakes” to trigger waves and collect data without causing injury or damage.

Meanwhile, one project — a land-sea joint survey — has become an important program promoted by earthquake-prone countries.

While 80 percent of earthquakes in China occur under the sea, most of the nation’s quake and crust monitoring is conducted on land, so the ability to predict submarine temblors is underdeveloped. 

That has placed great emphasis on the land-sea joint survey, which focuses on the structure of the deep crust in Fujian and the Taiwan Straits, to support research into early warnings of oceanic earthquakes.

aibek@chinadaily.com.cn


Share this story

CHINA DAILY
HONG KONG NEWS
OPEN
Please click in the upper right corner to open it in your browser !