BEIJING: Scientists in China are calling for improvements in earthquake prediction, including the establishment of an early-warning system and methods to share quake information.

The calls come after the 12 May Sichuan earthquake, which was the most serious to strike the country in three decades.

Ni Sidao, a professor of geophysics at the University of Science and Technology of China, said that although current scientific methods cannot accurately predict an earthquake, an early-warning system could alert people to leave for open spaces before buildings are destroyed.

Warning window

Ni made his remarks at the China Science and Humanities Forum in Beijing, operated by the Graduate University of the Chinese Academy of Sciences.

He said that P waves – which are early, less destructive seismic waves – could be used to detect and calculate the scale of an earthquake within ten seconds with the aid of computers.

In the case of Sichuan, later, more destructive seismic waves (S waves) took 30 seconds to reach the most severely hit region (Beichuan 90 km north of the epicentre) and nearly 100 seconds to reach Qingchuan County, 200 km from the epicentre.

People in Beichuan could have had at least a ten-second warning of the earthquake with an early warning system, which might have allowed some people to move outdoors and allowed trains to stop to prevent derailing, said Ni.

But he admitted that current seismic monitoring stations in most parts of China are too isolated to form a warning network.

Ren Luchuan, a senior researcher at China Earthquake Networks Centre (CENC), welcomes Ni's suggestions, but said that such a system would be very difficult to operate.

"[The time difference between P and S waves] is so short that it's very hard to establish a system to notify residents," he said. However, such a system could be used for key sites such as nuclear power stations, which could close reactors, he added.

Longer-term prediction seems to be just as fraught with problems.

Hot hints

In the 28 May issue of the Chinese language journal Science and Technology Review, experts led by Wu Lixin from the Chinese University of Mining and Technology in Beijing, report an abnormal temperature rise in the thermal satellite images of the eastern front of Qinghai–Tibet plateau – the fault that caused the earthquake – 20 days before the Sichuan earthquake.

The authors suggested this rise could be caused by tectonic plate movement, and could be an indicator for earthquake prediction.

But Ren said many factors could cause the abnormal temperature increases, leading to uncertainty in using temperature change to predict earthquakes.

In a separate article published in the same issue, however, Wu writes that there should be more intensive, accurate and consistent analyses of thermal satellite images, and that these should be frequently checked against seismic wave monitoring.

In addition, he said an earthquake information sharing system should be established, so that general researchers can analyse or input data about abnormal observations into a system for professional seismologists to screen.