On April 14, a devastating 7.1-magnitude earthquake hit Yushu County in Qinghai Province. Before the quake, Yu Xianghong, a seismologist from Shaanxi Earthquake Administration, was said to have successfully predicted an impending quake of 5.0-5.5 magnitude around this area. Also, an amateur involved in earthquake prediction in Xi'an reported abnormal changes in his earthquake detecting equipment. These have caused much speculation and people are now wondering - can earthquakes really be predicted?

"There could be some correlation between earthquakes and signs showed by these prediction devices, but it is still not reasonable to regard a prediction technique as reliable if it succeeded once but failed on 99 other attempts," said An Meijian, researcher of Chinese Academy of Geological Sciences.

Shen Chongyang, researcher of Wuhan Institute of Seismology, told ChinAfrica there are indeed some successful cases, but on most occasions, accurate prediction is very difficult.

Earthquake prediction includes long-, mid- and short-term prediction. Substantive progress has been made in long- and mid-term prediction, but short-term earthquake forecasting remains a challenge due to the lack of scientific data and advanced technology.

The only successful case in world earthquake prediction history is the accurate forecast of Haicheng earthquake in 1975. The Chinese Government predicted the magnitude-7.3 earthquake from foreshocks and evacuated people before the quake hit. Thousands of lives were saved.

Shen attributed the successful prediction to the important precursor - foreshocks, which many other earthquakes do not have.

Nature's warnings

The magic of nature can be much more "earthquake sensitive" than technology. Evidence exits to show that animals can act abnormally before an earthquake, such as dogs barking wildly, rats and snakes leaving their nests and chickens stopping to lay eggs.

Besides animal behavior, there are other well-known precursors, such as sudden changes of well water levels and temperature, unusual movements of the earth's crust and the increasing emission of radon gas.

In 2008, many precursors appeared before the deadly earthquake hit Wenchuan in southwest China's Sichuan Province. Local media reported that tens of thousands of toads appeared on the road in Mianzhu, not far from the epicenter at Wenchuan while in Enshi City, Hubei Province, 80,000 tons of water in Guanyin pool disappeared in five hours.

Should government issue warnings based on natural warnings? Zou Xiaomei, a current overseas student from Chengdu thinks so. She said lives could have been saved in Wenchuan if a warning had been issued.

An disagrees. "Definitely they can't issue warnings," said An, adding that it could lead to social unrest and lack of credibility in the government if the warnings prove false.

When asked about the reliability of these natural precursors, An said it is possible but they can also be caused by other natural factors.

Shen also said some earthquakes do have precursors, but most of the correlations found between earthquakes and these natural phenomena are empirical in nature. Advanced explanations are still needed to account for the relationship between them.

Despite the arguments about nature versus technology both experts believe that with ongoing collection of data eventually this conundrum will be solved. An's confidence also pointed in the direction of prevention rather than prediction. "An earthquake is not that devastating so long as we have stable and earthquake resistant houses," he said.

History of Prediction Attempts

Source: Wikepedia-Earthquake Prediction