Why Earthquakes Can Be Predicted ?

Just think about the following questions: If people asked a scientist wheather a typhoon could be forecasted 100 years ago, what would be the answer ? If we have not been tried for many many years to forecast the weather, could we have our today's weather forecasting theory and the effective forecasting system ?

Earthquake prediction is just in the same position as weather forcasting some 100 years ago. In north America, some scisntists who want to study in this area do not have enough resources to do it; other scientists who may be in better positions do not believe it could be done; so the research works in this area is very limited.

However, earthquake prediction has been studied and tried seriously for more than 30 years in China. Supported by the government, some ten thousand people (most of them are highly trained but poorly paid) are working in the area of earthquake prediction. Although imminent forecasting is still a problem, a lot of sucessful short-term forecasting (several weeks to several months early) and mid-term forecasting (several months to one year early) are reported. The only imminent forecasting for a strong earthquake (M=7.2) was reported in China in 1972. Some ten thousand lifes were saved due to that forecasting. There may be some coincident existed in that forecasting, but if we did not even want to try, nothing could ever happen.

But,Is there any theorical foundations for earthquake prediction ?
Yes. Earthquakes are caused by deformation of rock layyers (usually along a fault or a fault zone). By monitoring the deformation directly or indirectly, earthquakes can be predicted. Since the bigger and more destructive an earthquake is, the more deformation would happen and shallower the earthquake focus would be; therefore, we will have a better chance to predict it (in most cases).