Tangshan,1976 China has a long history of earthquake. In fact, the first machine to measure earthquake was made by a Chinese scientist in the second century AD. In moden times,scientists use the Richter scale,which gives earthquake a number from 0 to 10. Every day in the world there are about 1,000 small Vs at level 2 that people do not notice; at the other end of the scale, the strongest earthquake in the history of the world, which happened in Chile in 1960,measured 9.5 on the Richter scale.