Prediction of the Haicheng earthquake

At 1936 LT, the evening of February 4, 1975. a magnitude 7.3 earthquake occurred near the town of Haicheng. Liaoning Province, in the People's Republic of China. This earthquake was widely felt through northeastern China and caused coniderable damage to existing structures and cultivated land in the epicentral region. Approximately 90% of the structures in Haicheng, a city of 90,000 people, were destroyed or seriously damaged at the time of the earthquake. Given the time of day, subfreezing ambient temperatures, and the population density through the region in which significant damage occurred, casualties in excess of 100,000 would have ordinarily been anticipated—had this earthquake not been predicted accurately enough to effect massive evacuation of the local population from their dwellings on the afternoon and evening of February 4. The prediction of the Haicheng earthquake is an extraordinary achievement of the seismological and geophysical workers of the People's Republic of China, whose national program in earthquake research was less than 10 years old at the time. At the same time the Haicheng earthquake was the first major shock to have been accurately predicted anywhere in the world, and our delegation is one of several groups of scientists whose trips to China have been highlighted by the accounts of this remarkable success.