
However, there has been only one instance of accurate prediction—in China way back in 1975. An earthquake of magnitude 7.3 was predicted in Haicheng a day before on the basis of changes in ground water level, foreshock activities, animal behaviour and elevation in ground level. The area was immediately evacuated. However, the failure in predicting two earthquakes in China the very next year pointed out the need of detailed research on the behavior of precursors.