One well-known successful earthquake prediction was for the Haicheng, China earthquake of 1975, when an evacuation warning was issued the day before a M 7.3 earthquake! In the months preceding this earthquake, changes in land elevation, widespread reports of peculiar animal behavior, and many foreshocks had led to a lower-level warning.  An increase in foreshock activity triggered the evacuation warning.  Unfortunately, most earthquakes do not have such obvious precursors. In spite of their success in 1975, there was no warning of the 1976 Tangshan earthquake, magnitude 7.6, which caused an estimated 250,000 fatalities.