Earthquakes impose additional loads on to embankment dams over those experienced under static conditions. The earthquake loading is of short duration, cyclic and involves motion in the horizontal and vertical directions. Earthquakes can affect embankment dams by causing settlement and longitudinal and transverse cracking of the embankment, particularly near the crest of the dam. The settlements give a reduction of freeboard between the embankment crest and reservoir level which may, in the worst case, result in overtopping of the dam. Internal erosion and piping may develop in cracks. Liquefaction or loss of shear strength due to increase in pore pressures induced by the earthquake may occur in the embankment and its foundations. In short, earthquake loading may result in:

– Instability of the upstream and downstream slopes of the dam and large deformations.