Inspection of dams after earthquakes

Earthquakes may cause damage to dams in different ways:① strong ground shaking;② movements along faults and other discontinuities in the footprint of a dam;③ permanent loss of freeboard and water waves generated by fault movements in reservoir;④ impulsive waves due to mass movements into the reservoir.Major earthquakes may affect large areas and large numbers of dams.This was demonstrated by the 2001 Bhuj earthquake in India,where some 240 dams(mainly small embankment dams)were damaged and needed repair and strengthening.Also during the magnitude 8 Wenchuan earthquake in Sichuan province in China of May 12,2008,over 1580 dams and reservoirs were affected to different extents.Moreover,after the magnitude 7.2 Iwate-Miyagi Nairiku earthquake,which occurred in Japan on June 14,2008,134 dams were inspected.Therefore,in order to assess the safety of dams affected by earthquakes a thorough investigation is usually required by the dam safety authorities.This is done best by using checklists.In 2008 the 20 year old ICOLD Guideline on the Inspection of Dams Following Earthquakes was completely revised including the checklists for the inspection of embankment and concrete dams.The present paper provides a summary of the new features of this guideline and it is hoped that the checklists provided will be used not only for the inspection of dams after earthquakes but also for the general inspection of dams.