Reservoir triggered seismic phenomena are seismic events which needed the incremental effects of reservoir load and the build-up of pore pressure to make them happen. The problematic association between reservoir impoundment and seismic activity has been considered in the dam engineering community since 1935, when the first documented case of reservoir-triggered seismicity (RTS) was created by impounding the Hoover arch dam in the US. In view of other similar events, interest in this phenomenon grew. Although RTS only affects a small number of dams, it has remained controversial and the subject of much study due to associated environmental impacts and risk considerations. The effect of RTS on the seismic design of large dam projects and the possible effect of RTS on buildings, infrastructure and people living in the dam and reservoir regions, is discussed. As RTS usually occurs within a few years after impounding of the reservoir, it has an effect on the seismic hazard and design criteria for appurtenant structures, buildings and infrastructure but not on the ground motion of the so-called safety evaluation earthquake, used for designing and checking the seismic safety of dams. The prediction of the largest RTS events is still not possible but by seismic monitoring, irrational concerns about dam safety can be greatly reduced. The different aspects of RTS are discussed in the paper.
Large dam, reservoir, reservoir triggered seismicity, seismic design criteria, dam safety
