Assessment of seismic risk is influenced by geology, tectonic factors, history of seismic activity, and by past experience with underground construction in the region indicating ground stability.  Seismic monitoring information should be collected and analysed in the evaluation of potential development sites, this information used to inform decisions with regard to the most appropriate construction techniques that are appropriate to the geodynamics of the area.

In order to conduct such an analysis it is necessary to access reliable geological mapping information supported by topographic data at the dam site, and similar information at a coarser scale for the reservoir area.  Aerial photography can also be used to reveal if the location has been subject to previous landslips or similar earthquake disturbance.  This information, together with a geological survey of the site, is combined with monitoring records of any seismic activity in the region to determine the probability of a seismic event. 

The level of earthquake chosen as a basis of a deterministic (risk) analysis is usually measured in terms of estimated return period.  Risk is usually based on an assessment of return periods of 72, 475 and 975 years.  These years correspond to 50, 10 and 5 percent probability of a similar event occurring within a 50-year period, which is often the design life of a structure (see ASTM standard E2026-99).   

Once a site has been selected, instrumentation can be installed to monitor dam movement and structural integrity following construction.  This instrumentation should form part of a robust, strategically located, seismic network coupled to an analysis process that produces prompt reports of seismic activity and informs dam safety emergency plans.