SEISMIC HAZARD ASSESSMENT OF ENGINEERING SITE IN SHANGJIANG HYDROPOWER STATION OF JINSHA RIVER

Shangjiang Hydropower Station has not only complex regional tectonic background, but also high frequency of seismic activity, and the site seismic risk assessment is the key technical problem to be solved in this project. The study of regional geology, seismic structure and seismic risk shows that the frequency of regional destructive earthquakes and the level of seismic activity are very high, and 2 earthquakes of MS 7 occur in the region. The earthquake with magnitude 7 or so may still occur in the prediction area, 5destructive earthquakes with magnitude MS 4 ¾ occurring in the near field, the maximum magnitude being 6 ¼, and the earthquake with magnitude 6 or so likely to occur in the near field area. Because the dam site and its adjacent area are confined by active faults on the outer margin, and the site of the dam site is relatively stable for dam construction. Finally, according to the method of determining the relation of potential source area, seismic activity parameter and ground motion attenuation, the results of seismic hazard analysis and ground motion parameters of five kinds of probability beyond the probability level of dam site are calculated, which can provide engineering seismic basis for project design and construction.