The problem of earthquake risk in Chile is discussed in terms of seismic history, geotectonic provinces and regional variations in earthquake incidence. Seismic zoning is impractical because all of Chile above Parallel 42° South has been within the epicentral area of some destructive earthquake.
The probability concept of earthquake risk is discussed in reference to the seismicity of Santiago. It is found that the earthquake risk at Santiago for an acceleration of 0.1 g is 62.5% in any 10-year period. For the same interval, the risk of a “destructive” earthquake (intensity 8 1/2) is of the order of 20%.