The Damage Potential of Eastern North American Earthquakes

We compare the damage potential of three recent eastern North American (ENA) earthquakes (Nahanni, 1985; Saguenay, 1988; and Mont Laurier, 1990) to that of the 1989 Loma Prieta, California earthquake. The Saguenay and Mont Laurier events were noteworthy due to their unusually high stress drops. The comparisons are based on synthetic ground motion records generated by the stochastic method, using source and attenuation models that were derived from actual records for each event. Damage potential is characterized by inelastic strength demand spectra, obtained by analyzing the response of nonlinear oscillators to each record. There is a strong similarity between the inelastic spectra and the more familiar elastic response spectra, although some significant differences are observed. Comparisons between events show that a moderate high-stress ENA earthquake, like Saguenay, can be as damaging to high-frequency structures as a major California earthquake.