Ground motions from eastern North America earthquakes: How strong are they?
Over the past decade there has been a growing recognition of the nature of seismic hazard in eastern North America. Eastern earthquakes are less frequent than their western counterparts but may have enormous damage potential, for two reasons. The first and most clearly documented reason is that the decay of ground motion amplitudes with distance is less rapid in the east than in California; thus a large eastern earthquake may damage structures over a broad area. The second reason is that the stress drops of eastern earthquakes, which control the strength more than a factor of two greater than western stress drops. As a result, the ground motion amplitudes over the high-frequency range (5 to 10 Hz) are much greater for eastern earthquakes than for western earthquakes of the same size. Considering both of these factors, the damage potential of moderate eastern events, such as the magnitude 6 earthquake that occurred near Chicoutimi, Quebec in 1988, is comparable to that of larger California events, such as the magnitude 7 Loma Prieta earthquake of 1989. Consequently many eastern cities have a significant probability of experiencing damaging ground motions.
- OSTI ID:
- 549184
- Report Number(s):
- CONF-950264--
- Country of Publication:
- United States
- Language:
- English
Similar Records
Ground-motion attenuation and earthquake source scaling in eastern North America. Final report
Earthquakes in Nevada triggered by the Landers, California earthquake, June 28, 1992