1973/02/10 by Otto W. Nuttli · 3 citations
Earth and Planetary Sciences · Mathematics · #Seismic Waves and Analysis #earthquake and tectonic studies #High-pressure geophysics and materials #Magnitude (astronomy) #Attenuation #Amplitude #Richter magnitude scale #Rayleigh wave #Range (aeronautics) #Geology #RADIUS #Seismology #Rayleigh scattering #Seismogram #Geodesy #Physics #Surface wave #Geometry #Mathematics #Optics #Scaling #Materials science #Astrophysics
paper · doi:10.1029/jb078i005p00876
openalex publication_date 1973/02/10 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06
Observational data on the attenuation of short-period Rayleigh waves in North America east of the Rocky Mountains yield the following average values for the coefficient of anelastic attenuation: γ = 0.07 deg−1 for 1-sec-period waves and γ = 0.10 deg−1 for waves with a maximum particle velocity in the period range 3–12 sec. By way of comparison, the amplitude data that form the basis of Richter's empirical local magnitude scale for southern California give γ = 0.60 deg−1. Differences in γ values are sufficient to explain the observation that earthquakes in the eastern United States have a radius of perceptibility as much as 10 times larger than that of earthquakes of the same magnitude in the western United States. Theoretical curves of log A/T versus log Δ are not linear. Thus magnitude formulas of the type M = B + C (log Δ) + log A/T are valid only over a limited range of distance, for which the curve can be approximated by a straight line. Formulas of this kind, which give mb and Ms from short-period Rayleigh waves, are proposed for eastern North America.