Data from earthquakes and explosions in the western and central parts of the Soviet Union are used to determine the values of the coefficient of anelastic attenuation of 1-sec period Lg waves from the Russian uplands region and for the region from the Caspian Sea to the southern perimeter of the Soviet Union. For the former region, the value is approximately 0.15 deg−1, and for the latter 0.35 deg−1.

Using the empirical Veith and Clawson (1972) curve for the amplitude of P waves at regional distances and theoretical curves for the attenuation of higher mode surface waves for Lg, curves are constructed which show the variation of the amplitude ratio of Lg to P with epicentral distance, with the coefficient of anelastic attenuation as a parameter. When data from explosions and earthquakes in the Soviet Union are compared with the calculated curves, the amplitude ratios of Lg and P on the average are larger for earthquakes than explosions. However, there is much overlap, so that this ratio by itself does not appear to be a useful discriminant between earthquakes and explosions.

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