Regional Attenuation of Short-Period P and S Waves in the United States
Abstract
Regional distribution of anelastic attenuation beneath the United States was investigated using amplitudes and dominant periods of short period P and S waves originating from deep focus earthquakes in South America and the Circumpacific seismic belt, recorded at LRSM (Long Range Seismic Measurement) stations. The observed regional distribution pattern shows high attenuation in the western United States, including California, and a less pronounced high attenuation region in the northeastern United States. This distribution pattern is similar to that reported by Solomon and Toksoz (1970) for long period S waves, but differs from it sufficiently to indicate lateral variations in the frequency dependence of the average crust-upper mantle attenuation across the United States. The relative changes of short period P and S wave amplitudes can be sufficiently explained by assuming a complex shear modulus, no losses in compression are indicated.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 22, 1974
- Accession Number
- AD0776672
Entities
People
- John P. Gurski
- Robert P. Masse
- Zoltan A. Der