Q for 20-Second Rayleigh Waves from Complete Great-Circle Paths

Abstract

Seismograms of carefully selected large earthquakes recorded on the high-gain, long-period network were used to visually determine the amplitude ratio of 20-second Rayleigh waves in the R sub 1 and R sub 3 phases. Identification of R sub 3 was aided by applying a time-varying processor which discriminates heavily against ground motion other than the R sub 3 signal. Ratios were determined in 29 cases representing diverse great circles over the earth; and the average Q estimated for the 20-second, fundamental-mode Rayleigh waves was 498. This value is relevant to distance-amplitude corrections routinely made in M sub s calcualtions and is significantly greater than that Q implied by the current (1.66.) log delta relation. Our data did not reveal any significant difference in attenuation over oceanic and continental structures for 20-second Rayleigh waves.

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Document Details

Document Type
Technical Report
Publication Date
Feb 27, 1975
Accession Number
ADA015651

Entities

People

  • D. H. Von Seggern

Tags

Communities of Interest

  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Contracts
  • Data Analysis
  • Databases
  • Detection
  • Digital Data
  • Earthquakes
  • Epicenters
  • Group Velocity
  • High Gain
  • Identification
  • North America
  • Rayleigh Waves
  • Seismic Waves
  • Surface Waves
  • United States
  • Virginia
  • Waves

Readers

  • Computational Modeling and Simulation
  • Plasma Physics / Magnetohydrodynamics
  • Seismology