11. Attenuation of Rayleigh Waves Along the East Pacific Ridge

  1. George H. Sutton,
  2. Murli H. Manghnani,
  3. Ralph Moberly and
  4. Ethel U. Mcafee
  1. E. Kausel1 and
  2. F. Schwab2

Published Online: 17 MAR 2013

DOI: 10.1029/GM019p0133

The Geophysics of the Pacific Ocean Basin and Its Margin

The Geophysics of the Pacific Ocean Basin and Its Margin

How to Cite

Kausel, E. and Schwab, F. (1976) Attenuation of Rayleigh Waves Along the East Pacific Ridge, in The Geophysics of the Pacific Ocean Basin and Its Margin (eds G. H. Sutton, M. H. Manghnani, R. Moberly and E. U. Mcafee), American Geophysical Union, Washington, D. C.. doi: 10.1029/GM019p0133

Author Information

  1. 1

    Departamento de Geofísica, Universidad de Chile Santiago, Chile

  2. 2

    Institute of Geophysics and Planetary Physics, University of California Los Angeles 90024

Publication History

  1. Published Online: 17 MAR 2013
  2. Published Print: 1 JAN 1976

ISBN Information

Print ISBN: 9780875900193

Online ISBN: 9781118663592

SEARCH

Keywords:

  • Geophysics—Pacific area—Congress;
  • Woollard, George Prior, 1908

Summary

Rayleigh-wave phase-velocity dispersion curves have been obtained with the single-stationmethod for a number of paths across the Pacific Ocean. Very low phase velocities are found for paths in the vicinity of the axis of the East Pacific ridge. Inversion of the dispersion curves shows that the East Pacific rise is characterized by abnormally low upper-mantle S-wave velocities, ranging between 3.8 and 4.1 km/sec in the low-velocity channel, and by a very thin lid, which may even be absent along the axis of the ridge. If the S-wave channel velocities are related to near-melting-point temperatures, low Qvalues should be expected in the LVZ under the ridge. A comparison of the relative shape of the amplitude spectra of Rayleigh waves for eight different paths suggests abnormally low Q-values in the vicinity of the ridge crest in a region having a thickness of about 40 km and starting at a depth of 20 to 30 km below the M discontinuity.