t* for S waves with a continental ray path
- 1 August 1978
- journal article
- Published by Seismological Society of America (SSA) in Bulletin of the Seismological Society of America
- Vol. 68 (4) , 1013-1030
- https://doi.org/10.1785/bssa0680041013
Abstract
The purpose of this study was to determine t* for S waves with ray paths under the continental United States. The data set consists of long- and short-period body waves from the Borrego Mountain earthquake as observed in the northeastern U.S. The P wave forms are dominated by the sP phase and the SH wave forms by the sS. It is assumed that there are no losses in pure compression so that the relative attenuation rate of P and S waves is known. The initial source radiation is determined from the sP phase and the value of tβ* from the spectral content of the S wave. The results indicate that tβ* is 5.2 ± 0.7 sec along this ray path. Long- and short-period body waves from some deep South American events are used to test for lateral asymmetry of the Q distribution under the U.S. No lateral amplitude variation exists in this data, but this result is difficult to correlate with many previous results. The t°* value for a 600-km deep earthquake appears to be about 3 sec. A comparison of these values with values computed from current models of the Earth's Q distribution indicates that the models are slightly too high in Q overall and that more of the total body-wave attenuation occurs above 600 km than is indicated by the models.Keywords
This publication has 27 references indexed in Scilit:
- Measurements and interpretation of normal mode attenuationGeophysical Journal International, 1978
- Attenuation models of the earthPhysics of the Earth and Planetary Interiors, 1978
- Estimation of the attenuation operator for multiple ScS wavesGeophysical Research Letters, 1977
- Attenuative dispersion and frequency shifts of the earth's free oscillationsPhysics of the Earth and Planetary Interiors, 1976
- Spectrum and attenuation of multiply reflected core phases.Journal of Physics of the Earth, 1975
- Short period teleseismic S wavesNature, 1975
- Long and Short Period P-wave amplitudes from Earthquakes in the Range 0 -114Geophysical Journal International, 1974
- Study of teleseismic P II - amplitude dataPhysics of the Earth and Planetary Interiors, 1970
- Q Distribution for Long-Period P Waves in the MantleJournal of Physics of the Earth, 1968
- TELESEISMIC SIGNALS CALCULATED FOR UNDERGROUND, UNDERWATER, AND ATMOSPHERIC EXPLOSIONSGeophysics, 1967