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Science 24 March 1978:
Vol. 199. no. 4335, pp. 1333 - 1335
DOI: 10.1126/science.199.4335.1333-a
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Articles

Spectral Analyses of High-Frequency Pn and Sn Phases Observed at Great Distances in the Western Pacific

DANIEL A. WALKER 1, CHARLES S. MCCREERY 1, GEORGE H. SUTTON 1, and FREDERICK K. DUENNEBIER 1

1 Hawaii Institute of Geophysics, University of Hawaii, Honolulu 96822

Both Pn, and Sn, phases recorded at distances greater than 3000 kilometers in the western Pacific have substantial amounts of energy at high frequencies, in sorne instances as high as 12 hertz for Pn and 15 hertz for Sn, A comparison of Pn and Sn spectra reveals generally higher energy levels and higher proportions of high-frequency to low-frequency energy for Sn than for Pn. Estimates of the effective quality factor, Q, indicate that the efficiency of Sn propagation may be two or three times that of Pn. First arrivals of Pn and Sn have apparent velocities in agreement with values for the uppermost mantle, whereas maximum-energy arrivals have apparent velocities in agreement with values for the lower crust.

Submitted on October 12, 1977


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
T-phase spectra, seismic moments, and tsunamigenesis.
D. A. WALKER, C. S. MCCREERY, and Y. HIYOSHI (1992)
Bulletin of the Seismological Society of America 82, 1275-1305
   Abstract »    PDF »
Wave train characteristics of long-range, high-frequency Pn,Sn crossing an ocean bottom hydrophone array.
C. S. MCCREERY and G. H. SUTTON (1980)
Bulletin of the Seismological Society of America 70, 437-446
   Abstract »    PDF »


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