Bulletin of the Seismological Society of America
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Bulletin of the Seismological Society of America; February 1964; v. 54; no. 1; p. 191-208
© 1964 Seismological Society of America
This Article
Right arrow Full Text (PDF)
Right arrow References
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by BOLT, B. A.
Right arrow Search for Related Content
GeoRef
Right arrow GeoRef Citation

The velocity of seismic waves near the earth's center

BRUCE A. BOLT

SEISMOGRAPH STATION UNIVERSITY OF CALIFORNIA, BERKELEY, CALIFORNIA

Abstract

A double velocity jump in the Earth's core entails a PKP travel-time curve with two lengthy branches extending back from 143°. The later branch is associated with the PKIKP phase. The earlier branch arises from waves, here designated PKHKP, which are refracted through the intermediate shell.

Theoretical travel-time curves for PKP and SKS in possible Earth models with tripartite cores are presented. It is shown that the PKHKP branch provides an explanation for precursors to PKIKP observed at epicentral distances between 123° and 140°. Observations of waves predicted by the portion of this branch from 148° to 156° have been also reported. The SKS curve is examined in the light of some 550 SKS observations in the range 85° < {Delta} < 145°.

The study provides evidence that there is in the core a discrete shell with thickness of order 420 kms and with a mean P velocity near 10.31 km/sec. This shell surrounds the inner core having mean radius 1220 kms and mean P velocity 11.22 km/sec, approximately. The material of the intermediate shell is not likely to have marked rigidity. The inner core is likely to be solid; published times for PKJKP waves may be, however, too small by several minutes.




This article has been cited by other articles:


Home page
 Bulletin of the Seismological Society of AmericaHome page
J. Schlittenhardt
Array analysis of core-phase caustic signals from underground nuclear explosions: Discrimination of closely spaced explosions
Bulletin of the Seismological Society of America, February 1, 1996; 86(1A): 159 - 171.
[Abstract] [PDF]

Home page
 Bulletin of the Seismological Society of AmericaHome page
A. C. CHANG and J. R. CLEARY
Precursors to PKKP
Bulletin of the Seismological Society of America, August 1, 1978; 68(4): 1059 - 1079.
[Abstract] [PDF]

Home page
 Bulletin of the Seismological Society of AmericaHome page
B. A. BOLT
Abnormal seismology
Bulletin of the Seismological Society of America, April 1, 1976; 66(2): 617 - 623.
[PDF]

Home page
 Bulletin of the Seismological Society of AmericaHome page
C. WRIGHT
The origin of short-period precursors to PKP
Bulletin of the Seismological Society of America, June 1, 1975; 65(3): 765 - 786.
[Abstract] [PDF]

Home page
 Bulletin of the Seismological Society of AmericaHome page
G. G. R. BUCHBINDER, C. WRIGHT, and G. POUPINET
Observations of PKiKP at distances less than 110{degrees}
Bulletin of the Seismological Society of America, October 1, 1973; 63(5): 1699 - 1707.
[Abstract] [PDF]

Home page
 Bulletin of the Seismological Society of AmericaHome page
R. DATT and T. G. VARGHESE
Array detection and location of core shadow events
Bulletin of the Seismological Society of America, February 1, 1972; 62(1): 231 - 245.
[Abstract] [PDF]

Home page
 Bulletin of the Seismological Society of AmericaHome page
G. G. R. BUCHBINDER
A velocity structure of the Earth's core
Bulletin of the Seismological Society of America, April 1, 1971; 61(2): 429 - 456.
[Abstract] [PDF]

Home page
 Bulletin of the Seismological Society of AmericaHome page
E. HUSEBYE and R. MADARIAGA
The origin of precursors to core waves
Bulletin of the Seismological Society of America, June 1, 1970; 60(3): 939 - 952.
[Abstract] [PDF]

Home page
 Bulletin of the Seismological Society of AmericaHome page
B. A. BOLT
Estimation of PKP travel times
Bulletin of the Seismological Society of America, August 1, 1968; 58(4): 1305 - 1324.
[Abstract] [PDF]

Home page
 Bulletin of the Seismological Society of AmericaHome page
D. H. SHURBET
The earthquake P phases which penetrate the earth's core
Bulletin of the Seismological Society of America, October 1, 1967; 57(5): 875 - 890.
[Abstract] [PDF]

Home page
 Bulletin of the Seismological Society of AmericaHome page
J. S. DERR
A comparison of free oscillations of oceanic and continental earth models
Bulletin of the Seismological Society of America, October 1, 1967; 57(5): 1047 - 1061.
[Abstract] [PDF]

Home page
 Bulletin of the Seismological Society of AmericaHome page
A. A. NOWROOZI
Terrestrial spectroscopy following the Rat Island earthquake
Bulletin of the Seismological Society of America, December 1, 1966; 56(6): 1269 - 1288.
[Abstract] [PDF]

Home page
 Bulletin of the Seismological Society of AmericaHome page
W. J. HANNON and R. L. KOVACH
Velocity filtering of seismic core phases
Bulletin of the Seismological Society of America, April 1, 1966; 56(2): 441 - 454.
[Abstract] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 1964 by the Seismological Society of America.