| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
SEISMOLOGICAL LABORATORY CALIFORNIA INSTITUTE OF TECHNOLOGY, PASADENA, CALIFORNIA 91109
Abstract
The southeastern Missouri earthquake of October 21, 1965 generated fundamental- and higher-mode Love and Rayleigh waves which were recorded at numerous North American stations. Love-wave amplitude radiation patterns were determined and found to be consistent with theoretical patterns predicted by a fault-plane solution previously inferred from Rayleigh-wave data.
The radiation patterns were used to estimate the source spectrum and values for Love-wave attenuation coefficients for the mid-continent of North America by a least-squares iterative process. The source spectrum derived from Love-wave amplitudes exhibits a peak at periods between 5 and 9 sec and decreases to a lower DC level at longer periods, in agreement with the source spectrum determined previously for Rayleigh waves. The Love-wave attenuation coefficients decrease rapidly from about 0.0018 km–1 at a period of 4 sec to about 0.0001 km–1 at a period of 20 sec. At periods between 20 and 40 sec the values seem to remain nearly constant.
The crust in the mid-continent of North America is characterized by relatively low Qß values, 75 to 300, in its upper portion. At depths between 15 and 20 km, Qß increases sharply and decreases again at greater depths. The decrease can be explained as being due to increasing temperature in a homogeneous material, but the sharp increase requires a change in the chemical constitution of the material at mid-crustal depths.
This article has been cited by other articles:
|
|
 |
|
  T. S. YELIN and H. J. PATTON Seismotectonics of the Portland, Oregon, region Bulletin of the Seismological Society of America, February 1, 1991; 81(1): 109 - 130. [Abstract] [PDF]
|
|
|
|
|
|
P. W. POMEROY, W. J. BEST, and T. V. MCEVILLY Test ban treaty verification with regional data--A review Bulletin of the Seismological Society of America, December 1, 1982; 72(6B): S89 - S129. [Abstract] [PDF]
|
|
|
|
|
|
C.-C. CHENG and B. J. MITCHELL Crustal Q structure in the United States from multi-mode surface waves Bulletin of the Seismological Society of America, February 1, 1981; 71(1): 161 - 181. [Abstract] [PDF]
|
|
|
|
|
|
B. J. MITCHELL and R. B. HERRMANN Shear velocity structure in the Eastern United States from the inversion of surface-wave group and phase velocities Bulletin of the Seismological Society of America, August 1, 1979; 69(4): 1133 - 1148. [Abstract] [PDF]
|
|
|
|
|
|
N. K. YACOUB and B. J. MITCHELL Attenuation of Rayleigh-wave amplitudes across Eurasia Bulletin of the Seismological Society of America, June 1, 1977; 67(3): 751 - 769. [Abstract] [PDF]
|
|
|
|
|
|
R. B. HERRMANN and B. J. MITCHELL Statistical analysis and interpretation of surface-wave anelastic attenuation data for the stable interior of North America Bulletin of the Seismological Society of America, October 1, 1975; 65(5): 1115 - 1128. [Abstract] [PDF]
|
|
|
|
|
|
L. W. BRAILE and G. R. KELLER Fine structure of the crust inferred from linear inversion of Rayleigh-wave dispersion Bulletin of the Seismological Society of America, February 1, 1975; 65(1): 71 - 83. [Abstract] [PDF]
|
|
|
|
|
|
R. M. HOUSLEY, B. R. TITTMANN, and E. H. CIRLIN Crustal porosity information from internal friction profile Bulletin of the Seismological Society of America, December 1, 1974; 64(6): 2003 - 2004. [PDF]
|
|
|
|
|
|
R. B. HERRMANN Surface-wave generation by the south central Illinois earthquake of November 9, 1968 Bulletin of the Seismological Society of America, December 1, 1973; 63(6-1): 2121 - 2134. [Abstract] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
