|
|
||||||||
SEISMOGRAPHIC STATION UNIVERSITY OF CALIFORNIA, BERKELEY, CALIFORNIA
Abstract
The spectra of the Love waves from five earthquakes of the 1966 Parkfield sequence, recorded at Berkeley, have been studied for evidence of source propagation. Independent field evidence suggests that the source of the main shock of the sequence may have propagated on a line away from Berkeley. The modulation effect of propagation on the amplitude spectrum is discussed. This effect is dependent upon the total time delay due to rupture down the fault and seismic wave propagation back to the point of initial rupture, and is thus ambiguous with respect to fault rupture velocity and fault length. Consideration of a frequency dependent phase velocity can resolve this ambiguity. The amplitude spectrum of the largest (M = 5.5) Parkfield earthquake shows sharp minima at periods where the spectra of the other four shocks are relatively smooth. Considered individually, these minima are consistent with a fault rupture length of about 30 km and a rupture velocity of 2.2 km/sec. The pattern of the minima varies from that predicted by the assumed phase velocities, thus the rupture velocity/fault length ambiguity is not resolved. Similarity in the shape of the spectra of the four smaller (M = 3.8-5.1) events suggests similar focal dimensions for these earthquakes. The Love wave amplitude spectra of the four smaller earthquakes scale well, at intermediate periods, to the magnitudes determined on standard short-period intruments; the main shock scales to a much higher magnitude. The spectra are considered in the light of proposed seismic scaling laws.
This article has been cited by other articles:
![]() |
W. H. BAKUN and T. V. MCEVILLY P-wave spectra for ML 5 foreshocks, aftershocks, and isolated earthquakes near Parkfield, California Bulletin of the Seismological Society of America, April 1, 1981; 71(2): 423 - 436. [Abstract] [PDF] |
||||
![]() |
H. S. HASEGAWA, J. C. LAHR, and C. D. STEPHENS Fault parameters of the St. Elias, Alaska, earthquake of February 28, 1979 Bulletin of the Seismological Society of America, October 1, 1980; 70(5): 1651 - 1660. [Abstract] [PDF] |
||||
![]() |
W. H. Bakun, W. H. BAKUN, and T. V. MCEVILLY Earthquakes near Parkfield, California: Comparing the 1934 and 1966 Sequences Science, September 28, 1979; 205(4413): 1375 - 1377. [Abstract] [PDF] |
||||
![]() |
M. D. TRIFUNAC and F. E. UDWADIA Parkfield, California, earthquake of June 27, 1966: A three-dimensional moving dislocation Bulletin of the Seismological Society of America, June 1, 1974; 64(3-1): 511 - 533. [Abstract] [PDF] |
||||
![]() |
J. ANDERSON A dislocation model for the Parkfield earthquake Bulletin of the Seismological Society of America, June 1, 1974; 64(3-1): 671 - 686. [Abstract] [PDF] |
||||
![]() |
P. MOLNAR, B. E. TUCKER, and J. N. BRUNE Corner frequencies of P and S waves and models of earthquake sources Bulletin of the Seismological Society of America, December 1, 1973; 63(6-1): 2091 - 2104. [Abstract] [PDF] |
||||
![]() |
S. J. GIBOWICZ Stress drop and aftershocks Bulletin of the Seismological Society of America, August 1, 1973; 63(4): 1433 - 1446. [Abstract] [PDF] |
||||
![]() |
A. NIAZY Elastic displacements caused by a propagating crack in an infinite medium: An exact solution Bulletin of the Seismological Society of America, April 1, 1973; 63(2): 357 - 379. [Abstract] [PDF] |
||||
![]() |
R. C. LIEBERMANN and P. W. POMEROY Source dimensions of small earthquakes as determined from the size of the aftershock zone Bulletin of the Seismological Society of America, June 1, 1970; 60(3): 879 - 890. [Abstract] [PDF] |
||||
![]() |
M. NIAZI Source dynamics of the Dasht-e Bayaz earthquake of August 31, 1968 Bulletin of the Seismological Society of America, October 1, 1969; 59(5): 1843 - 1861. [Abstract] [PDF] |
||||
![]() |
Y.-B. TSAI and K. AKI Simultaneous determination of the seismic moment and attenuation of seismic surface waves Bulletin of the Seismological Society of America, February 1, 1969; 59(1): 275 - 287. [Abstract] [PDF] |
||||
![]() |
T. V. MCEVILLY, W. H. BAKUN, and K. B. CASADAY The Parkfield, California, earthquakes of 1966 Bulletin of the Seismological Society of America, December 1, 1967; 57(6): 1221 - 1244. [Abstract] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |