| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
GEOPHYSICS DIVISION DEPARTMENT OF PHYSICS UNIVERSITY OF TORONTO, TORONTO, ONTARIO, Canada, M5B 1A7
Abstract
Spectral amplitudes of regionally recorded Lg waves are studied in detail between 0.6 and 10 Hz, using vertical-component, velocity seismograms of the Eastern Canada Telemetered Network stations and a supplementary Seismic Research Observatory-type station at Glen Almond (GAC), Québec. We find that the site responses vary among these stations by more than a factor of 3 within the frequency range of interest. Furthermore, they are found to be strongly frequency dependent. Consequently, it is essential that they be taken into consideration in studies of Lg wave attenuation and Lg source spectra of regionally recorded seismic events.
We present a new method of measuring interstation surface wave attenuation, which is closely related to the conventional two-station method. While retaining all the desirable features of the conventional two-station method, the new technique, which we will call the "reversed two-station method," allows simple, direct (one-parameter) determination of the Lg wave attenuation from sparse spectral data in a manner unaffected by station site effects and associated instrument error.
The reversed two-station method is successfully tested over weakly attenuating, short (53 to 210 km) interstation paths in eastern Canada, a difficult experimental condition by normal standards. The Lg attenuation coefficient (0.6 to 10 Hz) in eastern Canada is found to be frequency dependent and of the form 
(f) = 0.0008 f0.81 km–1. At higher frequencies, the Lg attenuation appears to be essentially frequency independent. This latter finding is preliminarily interpreted as evidence that regionally recorded Lg waves in the Canadian Shield are, as in the case of Lg waves propagating through the structurally complex Appalachian Province, contaminated by the high-frequency coda of Sn waves. The Lg contamination over the shield paths becomes severe starting at 14 Hz, twice the frequency above which the Lg signal propagating over the Appalachian Province becomes completely dominated by non-Lg arrivals.
This article has been cited by other articles:
|
|
 |
|
  P. Morasca, K. Mayeda, R. Gok, W. S. Phillips, and L. Malagnini 2D Coda and Direct-Wave Attenuation Tomography in Northern Italy Bulletin of the Seismological Society of America, August 1, 2008; 98(4): 1936 - 1946. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. R. Ford, D. S. Dreger, K. Mayeda, W. R. Walter, L. Malagnini, and W. S. Phillips Regional Attenuation in Northern California: A Comparison of Five 1D Q Methods Bulletin of the Seismological Society of America, August 1, 2008; 98(4): 2033 - 2046. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. W. Chung, M.-H. Noh, J.-K. Kim, Y.-K. Park, H.-J. Yoo, and J. M. Lees A Study of the Regional Variation of Low-Frequency around the Korean Peninsula Bulletin of the Seismological Society of America, December 1, 2007; 97(6): 2190 - 2197. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. Sonley and G. M. Atkinson Path-Specific Attenuation in Eastern Canada Bulletin of the Seismological Society of America, August 1, 2006; 96(4A): 1375 - 1382. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. Cramer An Assessment of the Impact of the 2003 EPRI Ground-Motion Prediction Models on the USGS National Seismic-Hazard Maps Bulletin of the Seismological Society of America, June 1, 2006; 96(3): 1159 - 1169. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. W. Chung, Y. K. Park, I. B. Kang, and K. Lee Crustal in South Korea Using the Source Pair/Receiver Pair Method Bulletin of the Seismological Society of America, April 1, 2005; 95(2): 512 - 520. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Q of the Indian Shield Bulletin of the Seismological Society of America, August 1, 2004; 94(4): 1564 - 1570.
|
|
|
|
|
|
Empirical Attenuation of Ground-Motion Spectral Amplitudes in Southeastern Canada and the Northeastern United States Bulletin of the Seismological Society of America, June 1, 2004; 94(3): 1079 - 1095.
|
|
|
|
|
|
Strong Lg Attenuation in the Tibetan Plateau Bulletin of the Seismological Society of America, October 1, 2003; 93(5): 2264 - 2272.
|
|
|
|
|
|
Estimation of Q-Values in the Seismogenic and Aseismic Layers in the Kinki Region, Japan, by Elimination of the Geometrical Spreading Effect Using Ray Approximation Bulletin of the Seismological Society of America, August 1, 2003; 93(4): 1498 - 1515.
|
|
|
|
|
|
Attenuation of High-Frequency P and S Waves in the Crust of Southeastern South Korea Bulletin of the Seismological Society of America, December 1, 2001; 91(6): 1867 - 1874.
|
|
|
|
|
|
S. K. Singh, M. Ordaz, R. S. Dattatrayam, and H. K. Gupta A spectral analysis of the 21 May 1997, Jabalpur, India, earthquake (Mw = 5.8) and estimation of ground motion from future earthquakes in the Indian shield region Bulletin of the Seismological Society of America, December 1, 1999; 89(6): 1620 - 1630. [Abstract] [PDF]
|
|
|
|
|
|
H. M. Benz, A. Frankel, and D. M. Boore Regional Lg attenuation for the continental United States Bulletin of the Seismological Society of America, June 1, 1997; 87(3): 606 - 619. [Abstract] [PDF]
|
|
|
|
|
|
T.-R. Zhang, T. Lay, S. Schwartz, and W. R. Walter Variation of regional seismic discriminants with surface topographic roughness in the Western United States Bulletin of the Seismological Society of America, June 1, 1996; 86(3): 714 - 725. [Abstract] [PDF]
|
|
|
|
|
|
A. Frankel Implications of felt area-magnitude relations for earthquake scaling and the average frequency of perceptible ground motion Bulletin of the Seismological Society of America, April 1, 1994; 84(2): 462 - 465. [Abstract] [PDF]
|
|
|
|
|
|
G. M. ATKINSON and R. F. MEREU The shape of ground motion attenuation curves in southeastern Canada Bulletin of the Seismological Society of America, October 1, 1992; 82(5): 2014 - 2031. [Abstract] [PDF]
|
|
|
|
|
|
T. ZHU, K.-Y. CHUN, and G. F. WEST Geometrical spreading and Q of Pn waves: An investigative study in eastern Canada Bulletin of the Seismological Society of America, June 1, 1991; 81(3): 882 - 896. [Abstract] [PDF]
|
|
|
|
|
|
J. ROGER BOWMAN and B. L. N. KENNETT Propagation of Lg waves in the North Australian Craton: Influence of crustal velocity gradients Bulletin of the Seismological Society of America, April 1, 1991; 81(2): 592 - 610. [Abstract] [PDF]
|
|
|
|
|
|
T. J. SERENO Jr. Frequency-dependent attenuation in eastern Kazakhstan and implications for seismic detection thresholds in the Soviet Union Bulletin of the Seismological Society of America, December 1, 1990; 80(6B): 2089 - 2105. [Abstract] [PDF]
|
|
|
|
|
|
C. R. D. WOODGOLD Estimation of Q in eastern Canada using coda waves Bulletin of the Seismological Society of America, April 1, 1990; 80(2): 411 - 429. [Abstract] [PDF]
|
|
|
|
|
|
K.-Y. CHUN, R. J. KOKOSKI, and G. F. WEST High-frequency Pn attenuation in the Canadian shield Bulletin of the Seismological Society of America, August 1, 1989; 79(4): 1039 - 1053. [Abstract] [PDF]
|
|
|
|
|
|
T. ZHU, K.-Y. CHUN, and G. F. WEST High-frequency P-wave attenuation determination using multiple-window spectral analysis method Bulletin of the Seismological Society of America, August 1, 1989; 79(4): 1054 - 1069. [Abstract] [PDF]
|
|
|
|
|
|
K.-Y. CHUN, R. J. KOKOSKI, and G. F. WEST Source spectral characteristics of Miramichi earthquakes: Results from 115 P-wave observations Bulletin of the Seismological Society of America, February 1, 1989; 79(1): 15 - 30. [Abstract] [PDF]
|
|
|
|
|
|
K.-Y. CHUN, R. J. KOKOSKI, and G. F. WEST Network calibration for Lg magnitude--method and test results from eastern Canada Bulletin of the Seismological Society of America, February 1, 1989; 79(1): 127 - 140. [Abstract] [PDF]
|
|
|
|
|
|
R. K. MCGUIRE Introduction Bulletin of the Seismological Society of America, April 1, 1987; 77(2): 319 - 321. [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
