HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Full Text (PDF) Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (3) Citing Articles via Google Scholar Google Scholar Articles by Macias, M. Articles by Motazedian, D. Search for Related Content GeoRef GeoRef Citation

Ground-Motion Attenuation, Source, and Site Effects for the 26 September 2003 M 8.1 Tokachi-Oki Earthquake Sequence

Department of Earth Sciences, Carleton University, Ottawa, Ontario K1S5B6, Canada

Gail M. Atkinson

Department of Earth Sciences, University of Western Ontario, London, Ontario N6A 5B6, Canada

Dariush Motazedian

Department of Earth Sciences, Carleton University, Ottawa, Ontario K1S5B6, Canada

On 26 September 2003 a megathrust earthquake of M 8.1 occurred at the Kurile trench, Northern Japan. We used accelerograms recorded on more than 300 K-NET stations, ranging in distance from 40 to 500 km, to determine source, attenuation, and site effects for the mainshock and four aftershocks with M 7.3, 6.4, 5.9, and 5.5. The analyses are based on linear regression applied to the Fourier spectra data of each event.

The ground-motion attenuation for all the events can be modeled using an assumed geometric spreading coefficient b₁=-1.0 with an associated anelastic attenuation model given by an apparent Q=135f^0.76. By using dummy variables in the regression, site amplifications relative to National Earthquake Hazard Reduction Program (NEHRP) C sites are determined for D and E sites. Nonlinear site amplification was investigated for the M 8.1 data but was not significant in determining the overall amplification factors. Fourier spectra data were corrected to a reference near-source distance and site condition (hard rock). The source spectrum for each event was compared to that of the theoretical Brune-model spectrum, in order to compute seismic moment and stress drop. Seismic moments obtained in this manner agree with those of other studies. Stress drops range from 100 to 200 bars with no apparent dependence on magnitude. The mainshock stress drop was 120 bars. A similar value (100 bars) was calculated for an interface aftershock. Events with the highest stress drops (near 200 bars) may have been in-slab events.

This article has been cited by other articles:

				G. M. Atkinson and M. Macias Predicted Ground Motions for Great Interface Earthquakes in the Cascadia Subduction Zone Bulletin of the Seismological Society of America, June 1, 2009; 99(3): 1552 - 1578. [Abstract] [Full Text] [PDF]

				A. A. Skarlatoudis, C. B. Papazachos, B. N. Margaris, Ch. Papaioannou, Ch. Ventouzi, D. Vamvakaris, A. Bruestle, T. Meier, W. Friederich, G. Stavrakakis, et al. Combination of Acceleration-Sensor and Broadband Velocity-Sensor Recordings for Attenuation Studies: The Case of the 8 January 2006 Kythera Intermediate-Depth Earthquake Bulletin of the Seismological Society of America, April 1, 2009; 99(2A): 694 - 704. [Abstract] [Full Text] [PDF]

				G. M. Atkinson and D. M. Boore Erratum to Empirical Ground-Motion Relations for Subduction Zone Earthquakes and Their Application to Cascadia and Other Regions Bulletin of the Seismological Society of America, October 1, 2008; 98(5): 2567 - 2569. [Full Text] [PDF]