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TitreCoda Q in southwestern British Columbia, Canada
AuteurZelt, B C; Dotzev, N T; Ellis, R M; Rogers, G C
SourceBulletin of the Seismological Society of America vol. 89, no. 4, 1999 p. 1083-1093
LiensAbstract - Résumé
Année1999
Séries alt.Commission géologique du Canada, Contributions aux publications extérieures 1998274
Documentpublication en série
Lang.anglais
Mediapapier
ProvinceColombie-Britannique
SNRC92B; 92C; 92E; 92F; 92G; 92H; 92I; 92J; 92K; 92L
Lat/Long OENS-128.0000 -120.0000 51.0000 47.0000
Sujetsprospection sismique; données sismiques; méthodes sismiques; réseau de mesure; interpretations sismiques; énergie sismique; cadre tectonique; sismicité; géophysique; géomathématique
Illustrationslocation maps; cross-sections, structural; graphs; tables; contour maps
ProgrammeCRSNG Conseil de recherches en sciences naturelles et en génie du Canada
Résumé(disponible en anglais seulement)
Coda decay rates of 122 locally recorded earthquakes are used to infer frequency-dependent coda Q values at 21 short-period stations in southwestern British Columbia, Canada. Using the single-scattering model, coda Q values (Qc) are derived for a range of sampling volumes corresponding to maximum lapse times of 36-59 sec and maximum sampling depths of 70-110 km. Maps of Q0 (Qc inferred at 1 Hz) for different sampling volumes show a consistent trend of increasing Q0 to the northeast away from the subduction zone and into the Coast Belt batholith, and decreasing Q0 toward the southeastern-most stations near the Vedder fault at the southern terminus of the Coast Belt. Q0 increases gradually with sampling volume at all stations. The dependence of Qc on frequencies between 2 and 16 Hz for different stations varies but on average ranges from 280 at 2 Hz to 850 at 16 Hz for sampling volumes that extend to depths of ~90 km. An average of all data for the same sampling volume size gives a relationship of Qc = 110 f0.72 for frequencies in the 2- to 16-Hz range, which suggests significant differences in lithospheric coda attenuation properties in comparison with northwestern Washington State where Qc = 63 f0.97. Changes in coda Q correlate with the volume of brittle and fractured continental and subducting oceanic lithosphere sampled.
GEOSCAN ID210306