GEOSCAN, résultats de la recherche


TitreIdentifying active structures using double-difference earthquake relocations in southwest British Columbia and the San Juan Islands, Washington
AuteurBalfour, N J; Cassidy, J F; Dosso, S E
SourceBulletin of the Seismological Society of America vol. 102, no. 2, 2012 p. 639-649,
Séries alt.Secteur des sciences de la Terre, Contribution externe 20110032
Documentpublication en série
Mediapapier; en ligne; numérique
SNRC92G/01; 92G/02; 92G/07; 92G/08; 92G/09; 92G/10; 92H/04; 92H/05; 92H/12
Lat/Long OENS-123.0000 -121.7500 49.6667 48.7500
Lat/Long OENS-123.3333 -122.6667 48.8333 48.2500
Sujetssecousses séismiques; mécanismes de tremblement de terre; risque de tremblement de terre; études séismiques; séismologie; sismicité; géophysique
Illustrationslocation maps; plots
ProgrammeÉvaluations ciblées des dangers dans l'Ouest du Canada, Géoscience pour la sécurité publique
Diffusé2012 03 29
Résumé(disponible en anglais seulement)
This paper applies double-difference earthquake relocation techniques to investigate sources of seismicity in southwest British Columbia, Canada, and the San Juan Islands, Washington. The study area is a complex region of deformation and has the potential for large earthquakes in the North Americancrust. Double-difference earthquake relocation techniques are applied to identify otherwise-hidden active structures that may pose a hazard to nearby population and infrastructure. We present evidence for previously unrecognized active structures using precise relative earthquake relocations obtained using both catalog and waveform cross-correlation data. Results have significantly reduced errors over routine catalog locations and show lineations in areas of clustered seismicity. In southwest British Columbia, these lineations or streaks appear to be hidden structures that do not disrupt near-surface sediments; however, in the San Juan Islands the identified lineation could be related to recently mapped surface expressions of faults identified from seismic reflection and multibeam bathymetric surveys. We use a variety of velocity models for the relocations and find that inappropriate models lead to artifacts at layer boundaries and increased vertical errors.