GEOSCAN, résultats de la recherche


TitreEstimating seismic moment magnitude (Mw) of tremor bursts in northern Cascadia: implications for the "seismic efficiency" of episodic tremor and slip
AuteurKao, H; Wang, K; Dragert, H; Kao, J Y; Rogers, G
SourceGeophysical Research Letters vol. 37, L19306, 2010, 6 pages,
Séries alt.Secteur des sciences de la Terre, Contribution externe 20100169
Documentpublication en série
Mediapapier; en ligne; numérique
ProvinceRégion extracotière de l'ouest; Colombie-Britannique
SNRC92A; 92B; 92E; 92F; 92K; 92L
Lat/Long OENS-128.0000 -122.0000 51.0000 48.0000
Sujetsinterpretations sismiques; risque sismique; zones sismiques; sismicité; levés sismiques; ondes sismiques; ondes transversales; géophysique
Illustrationslocation maps; profiles; plots; histograms
ProgrammeTargeted Hazard Assessments in Western Canada, Géoscience pour la sécurité publique
Résumé(disponible en anglais seulement)
We develop a method to estimate the seismic moments of deep non-volcanic tremor bursts observed in northern Cascadia. For each tremor burst, the maximum amplitudes at individual stations within a time window ±5 s around the predicted arrivals of the S phase are measured and compared to the maximum S amplitudes measured from synthetic seismograms. The proposed method is thoroughly
calibrated using 464 local earthquakes and the results show excellent consistency between the reported ML and the estimated Mw. We apply the method to northern Cascadia tremors and infer that most bursts have Mw~1.0-1.7. The corresponding b value appears to be 1, consistent with that of ordinary earthquakes but over a narrower Mw range. Comparison of cumulative tremor Mw and the Mw estimated from the accompanying slow slip suggests that the "seismic efficiency" of the Episodic Tremor and Slip (ETS) is of the order of 0.1% or less.