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TitleCharacteristics of the 17 May 2013 M4.5 Ladysmith, Quebec, earthquake
AuthorAtkinson, G M; Assatourians, K; Lamontagne, M
SourceSeismological Research Letters vol. 85, no. 3, 2014 p. 755-762, https://doi.org/10.1785/0220130160
Year2014
Alt SeriesEarth Sciences Sector, Contribution Series 20130472
PublisherSeismological Society of America
Documentserial
Lang.English
Mediapaper; on-line; digital
File formatpdf
ProvinceQuebec; Ontario; Eastern offshore region
NTS21E; 21L; 21M; 30L; 30M; 30N; 31; 40I; 40J; 40O; 40P; 41A; 41B; 41G; 41H; 41I; 41J; 41O; 41P
AreaLadysmith; United States
Lat/Long WENS -84.0000 -70.0000 48.0000 41.0000
Subjectstectonics; geophysics; earthquakes; seismic models; seismic data; Brune model spectrum; Ottawa-Bonnechere graben
Illustrationslocation maps; graphs
ProgramAssessing Earthquake Geohazards, Public Safety Geoscience
AbstractThe 17 May 2013 M 4.5 Ladysmith, Quebec, earthquake produced a rich instrumental and felt ground-motion database. We use instrument-corrected response spectra and Fourier amplitude data from 189 stations, at distances from 10 to 700 km, to examine the attenuation and source characteristics of this event. An interesting observation is that amplitudes were elevated throughout southern Ontario, probably due to site effects, possibly coupled with source radiation effects. Using attenuation-corrected observations, in combination with the known seismic moment to constrain the absolute amplitude level at the source, we obtain an apparent source spectrum for the Ladysmith earthquake. The Ladysmith source spectrum is well described by a Brune model spectrum for an event of M 4.5 with a stress drop of ~500 bars. Overall, the source and attenuation characteristics of the Ladysmith event were typical for regional events. The earthquake occurred within the boundaries of the Ottawa-Bonnechere graben, which suggests a reactivation of one of its faults, though it is unclear which fault was involved. The focal mechanism does not match the orientation of the most conspicuous lineaments of the area. The earthquake may have reactivated a northwest-southeast brittle fault of local extent or a ductile thrust fault of the Grenville Geological Province.
Summary(Plain Language Summary, not published)
The M4.5 May 17, 2013 Ladysmith, Quebec earthquake produced a rich instrumental and felt ground-motion database. Overall the source and attenuation characteristics of the Ladysmith event were 'typical' for regional events. The earthquake occurred within the boundaries of the Ottawa-Bonnechere Graben, which suggests a reactivation of one of its faults, though it is unclear which fault was involved.
GEOSCAN ID293689