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TitleReactivation of an intraplate fault by mine-blasting events: implications to regional seismic hazard in Western Canada
 
AuthorDokht, R M H; Smith, B; Kao, HORCID logo; Visser, R; Hutchinson, J
SourceJournal of Geophysical Research, Solid Earth vol. 125, no. 6, 2020 p. 1-16, https://doi.org/10.1029/2020JB019933
Image
Year2020
Alt SeriesNatural Resources Canada, Contribution Series 20200031
PublisherAmerican Geophysical Union
Documentserial
Lang.English
Mediapaper; on-line; digital
File formatpdf; html
ProvinceAlberta; British Columbia
NTS93J; 93K/01; 93K/02; 93K/08; 93K/09; 93K/10; 93K/15; 93K/16; 93N/01; 93N/02; 93N/07; 93N/08; 93O/01; 93O/02; 93O/03; 93O/04; 93O/05; 93O/06; 93O/07; 93O/08
AreaFort St. James; Prince George; Mackenize
Lat/Long WENS-125.0000 -122.0000 55.5000 54.0000
Subjectsgeophysics; structural geology; Science and Technology; Nature and Environment; Health and Safety; Economics and Industry; seismology; seismicity; seismic risk; earthquakes; earthquake risk; mining activities; bedrock geology; structural features; faults; trend surface analyses; strain analysis; Rocky Mountain Trench; Mount Milligan Mine; Brule Coal Mine; Willow Creek Mine; Canadian Cordillera; Quesnel Terrane; Ancestral North America Terrane; Cassiar Terrane; Slide Mountain Terrane; Cahe Creek Terrane; Manson-McLeod Fault System; Swannell Thrust Fault; Pinchi Fault; Pundata Thrust
Illustrationslocation maps; geoscientific sketch maps; histograms; flow diagrams; plots; cross-sections; tables
ProgramEnvironmental Geoscience Shale Gas - induced seismicity
Released2020 05 19
AbstractMining activities are well known for being able to induce local seismicity but have not yet been shown to cause earthquakes over a large distance (> 20 km). We analyze a particular group of seismic events recorded from 2014 to 2016 in north-central British Columbia (BC) that appear to be triggered by the activities at the Mount Milligan mine. The spatial distribution of the studied events follows a NW-SE linear trend, with distances up to approximately 100 km from the mining site. To distinguish mining blasts from blasting-related and natural events, we adopt a multivariate decision tree based on each events origin time, distance from the mine, and the pseudo-spectral acceleration ratios of the three-component waveforms. The calculated dynamic strain from blasts at various distance ranges along with the estimated earthquake location errors support the existence of blasting-triggered events at large distances (up to ~50 km) from the mine, suggesting that a previously unmapped fault segment is close to critical state and may have been reactivated. The inferred fault segment aligns remarkably well with the southern extent of the Rocky Mountain Trench and may impose a significant hazard to nearby communities if the entire fault segment of about 150 km-long ruptures.
Summary(Plain Language Summary, not published)
Mining activities are well known for being able to induce local seismicity but have not yet been shown to cause earthquakes over a large distance. We analyze a particular group of seismic events recorded from 2014 to 2016 in north-central British Columbia (BC) that appear to be triggered by the activities at the Mount Milligan mine. The spatial distribution of the studied events follows a NW-SE linear trend, with distances up to approximately 100 km from the mining site. The induced seismicity suggests that a previously unmapped fault segment may have been reactivated. This fault segment may impose a significant hazard to nearby communities if the entire length of about 150 km-long ruptures.
GEOSCAN ID325462

 
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