| Title | Ground-motion characteristics of the 30 November 2018 injection-induced earthquake sequence in northeast British Columbia, Canada |
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| Author | Babaie Mahani, A; Kao, H ; Atkinson, G M; Assatourians, K; Addo, K; Liu, Y |
| Source | Seismological Research Letters vol. 90, no. 4, 2019 p. 1457-1467, https://doi.org/10.1785/0220190040 |
| Image |  |
| Year | 2019 |
| Alt Series | Natural Resources Canada, Contribution Series 20190073 |
| Publisher | Seismological Society of America (SSA) |
| Document | serial |
| Lang. | English |
| Media | paper; on-line; digital |
| File format | pdf (Adobe® Reader®); html |
| Province | British Columbia; Alberta |
| NTS | 83D; 83E; 83K; 83L; 83M; 83N; 84C; 84D; 84E; 84L; 93G; 93H; 93I; 93J; 93O; 93P; 94A; 94B; 94G; 94H; 94I; 94J |
| Area | Septimus; Fort St. John; Dawson Creek; Fort Nelson; Grand Prairie; Peace River |
| Lat/Long WENS | -123.0000 -116.0000 59.0000 53.0000 |
| Subjects | geophysics; fossil fuels; Science and Technology; petroleum industry; hydrocarbon recovery; hydraulic fracturing; seismology; earthquakes; seismic risk; dams; seismic waves; earthquake magnitudes;
models; array seismology; seismological network; Site C Dam; Canadian Cordillera; Infrastructures |
| Illustrations | tables; location maps; focal mechanisms; plots; time series |
| Program | Environmental Geoscience Shale Gas - induced seismicity |
| Released | 2019 06 19 |
| Abstract | On 30 November 2018, three felt earthquakes occurred in the Septimus region of northeast British Columbia in an area where hydraulic fracturing was in progress. The proximity of oil and gas activities
to populated areas and to critical infrastructure including major dams raises significant concern regarding the seismic hazard posed by moderate induced events and motivates study of their ground motions. Here, we analyze the ground-motion amplitudes
from these events recorded between 3 and 400 km. We use three-component waveforms from 45 seismometer and accelerometer sensors to analyze the observed ground motions. The moment magnitude (Mw) of the first event is estimated as 4.6 using the
vertical pseudoresponse spectral acceleration (PSA) based on the relations provided by Novakovic et al. (2018). The Mw for the two smaller earthquakes are 3.5 and 4.0. The intensity of shaking from the Mw 4.6 and 4.0 events generally exceeded
modified Mercalli intensity (MMI) VI at distances <6 km. The maximum duration above the MMI VI threshold at the closest station (3.5 km distance) from the mainshock is 1.6 s. The observed ground motions agree with the ground-motion prediction
equation (GMPE) of Novakovic et al. (2018) for induced events in Oklahoma, with attenuation modified to match that for the study region, assuming typical regional site amplification. The inferred value of stress drop for the mainshock and the largest
aftershock is approximately 50 bars based on the agreement of observed PSA values with the Novakovic et al. (2018) GMPE. |
| Summary | (Plain Language Summary, not published)
This study investigates the ground motion characteristics associated with the Nov 30, 2018, injection-induced earthquake sequence in northeast British
Columbia. The mainshock had a magnitude of 4.6, and the two largest aftershocks are M 3.5 and 4.0, respectively. The largest shaking was observed at distances less than 6 km from the epicenter. The duration of the strong shaking is 1.6 s. The
observed ground motions agree with theoretical model predictions. |
| GEOSCAN ID | 314701 |
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