| Title | The 2017 Barrow Strait, Arctic Canada, earthquake sequence and contemporaneous regional seismicity |
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| Author | Bent, A; Kolaj, M; Ackerley, N; Adams, J ; Halchuk, S |
| Source | Seismological Research Letters vol. 89, no. 5, 2018 p. 1977-1988, https://doi.org/10.1785/0220180100 |
| Image |  |
| Year | 2018 |
| Alt Series | Natural Resources Canada, Contribution Series 20190002 |
| Publisher | Seismological Society of America (SSA) |
| Document | serial |
| Lang. | English |
| Media | paper; on-line; digital |
| File format | pdf (Adobe® Reader®); html |
| Province | Nunavut; Northern offshore region |
| NTS | 58C/14; 58C/15; 58C/16; 58D/13; 58D/14; 58D/15; 58E/02; 58E/03; 58E/04; 58E/05; 58E/06; 58E/07; 58E/10; 58E/11; 58E/12; 58F/01; 58F/02; 58F/03; 58F/06; 58F/07; 58F/08 |
| Area | Barrow Strait; Resolute; Somerset Island; Cornwallis Island |
| Lat/Long WENS | -95.0000 -89.0000 74.7500 73.9167 |
| Subjects | geophysics; tectonics; seismology; earthquakes; seismicity; earthquake magnitudes; epicentres; aftershocks; earthquake mechanisms; bedrock geology; structural features; faults, thrust; grabens; tectonic
setting; stress analyses; rifts; seismic waves; attenuation; seismic risk; earthquake risk; 2017 Barrow Strait Earthquake |
| Illustrations | location maps; geoscientific sketch maps; plots; focal mechanisms; seismograms; tables; histograms |
| Program | Canadian Hazard Information Service |
| Released | 2018 08 01 |
| Abstract | On 8 January 2017 (23:47:11UTC), a moment magnitude (Mw) 5.9 earthquake occurred in the Barrow Strait, 93 km southeast of Resolute, Nunavut, in the Canadian Arctic. This earthquake was one of the
largest to occur in eastern Canada in the past 50 yrs. It was followed by 33 locatable aftershocks, two of which had an Mw greater than 5.0. Regional centroid moment tensor (RCMT) inversions for the mainshock and largest aftershocks are predominantly
indicative of thrust faulting in response to northeast- southwest compression. These solutions are consistent with the broader regional stress field and with the orientation of mapped rift faults on nearby Somerset Island, although we cannot
associate the Barrow Strait earthquakes with any specific fault. Moment tensor inversions and analyses of teleseismic depth phases all indicate that the main shock was a deep crustal event that occurred at a depth of approximately 33-35 km. The
aftershocks also appear to be deep, but their depths are not well constrained. The Barrow Strait mainshock was reported to have been felt in several communities, a rarity in the Arctic; this allowed us an opportunity to assess attenuation as a
function of distance. In comparison to the 1988 Saguenay earthquake that occurred in southeastern Canada, which was of a similar size and depth, the felt reports are consistently of lower intensity, suggesting higher attenuation in the Arctic. A
comparison of ground-motion prediction equations (GMPEs) to recorded signals also suggests higher attenuation of velocity in the Arctic. While the Barrow Strait aftershock sequence was ongoing, an Mw 4.7 earthquake occurred approximately 500 km
northwest of Resolute. Analysis of seismicity rates shows that these events occurred during a time period of enhanced seismic activity in the Arctic. Similar periods of high activity have been observed over the past few decades, but they appear to be
short-lived and not indicative of a long-term increase in seismic activity. |
| Summary | (Plain Language Summary, not published)
In January 2017, a magnitude 5.9 earthquake occurred in Barrow Strait southeast of Resolute, Nunavut. This was one of the largest earthquakes to occur
in eastern Canada in the last 50 years. The earthquake and several large aftershocks were well recorded by the Canadian National Seismograph Network. The mainshock was felt in several communities in the Arctic. Analysis of the recorded waveforms
shows that the earthquakes were thrust faulting events that occurred near the base of the crust. While the earthquakes cannot be associated with a specific fault, the orientation of the fault planes derived from modeling are consistent with mapped
faults. Analysis of felt reports and ground motion data suggests that the shaking levels were lower than would be expected from a comparable earthquake in southern Canada. These earthquakes occurred during a period of enhanced seismic activity in
the Arctic. Similar periods of increased activity have been noted in the past but the cause is not certain. |
| GEOSCAN ID | 314585 |
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