2012 Haida Gwaii earthquake

Earthquake in Canada

2012 Haida Gwaii earthquake

UTC time| 2012-10-28 03:04:09
ISC event| 603860908
USGS-ANSS| ComCat
Local date| October 27, 2012 (2012-10-27)
Local time| 20:04:09 (PDT)
Duration| 90 seconds [1]
Magnitude| 7.8 Mw
Depth| 17.5 km (10.9 mi)
Epicenter| 52°46′08″N 131°55′37″W﻿ / ﻿52.769°N 131.927°W﻿ / 52.769; -131.927
Type| Thrust[1]
Areas affected| Canada
Max. intensity| MMI V (Moderate)[2]
Peak acceleration| 0.2 g[1]
Tsunami| Yes
Casualties| 1 dead (indirect)[3]

The 2012 Haida Gwaii earthquake occurred just after 8:04 p.m. PDT on October 27. The shock had a moment magnitude of 7.8 and a maximum Mercalli Intensity of V (Moderate). The earthquake's epicentre was on Moresby Island of the Haida Gwaii archipelago (formerly known as the Queen Charlotte Islands). This was the second largest Canadian earthquake ever recorded by a seismometer, after the 1949 Queen Charlotte Islands earthquake, about 135 kilometres (84 mi) away.[4] One person died due to a car crash related to the tsunami in Oahu, Hawaii.[3]

## Earthquake

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Strong shaking was felt throughout Haida Gwaii where residents in Masset, Skidegate, Sandspit, and Queen Charlotte City were evacuated to higher ground.[5] Minor shaking was felt in Prince Rupert and in other cities of the Interior such as Prince George, Quesnel, and as far away as Kamloops.[6] Electricity service was interrupted in Bella Coola.[7]

USGS ShakeMap for the event

Although the earthquake occurred on the Queen Charlotte Fault, a primarily strike-slip boundary between the Pacific and North American plates where the Pacific Plate moves approximately north-northwest with respect to the North America plate at a rate of about 50 mm/yr,[2] the 2012 quake exhibited a thrust mechanism, more characteristic of the Cascadia Subduction Zone to the south.[8]

## Tsunami

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A tsunami warning was issued for the North American Coast from the Alaskan Panhandle to Vancouver Island, but later limited to the North Coast region of British Columbia. Canadian authorities were questioned for issuing a tsunami warning nearly 40 minutes after the U.S. had issued their warning.[9] The greatest wave heights recorded at tide gauges in Canada were 25 cm (9.8 in) at Langara Island and 22 cm (8.7 in) at Winter Harbour.[10] In Tofino on Vancouver Island, the tsunami warning sirens were activated and residents in low-lying areas evacuated their homes.[7] The maximum wave height recorded in Tofino was 9 cm (3.5 in).[10] Tofino's tsunami warning system was activated after communication with the provincial coordinating centre was cut off.[11]

In the U.S., Hawaii was also placed on alert, and over 100,000[12] people were evacuated to higher ground. The maximum wave height recorded at tide gauges in Hawaii was 79 cm (31 in).[10] Other warnings were issued for the states of Oregon and California, but were subsequently lifted.[13] Along the western coast of Haida Gwaii, the earthquake triggered tsunami waves with a maximum run-up height at 13 meters in Davidson Inlet.[14] In Mike Inlet, the tsunami was measured at 7.6 meters, making it the largest tsunami generated by an earthquake in western Canadian history.[1]

### Damage

[edit]

Despite the earthquake's large magnitude, no major structural damage was reported from any of the population centres in the vicinity.[15] This can be explained by the remoteness of the tremor's epicentre. No casualties or major injuries were recorded from the quake, likely due to the sparsely populated nature of the region, but in Hawaii, one person died in a car crash near a road that was closed because of the tsunami threat near Oahu's northern coast.[3][9] As a result of the earthquake and its aftershocks, the famed hot springs in Gwaii Haanas National Park on Hotspring Island dried up.[16] In 2015 the hot springs began to come back.[17]

### Aftershocks

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There were 94 aftershocks of magnitude 4.0 or greater lasting until November 7, as recorded by the USGS.

The largest of these numerous aftershocks was a 6.3 magnitude earthquake that occurred 56 kilometres (35 mi) to the west of the main tremor on the morning of October 28.[18] This was followed on October 29 by a 6.2 aftershock 50 kilometres (31 mi) to the south of the original quake.[19]

Four months after the mainshock, in January 2013, another magnitude 7.5 earthquake struck north of Haida Gwaii in southeastern Alaska.[20] The earthquake had a pure strike-slip focal mechanism, consistent with a rupture along the Queen Charlotte Fault. This earthquake is not considered an aftershock, but was triggered by stress transfer caused by the October 2012 earthquake.[21]

## See also

[edit]

* List of earthquakes in 2012
* List of earthquakes in Canada

## References

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1. ^ a b c d Bird, A. L.; Lamontagne, M. (2015), "Impacts of the October 2012 Magnitude 7.8 Earthquake near Haida Gwaii, Canada", Bulletin of the Seismological Society of America, 105 (2B), Seismological Society of America: 1178, 1180, Bibcode:2015BuSSA.105.1178B, doi:10.1785/0120140167
2. ^ a b USGS. "M7.8 - Haida Gwaii, Canada". United States Geological Survey.
3. ^ a b c "Tsunami Event: HAIDA GWAII, CANADA". NGDC.
4. ^ "Canada Earthquake: British Columbia Hit, Tsunami Warning For Alaska, Hawaii". Huffingtonpost.com. October 28, 2012. Retrieved October 28, 2012.
5. ^ Justine Hunter; Ian Bailey & Wendy Stueck (October 29, 2012). "Minor temblor rattles Los Angeles after strong quake off B.C. coast". Toronto: The Globe and Mail. Archived from the original on July 1, 2016. Retrieved October 28, 2012.
6. ^ CBC News (October 27, 2012). "Tsunami heads for Hawaii after huge B.C. quake". CBC. Retrieved October 28, 2012.
7. ^ a b "Magnitude 7.8 Quake Strikes Off Western Canada". The New York Times. The Associated Press. October 28, 2012. Retrieved October 28, 2012.
8. ^ "Superquakes, supercycles, and global earthquake clustering", Chris Goldfinger, Yasutaka Ikeda and Robert S. Yeats, EARTH, January 7, 2013.
9. ^ a b "B.C. tsunami warning came 39 minutes after U.S. alert - British Columbia - CBC News". Cbc.ca. October 30, 2012. Retrieved November 9, 2012.
10. ^ a b c "West Coast and Alaska Tsunami Information". Oldwcatwc.arh.noaa.gov. Retrieved November 9, 2012.[permanent dead link]
11. ^ DEREK SPALDING (October 28, 2012). "B.C. to review emergency response in wake of Haida Gwaii quake, communication problem with Tofino". Timescolonist.com. Archived from the original on November 2, 2012. Retrieved November 9, 2012.
12. ^ "As it happened: Hawaiian tsunami alert - ABC News (Australian Broadcasting Corporation)". ABC News. Abc.net.au. October 28, 2012. Retrieved November 9, 2012.
13. ^ "Tsunami messages issued in the past 7 days". Tsunami.gov. Retrieved November 9, 2012.
14. ^ Ocean Networks Canada. "Co-seismic tsunami hazard assessment for Prince Rupert" (PDF). The City of Prince Rupert Tsunami Flood Risk Assessment. Appendix C. Retrieved August 6, 2024.
15. ^ "Aftershocks continue to hit Haida Gwaii, 6.3 magnitude occurs right before noon". The Northern View. October 28, 2012. Archived from the original on November 1, 2012. Retrieved November 9, 2012.
16. ^ McKnight, Zoe (November 2, 2012). "Earthquake empties famed Haida Gwaii hot springs (with video)". Timescolonist.com. Archived from the original on November 5, 2012. Retrieved November 9, 2012.
17. ^ "3 years after earthquake, Haida Gwaii hot springs heating up again". CBC News. Retrieved October 28, 2017.
18. ^ "M6.3 - 177km SSW of Masset, Canada 2012-10-28 18:54:16 UTC". Earthquake.usgs.gov. Retrieved November 9, 2012.
19. ^ "Another earthquake rattles B.C. coast - British Columbia - CBC News". Cbc.ca. October 30, 2012. Retrieved November 9, 2012.
20. ^ "M 7.5 - Southeastern Alaska". earthquake.usgs.gov. USGS. Retrieved May 19, 2021.
21. ^ R. D. Hyndman (2015). "Tectonics and Structure of the Queen Charlotte Fault Zone, Haida Gwaii, and Large Thrust Earthquakes" (PDF). Bulletin of the Seismological Society of America. 105 (2B): 1058–1075. Bibcode:2015BuSSA.105.1058H. doi:10.1785/0120140181. Retrieved May 19, 2021.

## Further reading

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* Leonard, L. J.; Bednarski, J. M. (2014), "Field Survey Following the 28 October 2012 Haida Gwaii Tsunami", Pure and Applied Geophysics, 171 (12): 3467–3482, Bibcode:2014PApGe.171.3467L, doi:10.1007/s00024-014-0792-0, S2CID 129536882

## External links

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* USGS: M7.7 - 139km S of Masset, Canada 2012-10-28 03:04:10 UTC
* Natural Resources Canada: 2012-10-27: M=7.7 - 74 km SSW of Queen Charlotte City, BC Saturday October 27, 2012
* West Coast and Alaska Tsunami Warning Center: 2012-10-28
* Pacific Tsunami Warning Center: Pacific archive Archived October 31, 2012, at the Wayback Machine
* Pacific Tsunami Warning Center: Hawaii archive Archived November 15, 2012, at the Wayback Machine
* M7.7 Haida Gwaii region, Canada earthquake of 28 October 2012 – United States Geological Survey
* Tsunami Animation: Haida Gwaii, Canada October 27, 2012 – Pacific Tsunami Warning Center
* The International Seismological Centre has a bibliography and/or authoritative data for this event.

* v
* t
* e

← Earthquakes in 2012 →

February|

* Visayas, Philippines (6.7, Feb 6)†

March|

* Chiba, Japan (6.1, Mar 14)
* Guerrero–Oaxaca, Mexico (7.4, Mar 20)
* Talca, Chile (7.1, Mar 25)

April|

* Indian Ocean (off Sumatra, Indonesia) (8.6, Apr 11)

May|

* Pernik, Bulgaria (5.6, May 22)
* Emilia-Romagna, Italy (6.1, May 20 – 5.8, May 29 – 5.1, June 3)

June|

* Baghlan, Afghanistan (5.4 and 5.7, June 11)†
* Gippsland, Australia (5.2, June 19)

July|

* North Island, New Zealand (6.3, July 3)

August|

* East Azerbaijan, Iran (6.4, Aug 11)†‡
* Usulután, El Salvador (7.3, Aug 26)
* Samar, Philippines (7.6, Aug 31)

September|

* Nicoya Peninsula, Costa Rica (7.6, Sep 5)
* Yunnan, China (5.6, Sep 7)†

October|

* Haida Gwaii, Canada (7.7, Oct 27)

November|

* Guatemala (7.4, Nov 7)†
* Shwebo, Myanmar (6.8, Nov 11)

December|

* Zohan, Iran (5.6, Dec 5)
* Kamaishi, Japan (7.3, Dec 7)

* † indicates earthquake resulting in at least 30 deaths
* ‡ indicates the deadliest earthquake of the year

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* e

Earthquakes in Canada

Historical|

* 1663 Charlevoix
* 1700 Cascadia
* 1732 Montreal
* 1870 Charlevoix
* 1872 North Cascades

20th Century|

* 1918 Vancouver Island
* 1925 Charlevoix–Kamouraska
* 1929 Grand Banks
* 1933 Baffin Bay
* 1935 Timiskaming
* 1944 Cornwall–Massena
* 1946 Vancouver Island
* 1949 Queen Charlotte Islands
* 1985 Nahanni
* 1988 Saguenay
* 1989 Ungava

21st Century|

* 2000 Kipawa
* 2001 Nisqually
* 2007–2008 Nazko
* 2010 Central Canada
* 2012 Haida Gwaii
* 2013 Craig

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