2012 Haida Gwaii earthquake

Coordinates: 52°46′08″N 131°55′37″W / 52.769°N 131.927°W / 52.769; -131.927
Source: Wikipedia, the free encyclopedia.

2012 Haida Gwaii earthquake
PDT)
Duration90 seconds [1]
Magnitude7.8 Mw
Depth17.5 km (10.9 mi)
Epicenter52°46′08″N 131°55′37″W / 52.769°N 131.927°W / 52.769; -131.927
TypeThrust[1]
Areas affectedCanada
Max. intensityMMI V (Moderate)[2]
Peak acceleration0.2 g[1]
TsunamiYes
Casualties1 dead (indirect)[3]

The 2012 Haida Gwaii earthquake occurred just after 8:04 p.m. PDT on October 27. The shock had a

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

Strong shaking was felt throughout Haida Gwaii where residents 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

Cascadia Subduction Zone to the south.[8]

Tsunami

A

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

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

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

References

  1. ^
    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 May 19, 2021.
  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. doi:10.1785/0120140181
    . Retrieved May 19, 2021.

Further reading

External links
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