five most recent earthquakes in canada

8/3/2019 Five Most Recent Earthquakes in Canada

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1. Five most recent earthquakes in Canaday October 9, 2011

o It happened offshore VancouverIsland, BC (50.7 N, 130.9 W) at 22:39:00 PDT(Pacific Daylight Time). The magnitude of earthquake was 4.3 Mw (moment

magnitude). It was not felt. (Government of Canada, 2011)

y October 2, 2011o It happened 99 km NNW of Mingan, QC (51.16 N, 64.43 W) at 04:22:51 EDT

(Eastern Daylight Time). The magnitude of earthquake was 3.9 MN1. It was not

felt.

y September 25, 2011o It happened 130 km W of Wrigley, NT (63.4 N, 126.2 W) at 19:02:57 MDT

(Mountain Daylight Time). The magnitude of earthquake was 5.6 ML. It was not

felt.

y September 18, 2011o It happened 16 km E of Buckingham, QC (45.58 N, 75.21 W) at 15:19:13 EDT

(Eastern Daylight Time). The magnitude of earthquake was 4.1 MN. It was felt.

y September 15, 2011o It happened 91 km WSW of Gold River, BC (49.4 N, 137.3 W) at 04:02:08 PDT

(Pacific Daylight Time). The magnitude of earthquake was 4.1 Mw (moment

magnitude).It was felt.

1 Earthquakes occurring in Eastern Canada measured with Nuttli magnitude


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2. Remember, earthquakescaused by plate tectonic

movements. The offshore

of British Columbia is a

spot where four plate

tectonics meet (North

American Plate, Explorer

Plate, Juan De Fuca Plate,

Pacific Plate) thus making that area very unstable, specifically west of VancouverIsland.

The area under VancouverIsland has plate boundaries that converge (move toward), diverge

(move away) and transform (sliding past each other). For instance, Juan De Fuca Plate slides

at 2-5 cm/year2 beneath North American Plate, which creates pressure within those plates

and then eventually can cause subduction earthquakes, an earthquake of great magnitude.

3. Large intraplate quakes do not occur very often but if one occurs it can cause significantdamage because infrastructures in the areas are not build to withstand those shocks. The most

active region in Eastern Canada is in St.

Lawrence Valley. Although the area is

under a stable North American Plate and

there are no other plates around to cause

friction, there are still significant

numbers of small earthquakes in the

region. This indicates that tectonic plates

2 Background on Earthquakes in Western Canada (www.nrcan.gc.ca)

Figure 1: Plates west of Vancouver Island (Ministry of Energy and

Mines and Responsible for Housing, 1991-6)

Figure 2: Occurrence of earthquakes in St. Lawrence

Valley


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can stress not only at their boundaries, but in the other areas as well. Most significant

earthquake that happened in Eastern Canada happened in Charlevoix on February 5, 1663 at

5:30 PM. The shock can be felt as far away as New England because it is on the same

intraplate. It is believed that on Richter scale the shock could not been greater than 7. (Smith,

1962)

4. The earthquake that is recognized as the largest in Canada happened in Cascadia subductionzone, British Columbia (48.5 N, 125 W) on January 26, 1700. The magnitude was estimated

to be 8.7-9.2 (Atwater, 2005). Mercalli scale measures the effects that an earthquake has on

Earths surface and its inhabitants (nature, infrastructure and humans). Based on damages

assessed to surroundings (houses destroyed, mass landslides) with no survivors near the

VancouverIsland (Pachena Bay village) it is fair to assume that it was X (10) or greater on

Mercalli Scale. In contrast, the

earthquake that happened in Chile on

May 22, 1960 at 19:11:14 UTC

(Coordinated Universal Time) had

magnitude of 9.5 Mw. This nature

disaster accounted for 1655 deaths,

3000 injured, 2,000,000 homeless,

$550 million in damages.3Keep in mind that earthquake doesnt cause much of devastation;

its what comes after the shock. Tsunamis cause most of the damage as they sweep away

anything that is in their path. In terms of damage caused, we dont have much information on

BC earthquake except personal journals of people that resided in the region. In one of the

3 Numbers are taken from USGS The Largest Earthquake in the World

http://earthquake.usgs.gov/earthquakes/world/events/1960_05_22.php

Figure 3: Earthquake in Valdivia, Chile (Amand, 1960)


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accounts mentioned the shock being strong enough that it was felt all the way in Oregon, US;

many objects of nature submerged under water and entire local population wiped out.

5. Frequency of earthquakes in Canada will increase in eastern parts (St. Lawrence Valley) notso much in other areas but it is important to know that more areas will develop that will be

prone to seismic activities due to higher viscosity of lower mantle (Wu, 1997). Although

earthquakes can occur anywhere in the world, the greatest number of seismic activities

happens in areas that are known as being part of Ring of Fire (area with increased

frequency of diverging plates); unfortunately for Canada, British Columbia is part of it.

Seismologists worried that massive earthquake will hit west coast of BC since it is long

overdue. City infrastructures in the hot spots are developed according to protocol, however

many doubt that anything will prepare them for the mega earthquake.

6. Since the tragedy that happened in Japan many Canadians in BC seriously consideringoption of getting homeowners insurance plan. There is only one problem; loopholes that

were created by insurance companies are unfair to homeowner/renters because it works in

favor of the insurers. The two ways damages are done by earthquake; earthquake itself and

fire started as a result of the earthquake. Instead of offering one plan, insurance providers

divided it into fire protection and earthquake protection. Not only it is time consuming for

insurance company to figure out what caused the destruction (fire or earthquake) but it will

also hurt homeowner/businesses who had one way insurance. (Mohindra, 2011).

Works Cited

Amand, P. S. (1960). Earthquake damage to good quality, wood-frame houses in Valdivia.

Retrieved October 14, 2011, from

http://earthquake.usgs.gov/earthquakes/world/events/images/valdivia.gif


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Atwater, B. M.-R. (2005). The Orphan Tsunami of 1700. Professional Paper 1707.

Government of Canada. (2011, October 9). Earthquakes Canada. Retrieved October 13,

2011, from Natural Resources Canada: http://earthquakescanada.nrcan.gc.ca/index-eng.php

Ministry of Energy and Mines and Responsible for Housing. (1991-6). Retrieved October 13,

2011, from Earthquakes in British Columbia:http://www.em.gov.bc.ca/Mining/Geoscience/SurficialGeologyandHazards/Earthquakes/P

ublishingImages/eq-5y.gifMohindra, N. (2011, September 9). The major fault line in BCs earthquake insurance

regulations. Retrieved from Burnaby Now:

http://www.burnabynow.com/major+fault+line+earthquake+insurance+regulations/5379

518/story.html

Smith. (1962). Earthquakes of eastern Canada and Adjacent areas 1534-1927(Vol. 26).

Publications of the Dominion Observatory.

Wu, P. (1997). Intraplate Earthquakes and Postglacial Rebound in Eastern Canada and

Northern Europe. Geophysical Journal International, 130 (2), 365382.

five most recent earthquakes in canada

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