0 100 200 km

Kingston

Toronto

Gatineau Ottawa

Montreal

2010/06/23 M 5.0

MagnitudeM < 3 M 3 M 4 M 5 M 6

1935

1944

1732

2000

2002

Origin Time June 23, 2010 1:41 pm EDTMagnitude (Mw) 5.0Latitude 45.88 ºN Longitude 75.48 ºW Depth 22 km

The June 23, 2010 Val-des-Bois, Quebec earthquake was the one of the largest recent events in eastern Canada. This earthquake produced the strongest shaking ever felt in Ottawa. It was felt widely in Ontario and Quebec, and it was also felt into the United States as far as Kentucky. Some damage occurred in the epicentral region.

The magnitude (M) 5.0 Val-des-Bois, Quebec earthquake occurred in a region of moderate earthquake activity known as the West Quebec seismic zone. This broad region of activity extends from northern New York State through eastern Ontario and western Quebec (see map). On average, 150 earthquakes, most of them too small to be felt, are recorded here each year. The largest historically damaging earthquakes in this region include a M6 near Montreal (1732), a M6.2 near Timiskaming (1935) and a M5.8 near Cornwall (1944). Recently, 2 moderate earthquakes have occurred near Timiskaming (2000, M 4.7) and Plattsburgh, NY (2002, M 5.1). Like the Val-des-Bois event, both of these moderate sized earthquakes were widely felt in Ontario, Quebec and the northern United States.

The West Quebec Seismic Zone

Record of the shaking in Ottawa

Damage to a church from a falling chimney in Gracefield, QC (Adrian Wyld, The Canadian Press)

The 2010 Val-des-Bois Quebec EarthquakeEarthquake Summary

The shaking experienced in Ottawa from the Val-des-Bois earthquake is probably the strongest that the city has experienced in the past 200 years. Despite this, the estimated shaking from the recorded ground motions for Ottawa are well below the design level of shaking used in the 2005 National Building Code of Canada. For one or two storey structures the shaking from the Val-des-Bois event is about one fifth the design shaking.

1:41:40 pm :50 1:42:00 :10 :20 :30

Origin time

P wave arrival

S wave arrival

The Origin time (1:41:41 pm local time) is the actual time the earthquake started.

Primary waves travel at about 6 km/second and take roughly 10 seconds to arrive. These may have been noticed as .light shaking

Secondary waves travel at 3.5 km/second and take 17 seconds to arrive. These waves are much larger in amplitude and they would have generated the strong shaking that was widely felt.

The amplitude dies off fairly quickly, being significantly lower even just 10 seconds after the S waves began to arrive.

10 seconds

Ottawa seismogram

© Her Majesty the Queen in Right of Canada 2010. Aussi disponible en francais

Government of Canada work on earthquakes is undertaken by Natural Resources Canada’s Earth Sciences Sector.

For more information on earthquakes visit theGeological Survey of Canada, NRCan website:EarthquakesCanada.nrcan.gc.ca

Geological Survey of Canada7 Observatory CrescentOttawa, ON K1A 0Y3

Tel: 613-995-5548 (English)Tele: 613-995-0600 (French)info@seismo.nrcan.gc.ca

In the hours following the earthquake, six portable seismographs were installed to record aftershocks. To the end of September, 2010 288 aftershocks were located. The majority of these (244) ocurred in the first week following the event. The largest aftershock was magnitude 3.3 – five of the aftershocks were reported felt.

Aftershocks and Field Stations

Damage and Intensity ReportsDistribution of Val-des-Bois aftershocks in space (left) and time (right)

0.00 0.60 1.20 1.80 2.50 3.10 3.85 4.70 5.30 6.00

I II - III IV V VI VII VIII IX X+

Not felt Weak Light Moderate Strong Very Strong Severe Violent Extreme

none none none Very light Light Moderate Moderate/Heavy Heavy Very Heavy

INTENSITY

SHAKING

DAMAGE

Chimney damage,Ottawa, ON(Garth Gullekson, The Ottawa Citizen)

Damage to supermarket contents, Gracefield, QC (Stéphane Kelly, Mon Topo)

Landslide triggered by the earthquake, Mulgrave-et-Derry, QC (Didier Perret, Natural Resources Canada)

0

1

2

3

4

5

Magnitude

27 04 11 18 25 01 08 15 22 29 05 12 19 26

June 2010 July 2010 August 2010 September 2010

many smaller aftershocks unlocated

Embankment failure south of Bowman, QC(Jean Levac, The Ottawa Citizen)

400 metres

Landslide triggered by the earthquake, Notre-Dame-de-la-Salette, QC (Ministry of Transport, Quebec)

0 500km

Montreal Ottawa

Quebec

Toronto

Boston

BuffaloDetroit

Halifax

New York

Washington

Cleveland

Cincinnati

PittsburghIndianapolis

0 10 20km

Ottawa

Gatineau

Kanata

Buckingham

Constance Bay

Metcalfe

Orleans

Greely

Manotick

Barrhaven

Nepean

Stittsville

Dunrobin Navan

Carlsbad Springs

Luskville

Aylmer

Hull

Carp

Old Chelsea

Cantley

0 10km

Val-des-Bois

Notre-Dame-du-Laus

Notre-Dame-de-la-Salette

Mulgrave-et-Derry

Magnitude1

2

3

5Field Station

mainshock