From 1970 to 1999, on average only 1 or 2 magnitude 2.5 or greater earthquakes have been recorded in this large area. A magnitude 3 event is sufficiently strong to be felt in the immediate area, and a magnitude 5 event is generally the threshold of damage. On average, an earthquake occurs in the Charlevoix region every day and a half. The seismic hazard map layer indicates the relative seismic hazard across Canada. In 1996 and 1997, two earthquakes of magnitude 4.4 and 4.3 occurred near Ste-Agathe-des-Monts, Quebec. Most earthquakes cluster along or between the mapped Iapetan faults (also called St. Lawrence paleo-rift faults). This probability is used in the National Building Code to help design and construct buildings that are as earthquake proof as possible. The map is a simplification of the National Building Code of Canada seismic hazard map for spectral acceleration at a 0.2 second period (5 cycles per second), and shows the ground motions that might damage one- to two-storey buildings. A Lower St. Lawrence earthquake occurs every five days on average. The damage potential of an earthquake is determined by how the ground moves and how the buildings within the affected region are constructed. Unlike the Charlevoix Seismic Zone, no large earthquake has ever been reported or recorded in the LSZ. As most earthquakes occur under the St. Lawrence River, between Charlevoix County on the north shore and Kamouraska County on the south shore, this region is also often referred to as the Charlevoix-Kamouraska Seismic Zone. Structural designers use this factor for earthquake resistant design of structures in Zone 5. The seismograph network of Earthquakes Canada can detect all events exceeding magnitude 3 in eastern Canada and all events magnitude 2.5 or greater in densely populated areas. In the region of moderate hazard, there is a 5 to 15 per cent chance that significant damage will occur every 50 years. Most occur faults that never reach the Earth’s surface. British Columbia is widely known to be Canada's seismic danger zone, but every so often the shifting Earth reminds us that the rest of the country isn't immune to the sometimes fickle movements of tectonic plates. The Laurentian Slope Seismic Zone comprises an area off Canada's southeast coast, which includes the Grand Banks of Newfoundland. Zone 5 covers the areas with the highest risks zone that suffers earthquakes of intensity MSK IX or greater. Located some 400 km downstream from Quebec City in the estuary of the St. Lawrence River, the Lower St. Lawrence Seismic Zone (LSZ) is a seismically active region of eastern Canada. Please tell us by filling out our earthquake questionnaire. Unlike plate boundary regions where the rate and size of seismic activity is directly correlated with plate interaction, eastern Canada is part of the stable interior of the North American Plate. Each year, approximately 450 earthquakes occur in eastern Canada. With the current network, all earthquakes larger than about magnitude 2 on the Richter scale can be located. CSZ earthquakes occur in the Canadian Shield, between the surface and 30 km depth, beneath Logan's line and the Appalachians. Due to its dense seismograph network, the CSZ is the only eastern Canadian region where the focal depth of earthquakes can be routinely calculated. Over the past 30 years, on average, 2 to 3 magnitude 2.5 or larger earthquakes have been recorded in the southern Great Lakes region. The causes of earthquakes in eastern Canada are not well understood. TORONTO -- Earthquakes Canada has reported a magnitude 4.5 earthquake in eastern Labrador. Most earthquakes occur under the St. Lawrence River, within a triangular zone defined by the towns of Baie-Comeau, Sept-Iles, and Matane on the south shore. The earthquake potential of the CSZ led the GSC to conduct two field surveys in 1970 and 1974. In these zones, earthquakes occur from near the surface to depths of 30 kilometres. 6); 1860 (Mag. In 1929 a large M7.2 earthquake occurred near the Grand Banks and was responsible for a large tsunami (seismic sea-wave) which tragically drowned 27 people when it came ashore on the Burin Peninsula in southern Newfoundland. NOTICE: The Canadian National Seismograph Network (CNSN) is undergoing equipment upgrades over the next few years. In 1929 a large M7.2 earthquake occurred near the Grand Banks. An earthquake occurs in the Western Quebec Seismic Zone every five days on average. International earthquake information United States Geological Survey Seismic activity in areas like these seems to be related to the regional stress fields, with the earthquakes concentrated in regions of crustal weakness. Small earthquakes are recorded regularly, indeed almost daily, in the region that includes Ottawa, Montreal, and Quebec City. The IS code assigns zone factor of 0.36 for Zone 5. Of this number, perhaps four will exceed magnitude 4, thirty will exceed magnitude 3, and about twenty-five events will be reported felt. Historically, the zone has been subject to five earthquakes of magnitude 6 or larger: in 1663 (Mag. 6 1/2); and 1925 (magnitude MS 6.2 ± 0.3). This region has a low to moderate level of seismicity when compared to the more active seismic zones to the east, along the Ottawa River and in Quebec. By comparison, over the same time period, the smaller region of Western Quebec experienced 15 magnitude 2.5 or greater earthquakes per year. Since the 1925 event was the only one recorded by seismographs, the previous events have approximate magnitudes evaluated using felt areas and damage. The Northern Appalachians Seismic Zone includes most of New Brunswick and extends into New England down to Boston. Overall, the distribution of historical and recent events shows an earthquake concentration between La Malbaie and Rivière-du-Loup. The pattern of historical seismic activity recorded by the Canadian seismograph network since the beginning of the century shows the earthquakes concentrating in two sub-zones: one along the Ottawa River and the second along a more active Montreal-Maniwaki axis.