This Earthquakes Canada site is the authoritative source of information on Canadian eathquakes. Available here, among other things:. No casualities were ever directly related to Canadian earthquakes. In fact, Canadian earthquakes have never caused the collapse of a building.
Only some injuries were caused by the fall of objects. Although it has been reported that a yound girl was killed during the Montreal earthquake , it has never been substanciated by independent sources. In Canada, the only loss of life related to an earthquake, although indirectly, were those caused by the tsunami created by the Grand Banks earthquake. While there are differences between the recordings of an earthquake and a nuclear explosion, the same basic instrumentation and measurement techniques apply.
Being geographically the second largest country in the world, Canada plays an important role in nuclear explosion monitoring. If you live in the East or the North of Canada, the presence of faults in your area is not indicative of a higher probability earthquakes. In these areas, the faults represent very old geological movements. The Geological Survey of Canada has produced maps for certain areas of Canada.
How we record earthquakes - Seismographs. How we record earthquakes - Seismic Waves. Building your own seismograph is possible, but it requires time and materials. If your project is due tomorrow, forget about it! If you have a little more time here is a reference:. The seismogram viewer is a display of vertical component seismic data recorded by a selection of our seismograph stations.
It is intended to provide qualitative information for the general public. The plots are delayed by about 5 minutes which is the time it takes to acquire the data and process it. The vertical scale has been adjusted to a level intended to suppress most local noise and emphasize Canadian earthquakes.
There is no simple correspondence between amplitude on the real-time seismogram viewer and earthquake magnitude, as it depends on the distance to the earthquake and other factors. Some recordings which can look quite large are actually just noise such as wind or human activity close to the seismograph station. See Interpreting Seismograms. If you require detailed technical information, you can download waveforms from our waveform archive ; however, using and interpreting the data may require specialized seismological software and expertise.
To find the magnitude of events, you can look at our recent significant earthquake reports and at the the last 30 days of Canada earthquakes. The first seismic hazard maps for use in Canada have been in use since This initial hazard map was a subjective assessment based on historical seismicity. In the first modern maps were developed using probabilistic methods. In two maps were produced, "acceleration" - suitable for use when designing small structures, and "velocity" - suitable for use when designing large structures.
The safest type of structure is a modern, well-designed, and well-constructed building. Generally, wood-frame houses perform very well during an earthquake. However, even these structures are prone to damage from soil failure, chimneys may be damaged or collapse, windows may break, interior walls may crack, and those houses not securely bolted to their foundation may fail at or near ground level.
For more information on your home and earthquakes, click here. Unreinforced masonary structures those not seismically upgraded are generally more vulnerable to earthquake damage. Falling objects pose the greatest danger during a major earthquake. In Canada, no house has ever collapsed during an earthquake. However, many types of objects may fall and cause damage or injuries. Of prime concern, therefore, is protection from falling objects such as framed pictures, light fixtures, plaster from ceilings or the upper part of walls, or chimneys which may fall outside or through the roof into the house.
To learn more about earthquake preparedness, follow the links at Preparing for earthquakes. For more information on earthquake preparedness and what to do during and after earthquakes, follow the links at Preparing for earthquakes.
The magnitude or size of an earthquake, distance to the earthquake focus or source, type of faulting, depth, and type of material are important factors in determining the amount of ground shaking that might be produced at a particular site. The magnitude of an earthquake, for instance, influences ground shaking in several ways. Large earthquakes usually produce ground motions with large amplitudes and long durations.
Generally speaking, Canadian wood-frame houses are well able to withstand vibrations generated by earthquakes - even very large ones. Moreover, modern buildings must be designed according to national or provincial building code standards, which are intended to minimize the probability of building collapse in major earthquakes.
However, building codes do not prevent certain types of non-structural damage. Thus, it is possible that cracks may be seen on some walls. Unreinforced masonry e. Vibrations may also cause ground settlement under a house.
Sometimes this may cause small cracks in the basement or warping of walls. These are indirect effects that do not indicate that a fault lies near the house. For more on the effects of earthquakes on buildings, see section 4 above, "Seismic Hazards and Earthquake Engineering. FAQ - What is a seismologist? In the hour immediately following a relatively large earthquake, GSC Seismologists locate the earthquake and measure its magnitude.
They use data supplied by the national seismograph network , which feeds continuous data 24 hours per day to the Ottawa and Sidney, BC offices. During the following hours, the seismologists decide whether it would be feasible to conduct a field survey to learn more about the geological environment where the earthquake occurred, and to record any aftershocks that might occur in the ensuing hours and days.
In a field survey, seismologists set up portable seismographs to measure any further release of energy through small earthquakes. This information is analyzed in the weeks and months after the main earthquake and permits scientists to better understand the phenomenon of earthquakes in Canada. In the short term, this information cannot be used to predict earthquakes. In the long term, it will provide the basis for a more comprehensive understanding of seismic activity in the region.
Also, if the earthquake was large, other scientists specializing in surface deposits clay, sand may join the field survey team. Engineers may also come to inspect buildings to better determine the effects of the earthquake. Some of these specialists may return again after several months to gather additional data. Skip to main content Skip to "About this site". What causes earthquakes? How do earthquakes cause damage? Does the earth open up during an earthquake? Where do earthquakes occur? What is the relationship between volcanoes and earthquakes?
Will more shocks be felt after a strong earthquake? Can earthquakes be predicted? Does the rate of earthquakes increase during the cold weather? Are there certain months of the year that are more seismically active than others? What is the intensity of an earthquake? Can people cause earthquakes? Does a small earthquake mean that a larger earthquake is coming? Magnitude What is the "magnitude" of an earthquake?
Why are there so many earthquakes in the Geysers area in Northern California? The major seismic hazards in the region are from large earthquakes occurring along regional faults that are located miles away from the geothermal field, such as the San Andreas and Healdsburg-Rodgers Creek faults. However, activities associated with Foreshocks, aftershocks - what's the difference? Foreshocks are earthquakes that precede larger earthquakes in the same location.
An earthquake cannot be identified as a foreshock until after a larger earthquake in the same area occurs. Aftershocks are smaller earthquakes that occur in the same general area during the days to years following a Can the position of the moon or the planets affect seismicity?
Earthquakes are equally as likely to occur in the morning or the evening. Many studies in the past have shown no significant correlations between the rate of earthquake occurrence and the semi-diurnal tides when using large earthquake catalogs. Several recent studies, however, have found a correlation between earth tides caused by the position of Filter Total Items: 7.
Geological Survey The mission of the USGS in natural hazards is to develop and apply hazard science to help protect the safety, security, and economic well-being of the Nation.
Perry, Suzanne C. View Citation. Natural Hazards Science at the U. Year Published: Earthquake hazards: a national threat Earthquakes are one of the most costly natural hazards faced by the Nation, posing a significant risk to 75 million Americans in 39 States. Year Published: The severity of an earthquake The severity of an earthquake can be expressed in terms of both intensity and magnitude.
Geological Survey. Year Published: This dynamic earth: the story of plate tectonics In the early s, the emergence of the theory of plate tectonics started a revolution in the earth sciences. Kious, W. Jacquelyne; Tilling, Robert I. Year Published: Our changing continent Where were the land areas and oceans of the North American Continent one million years ago, compared to our present geography? Filter Total Items: 3. Date published: March 1, Attribution: Science Application for Risk Reduction.
However, the vast majority of earthquakes occur at the boundaries between tectonic plates. Continental and oceanic plates may move toward each other, scrape past each other, or pull apart as they move slowly across the planet's upper mantle.
This movement of the plates, and the pressure that is built up at the boundaries, can result in earthquakes. The boundaries between plates contains systems of deep cracks, called faults. Most earthquakes occur along these faults. Within a fault , rock masses on either side of the break are pushed by geologic forces in opposite directions.
Friction , however, holds the rocks in place, causing stresses to build. Finally, the mounting pressure overcomes the friction and a sudden movement occurs along the fault, releasing a large amount of energy. This is an earthquake. While the vast majority of earthquakes occur along faults at Earth's plate boundaries, occasionally, a quake occurs in the middle of a plate, far from any boundary. Such quakes make up less than 10 percent of all earthquakes. Although rare and not well understood, these earthquakes are no less devastating than those that occur along plate boundaries.
Earthquakes along the New Madrid Fault, along the Mississippi River in the United States, in — were among the strongest quakes ever recorded.
This map is best viewed in full screen mode. To enter full screen mode use button below the zoom controls. Click on the map circles for more information. Earthquakes are among the most deadly natural hazards.
They strike without warning and many earthquake zones coincide with areas of high population density. Seismometers are used to record the seismic waves produced by earthquakes. Relative arrival times of these waves is used to determine earthquake location. The extent of damage an earthquake causes depends not only on the magnitude of the earthquake, but also on local geology and on building techniques.
The causes of earthquakes and the different types of tectonic boundaries and faults on which they usually occur. Where do earthquakes occur? Discovering Geology — Earthquakes.
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