Self Defense that begins with the Self
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An earthquake occurs when rocks break and slip along a fault in the earth. Energy is released during an earthquake in several forms, including as movement along the fault, as heat, and as seismic waves that radiate out from the “source” in all directions and cause the ground to shake, sometimes hundreds of kilometers away.
Earthquakes are caused by the slow deformation of the outer, brittle portions of “tectonic plates”, the earth’s outermost layer of crust and upper mantle. Due to the heating and cooling of the rock below these plates, the resulting convection causes the adjacently overlying plates to move, and, under great stress, deform. The rates of plate movements range from about 2 to 12 centimeters per year. Sometimes, tremendous energy can build up within a single, or between neighbouring plates. If the accumulated stress exceeds the strength of the rocks making up these brittle zones, the rocks can break suddenly, releasing the stored energy as an earthquake.
Most earthquake damage is caused by ground shaking. The magnitude or size (energy release) of an earthquake, distance to the earthquake focus or source, focal depth, type of faulting, and type of material are important factors in determining the amount of ground shaking that might be produced at a particular site. Where there is an extensive history of earthquake activity, these parameters can often be estimated. In general, large earthquakes produce ground motions with large amplitudes and long durations. Large earthquakes also produce strong shaking over much larger areas than do smaller earthquakes. In addition, the amplitude of ground motion decreases with increasing distance from the focus of an earthquake. The frequency content of the shaking also changes with distance. Close to the epicenter, both high (rapid) and low (slow)-frequency motions are present. Farther away, low-frequency motions are dominant, a natural consequence of wave attenuation in rock. The frequency of ground motion is an important factor in determining the severity of damage to structures and which structures are affected.
No! A common misconception is that of a hole in the ground that opens during an earthquake to swallow up unfortunate victims. This has nothing to do with reality but is Hollywood’s version of earthquakes. After a strong earthquake, some cracks may be seen on the ground or in basements. These are not faults, nor are they crevasses ready to close up again. Theses cracks are probably due to soil settlement caused by the ground shaking.
Earthquakes occur all over the world; however, most occur on active faults that define the major tectonic plates of the earth. 90% of the world’s earthquakes occur along these plate boundaries (that represent about 10% of the surface of the earth). The “Ring of Fire” circling the Pacific Ocean, and including Canada’s west coast, is one of the most active areas in the world.
The earthquake activity of numerous volcanoes is closely monitored to provide warning signs of an imminent eruption. Large volcanic eruptions, especially the explosive type, can release huge amounts of energy that can be recorded by seismographs even far from the source.
Recent volcanic activity in Canada has been experienced in BC and the Yukon. Worldwide, the majority of volcanoes and earthquakes are located in the same areas. This relationship is explained through a geological model called plate tectonics. You can find additional explanations on plate tectonics:
In Eastern and Northern Canada, earthquakes are not related to volcanic processes. Although volcanic rocks exist in many regions (sometimes as old as 2 billions years of age) and magmatic bodies can be found (the Monteregian Hills of Quebec are 60 million year old intrusives), these magmatic events are just too old to have any relationship with current earthquake occurrences. No volcanic or magmatic activity is currently underway in these parts of Canada.
For more information on volcanoes in Canada, see Volcanoes of Canada (GSC).
For several hours, or even days, after a strongly felt earthquake, it is quite possible that people may feel more shocks. This possibility always exists, but keep in mind these four facts:
It is impossible to predict either the number or the magnitude of aftershocks that might occur. These vary greatly from one region to another, according to many factors which are poorly understood.
With the present state of scientific knowledge, it is not possible to predict earthquakes and certainly not possible to specify in advance their exact date, time and location.
However, a great deal of research is being conducted to develop reliable prediction methods. Canada, along with other countries, is working to minimize damage and injuries through the implementation of modern earthquake-resistant standards so people will be protected whenever and wherever an earthquake occurs.
Although cold temperatures greatly affect the ground near the surface, it has no effect at greater depths. Near the surface, freeze and thaw cycles can weaken and break rock due to high water pressure. However, this is a phenomenon limited to near surface soil.
Consider a mine: the temperature inside the mine will be influenced by surface temperature only for about the first 50 m. Deeper in the mine the temperature will be influenced by the internal heat of the earth – a temperature that is relatively constant throughout the year.
The hypocentre (the place where displacement occurs along a rock fracture) of an earthquake is generally located several km below the surface (on average, between 5-30 km in Eastern Canada), where the surface temperature would have no influence. For example, the hypocentre of the 1988 Saguenay earthquake occurred at a depth of 28 km where the temperature is approximately constant at 300°C year round.
Furthermore, the principle causes of earthquakes (movement of tectonic plates, volcanoes, etc.) are large scale phenomena, unrelated to surface temperature.
However, close to lakes and rivers, when the ambient temperature drops below -20°C many little microseisms may be heard and are sometimes felt. These microseisms are not earthquakes as they are caused by cracking ice and movements of ice blocks one against another. They are cryoseisms, also known as frost quakes, and can only be felt close to the body of water from which they originate. Such ice cracks can sometimes be detected by a seismograph if it is located close to the body of water.
Seismic trace of a typical frost quake recorded on the vertical component of the seismic station in Sadowa, Ontario, near Georgian Bay (SADO), January 18, 2000 at 6:55 pm, a very cold night (12 frost quakes were recorded within 2 hours that night). A seismologist immediately recognizes the nature of such an event by the single frequency contained in the record.
No, there are no months that have more earthquakes than others. Examining the list of Canadian or global earthquakes, there isn’t a season that stands out as having an increased number of earthquakes.
The explanation for this can be found by considering that the mechanisms that cause earthquakes are independent of seasonal temperature changes ( see effects of cold temperatures on earthquakes ), and independent of the changes in position of the Earth in the solar system at different times of the year. It is internal geological forces that play the most important role in generating earthquakes.
Most large earthquakes are as a result of immense continental plates, called tectonic plates, that move, one with respect to another. The driving force for this movement is found in the Earth’s mantle in the form of convective currents. These currents carry the tectonic plates around the Earth generating earthquakes and volcanic eruptions. The movement of the plates creates strain which is then accumulated in faulted areas causing earthquakes. Both the movement of the plates and the accumulation of strain along faults are continual processes independent of the time of year.
Since the distance between the Earth and Sun changes throughout the year due to the elliptical trajectory of the Earth around the Sun, it seems possible that the attractive gravitational forces between the two bodies might cause extra strain in the Earth’s crust. However, strain models have shown that this extra force is insignificant compared to the tectonic force present.
Since the temperature and gravitational forces are the only forces changing with the seasons, seasonal effects can be eliminated as a factor in influencing the frequency of earthquakes.
See the Modified Mercalli Intensity Scale.
Yes! Minor earthquakes have been triggered by human activities such as mining (rockbursts and cavity collapse), the filling of reservoirs behind large dams, and the injection of fluids into wells for oil recovery or waste disposal. Large dams hold back enormous quantities of water. Some of this water may penetrate into cracks in the underlying rock, and sometimes this may trigger small earthquakes under or very near the reservoir.
Following an underground nuclear explosion, small earthquakes have often been recorded near the test site. These are due to the collapse of the cavity created by the explosion.
Man-made earthquakes always occur close to the site of the activity. There is no link between human activities like these and earthquakes occurring hundreds or thousands of kilometres away.
No, except for very rare exceptions. Every year, hundreds of earthquakes occur in Canada. Only a very tiny minority of these precede a larger earthquake.
Although a large earthquake may be preceded by a foreshock (the Saguenay earthquake of November 1988 is an example), the occurrence of a small earthquake is not in itself a typical sign. Hundreds of small earthquakes occur every year in Canada, whereas major earthquakes have occurred only a few times in this century.
A small earthquake, however, provides an ideal opportunity to offer reminders about safety measures to take before, during and after an earthquake.
Magnitude is a measure of the amount of energy released during an earthquake. It is frequently described using the Richter scale. To calculate magnitude, the amplitude of waves on a seismogram is measured, correcting for the distance between the recording instrument and the earthquake epicentre. Since magnitude is representative of the earthquake itself, there is only one magnitude per earthquake.
Taking the Saguenay QU earthquake of November 25, 1988 as an example, one could not therefore speak of magnitude 6 at Quebec City and magnitude 4 to 5 at Montreal. The effects (or intensities) experienced at different places were different, but the magnitude of the earthquake is unique; in this example, it was 6 on the Richter scale. Magnitude thus has more to do with the effects of the earthquake overall.
The magnitude scale is logarithmic. This means that, at the same distance, an earthquake of magnitude 6 produces vibrations with amplitudes 10 times greater than those from a magnitude 5 earthquake and 100 times greater than those from a magnitude 4 earthquake. In terms of energy, an earthquake of magnitude 6 releases about 30 times more energy than an earthquake of magnitude 5 and about 1000 times more energy than an earthquake of magnitude 4.
It is very unlikely that an earthquake of magnitude less than 5 could cause any damage.
The Intensity scale is designed to describe the effects of an earthquake, at a given place, on natural features, on industrial installations and on human beings. The intensity differs from the magnitude which is related to the energy released by an earthquake.
Without going into the seismological details, the magnitude defined by Charles Richter is the source of all magnitude scales. Over the years however, it was realized that the magnitude that Richter had defined for California (ML means local magnitude), did not apply to Eastern North America where the seismic waves attenuate differently. Otto Nuttli, a seismologist at the University of Saint-Louis in the United States, developed a magnitude formula which corresponded better to the reality of Eastern America. One of the formulas which Nuttli derived is used to measure the seisms of Eastern Canada. The formulation used is called Magnitude Nuttli or mN. In order to simplify communication with the public, Canadian seismologists will often refer to the Richter magnitude whereas strictly speaking the seisms that occur in Eastern Canada are measured according to the Nuttli magnitude. An exception exists for the very small earthquakes of the Charlevoix Region, where the Richter scale is used. Around the world other scales of magnitude exist according to the source conditions of the earthquakes (depth), the conditions of attenuation, the type of measured wave, etc. More and more, seismologists describe earthquakes according to the magnitude of the moment scale (MW or M).
No, it is not an error. As magnitude calculations are based on a logarithmic scale, a ten-fold drop in amplitude decreases the magnitude by 1. Let us assume that on a seismogram:
Naturally, a negative magnitude is found only for very small events, which are not felt by humans.
Though theoretically there is no mathematical limit with the magnitude calculation, physically there is a limit. The magnitude is related to the surface area of the blocks of rock which rub together and in doing so give rise to seismic waves. Since the tectonic plates have finite dimensions, the magnitude must therefore also reach a maximum. It is believed that the greatest earthquakes can reach magnitude 9.5, which corresponds to the magnitude of the Chilean earthquake described below.
This is difficult to answer absolutely. According to past earthquakes , one can however draw up some general information for Eastern Canada.
Though seismologists generally refer to magnitude on the Richter scale, several magnitude scales do exist. The United States Geological Survey (USGS) site describes several.
Global Frequency of Earthquakes
In addition to the international networks which can detect earthquakes of magnitude 5.0 and greater, the majority of the countries have their own national network. All these networks are listed on the University of Washington site.
No, earthquakes occur at more or less at the same rate every year. For more info: USGS web site
The greatest earthquake of recent history is the Chilean earthquake of May 22, 1960, which is estimated at magnitude 9.5. According to the USGS, this earthquake caused the death of more than 2000 people in Chile, in addition to generating a tsunami which propagated around the Pacific, adding several hundreds of victims to the assessment. The greatest world earthquakes since 1900 are described on the USGS site.
On average, the Geological Survey of Canada (GSC) records and locates over 4000 earthquakes in Canada each year. That is about 11 per day! Of these 4000, only about 50 (1/week) are generally felt.
Earthquakes occur across much of Canada. Most earthquakes occur along the active plate boundaries off the British Columbia coast, and along the northern Cordillera (southwestern corner of the Yukon Territory and in the Richardson Mountains and Mackenzie Valley) and arctic margins (including Nunavut and northern Quebec). Earthquakes also occur frequently in the Ottawa and St. Lawrence Valleys, in New Brunswick, and the offshore region to the south of Newfoundland.
Yes! Some of the world’s largest earthquakes have occurred here (see next question).
The largest earthquake recorded (during historic times) in Canada was a magnitude 8.1 event that struck just off the Haida Gwaii on Canada’s west coast on August 22, 1949. This earthquake (larger than the 1906 San Francisco earthquake) ruptured a 500-km-long segment of the Queen Charlotte fault and was felt over almost all of British Columbia, and as far north as the Yukon Territory and as far south as Oregon State.
Although not recorded by seismographs, the largest earthquake ever to strike Canada was undoubtedly the giant megathrust (subduction zone) earthquake of 1700 off the west Coast of Vancouver Island.
Every day! Scientists at the Geological Survey of Canada office near Sidney, B.C. record and locate approximately 1000 earthquakes each year in western Canada.
Yes! Some of the world’s largest earthquakes have occurred in western Canada. Click here to see the 5 most significant.
Western Canada is the most seismically active region in Canada. It consists of several discrete areas of [intense earthquake activity][eqcan 5y west eng] each corresponding to a particular plate tectonic regime. The most seismic of these regions is offshore, west of Vancouver Island. More than 100 earthquakes with a magnitude of 5 or greater have occurred here in the past 70 years. Most of the seismicity occurs in areas of fractured oceanic crust, which mark boundaries of small plates known as the Explorer and Juan de Fuca plates
Earthquake activity is also high in the Cascadia Subduction Zone. Here, the Juan de Fuca Plate dips below the easterly neighbouring North American plate. Thus, both deep (dipping plate) and shallow (overriding plate) earthquakes occur in this zone, though no earthquakes occur at the interface of the plates. Another region of high seismicity is defined by a zone of plate breakage or “faulting” immediately west of the Queen Charlotte Islands (“the Queen Charlotte fault”). Earthquakes of magnitude 7 occurred here in May of 1929 and June of 1970.
The St. Elias Mountains, southwest Yukon Territory and the extreme northwest of B.C., too, is a highly seismic region. This is because of plate margin deformation between two converging plates in the area (the “Pacific” to the west and “North American” to the east.) Finally, the Canadian Cordillera typically shows intense seismicity north of 60 degrees in a broad zone through the Mackenzie and Richardson Mountains. The largest earthquake recorded here, with magnitude of 6.9, occured in the Mackenzie Mountains in December, 1985. South of 60 N, seismicity drops off markedly away from the coast to a low level through much of the Cordillera, though it is slightly higher in the Coast Mountains from southern British Columbia to the Yukon Border.
See Geodynamics: Episodic Tremor and Slip (ETS)
Understanding earthquake hazards involves many types of studies: monitoring earthquakes, monitoring crustal deformation; mapping the marine environment for evidence of offshore earthquake activity; studying wave propagation; mapping earth structure; understanding local geological conditions; and looking for geological evidence of prehistoric earthquakes.
Many different types of studies are conducted by scientists at the Pacific Geoscience Centre of the Geological Survey of Canada to better improve our understanding of earthquake hazards in western Canada.
The recurrence time varies from subduction zone to subduction zone. In the Cascadia subduction zone 13 megathrust events have been identified in the last 6000 years, an average one every 500 to 600 years. However, they have not happened regularly. Some have been as close together as 200 years and some have been as far apart as 800 years. The last one was 300 years ago.
Megathrust earthquake are the world’s largest earthquakes. The last Cascadia earthquake is estimated at magnitude 9. A megathrust earthquake in Chile in 1960 was magnitude 9.5, and one in Alaska in 1964 was magnitude 9.2.
The Cascadia fault, on which megathrust earthquakes occur, is located mostly offshore, west of Vancouver Island, Washington, and Oregon, although it does extend some distance beneath the Olympic Peninsula of Washington State. The large distance between the Cascadia fault and the urban centres limits the level of shaking that the urban areas are exposed to.
The sudden submergence of the outer coast when a megathrust earthquake occurs kills vegetation which can be dated. Megathrust earthquakes also cause underwater landslides off the continental shelf into the deep ocean. The landslide deposits can be recognized in core samples taken from the ocean floor.
The deformation of the crust in a predictable pattern can be detected by very careful geodetic measurements using Global Positioning Satellites, precise levelling, micro-gravity measurements and changing distance measurements using laser technology.
No. Earthquake shaking, in the frequencies that damage buildings, increases to a maximum between a magnitude 7 and 8 earthquake, then the shaking simply involves a bigger area. However, the duration of shaking for a megathrust earthquake is much longer. It can be several minutes. This long duration can result in damage to some types of buildings that might not be damaged at the same strength of shaking produced by a smaller earthquake.
The Kobe earthquake was right beneath the city and the megathrust earthquake will be about 150 kilometres from Vancouver. The damage pattern would be very different. We can get a good example of the kinds of damage Vancouver can expect to experience if we look at what happened to Anchorage, Alaska, during the 1964 magnitude 9.2 megathrust earthquake. Anchorage is about the same distance from the Alaska subduction fault. Small buildings generally had little or no damage, unless they were affected by landsliding. Almost all the damage involved large buildings or large structures such as bridges.
No. Vancouver Island is part of the North American plate. The fact that there is water between Vancouver Island and the mainland is function of the current position of sea level. However, the west coast of Vancouver Island will drop as much as a metre or two when the next megathrust earthquake occurs.
No. Inland earthquakes, which are not as big but can be much closer to our urban areas and occur much more frequently, are our biggest earthquake hazard.
The thrusting motion of megathrust earthquake causes large vertical movement on the sea floor and this displaces a large volume of water which travels away from the undersea motion as a tsunami.
No. Just the coast exposed to the open Pacific is vulnerable to damaging tsunamis waves. The areas vulnerable to tsunamis are indicated in the red-tabbed pages of the telephone books published for the coastal communities of British Columbia.
West Coast and Alaska Tsunami Warning Centre (WCATWC) Message Definitions
Data from selected NRCan seismometers are forwarded to the National (United States) Oceanic and Atmospheric Administration’s (NOAA) West Coast and Alaska Tsunami Warning Centre (WCATWC) in Palmer, Alaska. This information is integrated with other seismic, tide gauge, and deep ocean buoy system data to produce tsunami information statements, alerts, watches, or warnings for all North American coastlines (including the Atlantic and Arctic). WCATWC distributes these messages to Emergency Measures Organizations (EMO) and other clients 5 to 15 minutes after a potentially tsunamigenic earthquake has occurred and provide updates at regular intervals.
WCATWC product definitions changed to the definitions provided below on February 12, 2008. The products issued by the center are warning, watch, advisory, and information statements. Each has a distinct meaning relating to local emergency response. In summary:
| Alert | Effect | Action | ||
|---|---|---|---|---|
| Warning | -> | Inundating wave possible | -> | Full evacuation suggested |
| Watch | -> | Danger level not yet known | -> | Stay alert for more info |
| Advisory | -> | Strong currents likely | -> | Stay away from the shore |
| Information | -> | Minor waves at most | -> | No action suggested |
Based on seismic data analysis or forecasted amplitude (dependent on whether the center has obtained sea level data), WCATWC will issue the appropriate product. Warnings and Advisories suggest that action be taken. Watches are issued to provide an early alert for areas that are distant from the wave front, but may have danger. Once the danger level is determined, the watch is upgraded to a warning or advisory, or canceled. The full definition of each message is given below and further details are available at http://wcatwc.arh.noaa.gov/, the WCATWC website.
Tsunami Warning – a tsunami warning is issued when a potential tsunami with significant widespread inundation is imminent or expected. Warnings alert the public that widespread, dangerous coastal flooding accompanied by powerful currents is possible and may continue for several hours after arrival of the initial wave. Warnings also alert emergency management officials to take action for the entire tsunami hazard zone. Appropriate actions to be taken by local officials may include the evacuation of low-lying coastal areas, and the repositioning of ships to deep waters when there is time to safely do so. Warnings may be updated, adjusted geographically, downgraded, or canceled. To provide the earliest possible alert, initial warnings are normally based only on seismic information.
Tsunami Watch – a tsunami watch is issued to alert emergency management officials and the public of an event which may later impact the watch area. The watch area may be upgraded to a warning or advisory – or canceled – based on updated information and analysis. Therefore, emergency management officials and the public should prepare to take action. Watches are normally issued based on seismic information without confirmation that a destructive tsunami is underway.
Tsunami Advisory – a tsunami advisory is issued due to the threat of a potential tsunami which may produce strong currents or waves dangerous to those in or near the water. Coastal regions historically prone to damage due to strong currents induced by tsunamis are at the greatest risk. The threat may continue for several hours after the arrival of the initial wave, but significant widespread inundation is not expected for areas under an advisory. Appropriate actions to be taken by local officials may include closing beaches, evacuating harbors and marinas, and the repositioning of ships to deep waters when there is time to safely do so. Advisories are normally updated to continue the advisory, expand/contract affected areas, upgrade to a warning, or cancel the advisory.
Tsunami Information Statement – a tsunami information statement is issued to inform emergency management officials and the public that an earthquake has occurred, or that a tsunami warning, watch or advisory has been issued for another section of the ocean. In most cases, information statements are issued to indicate there is no threat of a destructive tsunami and to prevent unnecessary evacuations as the earthquake may have been felt in coastal areas. An information statement may, in appropriate situations, caution about the possibility of destructive local tsunamis. Information statements may be re-issued with additional information, though normally these messages are not updated. However, a watch, advisory or warning may be issued for the area, if necessary, after analysis and/or updated information becomes available.
No. It takes many, many small earthquakes to release the amount of energy equivalent to a large earthquake. The amount of energy released increases about 40 times every time there is an increase of one unit on the magnitude scale. Thus, if we consider a small earthquake at the felt level, about magnitude 2, there would have to be 40x40x40x40x40x40x40 of these earthquakes to release the amount of energy as one magnitude 9 event. That is about one million small earthquakes a day, every day, for 500 years. That level of earthquake activity is not observed.
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 1732 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 1929 Grand Banks earthquake.
Yes! 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. You can consult what is available in the GEOSCAN database. If however you wish to obtain detailed geological maps of your area, you must contact your Provincial Office of Natural Resources.
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 1979 article is reproduced on the Redwood City (California) Public Seismic Network site.
Yes! Engineers can, and are, designing earthquake-resistant structures.
The first seismic hazard maps for use in Canada have been in use since 1953. This initial hazard map was a subjective assessment based on historical seismicity. In 1970 the first modern maps were developed using probabilistic methods. In 1985 two maps were produced, “acceleration” – suitable for use when designing small structures, and “velocity” – suitable for use when designing large structures.
Seismologists at the Geological Survey of Canada produce seismic hazard maps for use in the National Building Code of Canada.
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. For some examples of damage to typical wood-frame houses during the M=7.3 Vancouver Island earthquake of 1946, click below:
Unreinforced masonary structures (those not seismically upgraded) are generally more vulnerable to earthquake damage. For some photos of damage caused to unreinforced masonary structures during the M=7.3 Vancouver Island earthquake of 1946, click below:
Most earthquake damage is caused by ground shaking. 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. Where there is an extensive history of earthquake activity, these parameters can often be estimated.
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. Large earthquakes also produce strong shaking over much larger areas than do smaller earthquakes. In addition, the amplitude of ground motion decreases with increasing distance from the focus of an earthquake. The frequency content of the shaking also changes with distance. Close to the epicenter, both high (rapid)and low (slow)-frequency motions are present. Farther away, low-frequency motions are dominant, a natural consequence of wave attenuation in rock. The frequency of ground motion is an important factor in determining the severity of damage to structures and which structures are affected.
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.g. brick walls and chimneys) has little resistance to strong horizontal shaking and may collapse. 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.” See also How would your home stand up?
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. They pass this information on to the federal Office of Critical Infrastructure Protection and Emergency Preparedness, Provincial Emergency Program offices, to the news media – and, in Quebec, to the Quebec Provincial Police and to Hydro-Quebec.
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.
The above information can be found at Natural Resources Canada
The ONE simple practice that I would ask all women out there to implement is simple, keep your eyes open at all times and be aware! Not paranoid, but aware! For example: Don’t be talking on your phone with your head down oblivious to your surroundings, that makes you look like an EASY TARGET! In fact anytime you are out you shouldn’t be acting as though you are in the comfort of your own home. Be switched on! Know where you are and know who is looking at you. Don’t have your head down rummaging through your purse looking for your keys while you’re standing at your door, car, home, office, or otherwise! Don’t be an EASY TARGET! “Situational awareness and being aware of your surroundings” is a great start and simple enough to implement for keeping you and your loved one’s safe!
Author Mitra Castano is the Owner/Operator/kick boxing and self defense instructor of Triunity Martial Arts in Surrey, BC Canada. For more information about training with Mitra please call 778-578-0088 or see her website at www.triunitymartialarts.com
Canadian Legal Rights: Here in Canada, you have the “RIGHT” upon arrest or investigation to speak with legal counsel. I would hope that all of us here on the forum are “good guys and gals” and it is because of this fact, that unlike the bad guys who know to keep their mouth shut, we feel that we have to justify our reasons for defending ourselves because we were “lawfully” defending ourselves, and did nothing wrong. This “want” to justify our actions is a slippery slope that “could” mean the difference between freedom or incarceration!!!!
Remember that during a physical confrontation, Survival Stress Reaction (SSR) may likely take effect. One of the effects of SSR is something known as Critical Stress Amnesia (CSA). After a critical incident, it is not uncommon for a person to only recall approx 30% of what happened in the first 24 hours; 50% in the following 48 hours; and 75-95 % in 72-100 hours. As one can appreciate, this recall challenge could cause problems in a court of law down the road.
It is because of these above noted issues that I recommend that if being investigated as a possible suspect, you only provide a statement through a lawyer as there are a couple of advantages in doing so:
· In Canada you can not be cross examined on a statement that has been prepared by your lawyer
· Most lawyers, not all, are familiar with CSA and as a result will wait the appropriate amount of time before conducting a thorough interview which will be provided to the police later on.
If I were asked by the police to provide a statement (either verbal or written) I would give the following reply:
“ Officer, due to the fact that I was faced with a physical attack that I could not reasonably walk and talk my way out of, I responded with that amount of force needed to reasonably defend myself given the totality of the circumstances that will come to light in your investigation. I know that you would like me to provide a statement as to my perception of threat and the actions that I took to defend myself, and I will be more than happy to do so. However, given the fact that I am being investigated as a possible suspect, I want to ensure that I protect myself from any legal consequences (both criminal and civil) that may flow from my self defence actions, and as such, I will provide a voluntary statement to you through my lawyer as soon as possible.”
I believe that the above noted preamble is respectful and also sends a message that you will co-operate with police. I can only speak for LEO’s in my jurisdiction, and as such, I believe most would be very respectful and understanding of your legal concerns.
Remember, you may live by the sword, but you are judged by the pen. Although Shakespeare stated, “kill all the lawyers first”, a lawyer may be your best friend if being investigated by police for a self-defence action.
Author Darren Laur is currently a Staff Sergeant with the Victoria City Police Department, with over 25 years of policing experience. In 1993, both Darren and his wife Beth started their company, Personal Protection Systems Inc., which specializes in teaching safety awareness and self protection strategies, and both have presented to thousands of men, women, and children as well as to schools, businesses, and government ministries. Darren and Beth have written several books on the topics of personal safety, one of which won a provincial award. For more information go to www.personalprotectionsystems.ca
SELF DEFENSE VANCOUVER/RICHMOND BC
All stress comes from believing a thought that argues with reality. And when you oppose “what is” – it hurts.
In Byron Katie’s first book, Loving What Is, she illustrates this with a simple and clear example with a cat:
If you want reality to be different than it is, you might as well try to teach a cat to bark. You can try and try, and in the end the cat will look up at you and say, “Meow.” Wanting reality to be different than it is is hopeless. You can spend the rest of your life trying to teach a cat to bark…
And yet, if you pay attention, you’ll notice that you think thoughts like this dozens of times a day. “People should be kinder.” “Children should be well-behaved.” “My neighbors should take better care of their lawn.”…
These thoughts are ways of wanting reality to be different than it is. If you think that this sounds depressing, you’re right. All the stress that we feel is caused by arguing with what is.
So what can you do when you find yourself arguing with reality? You know, when you’re sitting in traffic thinking, “I shouldn’t be stuck in traffic right now!” Or when the sale you were hoping for at work falls through and you’re frustrated because, “They really should have followed through.”
Well, you can do one of two things:
1. Believe what you think.
2. Question it.
Believing what you think can be pretty painful. I mean just think about how stressful it is to sit in traffic wanting the cars to move faster! It’s about as hopeless as trying to get a cat to bark.
Questioning the thoughts, on the other hand, can open you up to finding peace where you once found stress.
You can start questioning them, or doing The Work, by writing down your stressful thought (the one where you want things to be different than they are) and then answering these four questions:
1. Is it true?
2. Can you absolutely know that it’s true?
3. How do you react when you believe that thought?
4. Who would you be without the thought?
Then you look for turnarounds by taking the original stressful belief and looking for opposites to see if they are as true or truer. In other words, to see if they are closer to reality.
Here’s an example:
My friend should be a better listener.
1. Is that true?
Yes.
2. Can you absolutely know that it’s true? (What’s the reality?)
The reality is that she’s not better than she is. So, no, I can’t know that she should be a better listener.
3. How do you react when you believe that your friend should be a better listener?
I get frustrated and I complain to my other friends. I don’t want to hang around with her anymore. I don’t want to listen to her either because I want to punish her. I don’t respect her and am jealous of her attention when she puts it somewhere other than on me when I’m trying to talk to her.
4. Who would you be without the thought that your friend should be a better listener?
I wouldn’t try to convince her that she should listen to me more. I’d feel gentler in my body. I’d appreciate the amount that she *does* listen to me. When she talked to me, I’d be able to listen because there wouldn’t be that resentment that I was holding on to. I’d realize that I’m doing just fine in my life even though she’s not listening to me more.
Turn the thought around: She should be a better listener.
TA> She should *not* be a better listener. This is true because she’s not. She can’t be a better listener than she is in that moment.
TA> *I* should be a better listener. Definitely! If I think she can do it, can I even do it?! I should give her what I want from her because obviously it’s important to me that friends listen to each other well. So this is for me to live.
The Work of Byron Katie is a path to self-discovery and freedom from stress. Ask these four questions for yourself and find out who you’d be without your story!
“When I argue with reality I lose. But only 100% of the time.” – Byron Katie
Author: Mona Grayson is a two-time graduate from The School for The Work of Byron Katie and has been helping people get free from the constraints of their stress so they can lead fuller, more peaceful lives. For more information about Mona, please go to www.monagrayson.com
For more information about “The Work of Byron Katie” please go to www.thework.com
SELF DEFENSE VANCOUVER/RICHMOND BC
“Everyone of us is shadowed by an illusory person: a false self..We are not very good at recognizing illusions, least of all the ones we cherish about ourselves. (34) Contemplation is not and cannot be a function of this external self. There is an irreducible opposition between the deep transcendent self that awakens only in contemplation, and the superficial, external self which we commonly identify with the first person singular.(7) Our reality, our true self, is hidden in what appears to us to be nothingness….We can rise above this unreality and recover our hidden reality….(281) God begins to live in me not only as my Creator but as my other and true self. (41)”
Thomas Merton, New Seeds of Contemplation
Thomas Merton was one of the most influential Catholic authors of the 20th century. A Trappist monk of the Abbey of Our Lady of Gethsemani, in the American state of Kentucky, Merton was an acclaimed Catholic spiritual writer, poet, author and social activist. Merton wrote over 60 books, scores of essays and reviews, and is the ongoing subject of many biographies. Merton was also a proponent of inter-religious dialogue, engaging in spiritual dialogues with the Dalai Lama, Thich Nhat Hanh and D. T. Suzuki. His life and career were suddenly cut short at age 53, when he was electrocuted stepping out of his bath.
SELF DEFENSE VANCOUVER/RICHMOND BC
I’ve often asked people, “If you were in a life or death situation that required you to fight for YOUR life, what would you fight for?” Almost 95% of the time the answer usually narrows down to one thing, my loved ones. I then ask, “What about YOU?” To which they reply, “What about ME?”
Do you see the problem with this? If you don’t, maybe this ONE Simple Practice is for YOU. Heck it might even change YOUR LIFE!
Here’s what YOU will need: 1 private room (bathroom works great, provided no one else is in there!), 1 mirror, and 1 candle. (both usually found in a bathroom)
Once you have what YOU need, go to your private room, light your candle and turn out the lights. Look into your mirror and repeat these 3 words: I – LOVE – YOU! Don’t come out until you believe it!
Because until YOU learn to love YOURSELF, YOU will continue to unnecessarily hurt YOURSELF and YOUR loved ones.
SELF DEFENSE VANCOUVER/RICHMOND BC
Most of the time as women we tend to conjure a particular image when we think of self defence. We usually think of being in a situation we have to fight our way out of against a bigger, stronger and usually male opponent.
Those of us who have thought more about self defence or trained in it, realise that it actually starts well before the physical altercation. In fact, if we have to physically defend ourselves, it sometimes means that our self defence hasn’t worked.
What is it then? Well among many other things, it’s awareness: listening to our intuition, putting in place our safety strategies, effective body language to show we’re not victims, and extremely importantly having a positive self belief.
And wouldn’t we all say that a major part of awareness and avoidance is not putting ourselves in a potentially dangerous situation in the first place?
Well yes, but that’s very easy for us to say when we’re feeling happy, positive, full of energy having had a good day. But what about when we’re stressed out after a bad day at work or a massive fight with our partner? What about when we’re tired after lack of sleep and a long day or we’re full of the flu? What about when we’ve been out with friends and had too much to drink to remember we should stick with our friends when we need to get home? What about when we’ve been out clubbing and spent a lot of money already that we don’t want to waste more on a taxi home?
It’s easy to say that self defence is looking after our body in every sense. It’s getting regular exercise, eating healthy food, avoiding drugs and alcohol, not letting stress get the better of us and much more. But as hard as I try to look after myself, I like a drink (or three) in the weekends, and let’s face it, so does the majority of the adult population. So we need to be practical, but we also need to be aware of the effect of too much alcohol on our ability to make rational decisions and how this affects our ability to look after ourselves.
So many times I have watched Police Ten-7 (our Crime Watch type reality Police TV show in New Zealand) and seen re-enactments of physical assaults on women who were intoxicated and walking home alone in the dark at 3am – every week there is a similar account. And while I am not taking anything away from these poor women who didn’t know any better, because it is NEVER the victims fault, I just always wish they realised in advance that an assault was one of the possible outcomes of their actions. To these people, it often just never even occurred to them when they were sober and definitely not when they were under the influence.
We often say at our seminars, when we are talking about awareness, that avoiding this sort of situation is just common sense. So then why does it happen so frequently? Because it is common sense to most of us … when we are sober.
Alcohol tends to make us think we are bullet proof. We’re suddenly less self-conscious (personally I become a fantastic singer!) and willing to take risks that we wouldn’t take when sober.
Say we’ve had a few drinks. I’m not talking about being so inebriated that we can’t stand or string a sentence together, say five or six drinks of whatever is your poison. We’re with a group of mates in town, having a great night. Someone walks towards us and shoulder barges us as they pass, intentional or not. What happens? Sometimes we can take this as an affront and don’t want to be seen as a coward or a pushover in front of our mates, so we have to defend our ego right? (Yes, women have huge egos too!). Generally this will end in, at best, a verbal altercation, or even worse, blows will be exchanged.
What if he has a weapon? What if all of your mates run off, and all of his decide to join in on the fun? We talk about always assuming that our aggressor has a weapon and friends, but are we going to remember this after a few drinks?
I know many well trained men and women who would normally diffuse a situation rather than have it go physical (even if they know they could take the person out) because they are aware of the potential aftermath of any violent confrontation. Yet these same people have been guilty of not only not diffusing the situation, but even escalating it when intoxicated. Either way, they take risks they wouldn’t normally take.
Hence the cases on Police Ten-7; walking home alone drunk from a bar at 3am, going to a public toilet alone in the middle of the night, or cutting through alleyways and parks for a quicker walk home. Now all of this to most of us seems potentially dangerous doesn’t it? However, imagine you’ve had a big night of drinking. You’ve already spent $100 at the bars and you’re ready to go home. Your mates are having way too much fun still and want to stay on. You’re faced with spending another $50 on a taxi when surely you can walk home safely. I mean, nothing’s really going to happen is it?
Now I would be a total hypocrite if I was to tell people not to drink, or even never to over-indulge. And even if I did, how many people would actually listen to me? But if we are going to drink, especially those of us who know you are going to drink a lot, we need to take some precautions.
Have a sober friend (hopefully you have a sober driver with you) keep an eye on you all night and make sure you get home safely. Or make a pact with a friend that, no matter how much you both drink, you will stay together until you are safely home or in a taxi.
Beware of people you haven’t met before paying for drinks all night for you. They are considering this an ‘investment’ in their chances of some later entertainment and may later use ‘loan-sharking’ against you to make you feel that you owe them something. Remember that alcohol is really the most common date rape drug!
Make sure you have enough cash or you have a credit card to enable you to get home safely. If its cash for a taxi, put it in a separate section of your wallet or purse so you don’t inadvertently spend it on drinks.
Always watch your drink being poured and if you have to leave it for any reason, consider it finished and get a new one when you come back. It takes a fraction of a second for someone to slip a date rape drug in your drink. Even asking a friend to watch your drink while you go to the loo isn’t foolproof. A lot of work has been done lately to colour these drugs so they are more noticeable but if you are drinking spirits with a mixer or a bottled drink like beer or RTDs, then this isn’t going to help you.
Yes, this is all common sense. But it’s important to think about worst case scenario BEFORE you go out and start drinking and PLAN in advance when you have the presence of mind that you may not have in a few hours.
About the Author: Athena Thompson is the co-founder of Protect Self defence and an instructor of group classes, seminars and courses in Auckland and throughout New Zealand.
She is the author of the highly influential book ‘Every woman’s guide to being safe…For life’, and the women’s self defence program that she designed, ‘Safe For Life’, carries the rare endorsement from Rape Prevention Education (formerly Rape Crises).
Athena has also been individually certified as a Senshido instructor (2006) and is the only female instructor in Australasia. She has lived what she teaches and shares a wealth of first-hand experience and knowledge on violence prevention for women.
She has had expert articles published in major magazines and newspapers, and is New Zealand’s leading female expert on the topic of self defence for women.
Athena has taught men and women from all walks of life including past survivors of rape and sexual assault, Police officers, security officers, corporate clients, teenagers, and many others concerned with their safety and the safety of their family and loved ones.
Athena can be contacted at Athena@protectselfdefence.co.nz
Website: http://www.protectselfdefence.co.nz/
SELF DEFENSE VANCOUVER/RICHMOND BC
Make a quick list of about 7 things that you believe are negative about you.
Once you’ve finished your list, take some time and go over it and then ask yourself the following questions:
Could it be possible that some of these beliefs might be untrue?
If this thought that’s making me suffer isn’t true, why am I hanging on to it?
And if I let it go, what would my life be like with out it?
Repeat for every item on your list and enjoy the journey to your True Self!
*For a deeper practice of seeing truth in your life, I highly recommend “The Work” of Byron Katie
SELF DEFENSE VANCOUVER/RICHMOND BC
Sonia Aslam Oct 30, 2011 09:06:46 AM
VANCOUVER (NEWS1130) – Two men in their 20s are in hospital with non-life threatening injuries after a double stabbing in Maple Ridge this morning. It happened around 3:45 a.m. at a house party on Gee Street.
No arrests have been made, but investigators are speaking with other people who were at the party.
This is the second stabbing in as many weeks in Maple Ridge. Less than two weeks ago, two teens were taken to hospital after being stabbed. A 19-year-old man was arrested in that case.
Anyone with information is asked to call Ridge Meadows RCMP at 604.463.6251 or Crime Stoppers at 1.800.222.8477.
First off, this isn’t a rant or me trying to come off as all knowing. This is my blog and me trying to make sense of the world around and within me. I’m not going to try to give anyone advice on what they could or should of done to prevent these stabbings from happening, as I don’t know all the facts, nor was I there. What we do know, is this was a party and it’s probably safe to assume that the usual elements were in attendance; ie) Alcohol, drugs, and egos. But again I wasn’t there. The question that keeps running through my head is this, “What is going so terribly wrong in someone’s life that they would want to stab another human being?” Stabbing or bludgeoning someone to death is a very intimate act of violence. Statistically in North America more people die by stabbings than shootings. Some of you might be thinking “If knives weren’t so readily available there wouldn’t be so many stabbings!”, but in reality knives, baseball bats, and guns aren’t doing the violence. It’s the individuals wielding them. Nor can we blame videos games, movies, t.v., secret societies, or government conspiracies. What we really need to look at is the source of violence as opposed to the tools used to deliver it. The root of all violence starts with the SELF and until we as a species come to that realization, all the laws, jails, and executions will never solve it. So if you really want to change the world around you, start by protesting the war within you and hope for peace.
SELF DEFENSE VANCOUVER/RICHMOND BC
