Geological Hazards
A natural hazard can be described as the threat of a potentially damaging process or phenomenon that occurs, or
has the potential to occur, in our physical environment. The hazard exists whether or not an event has happened.
A natural hazard becomes a natural disaster when an event occurs that causes injuries and damages beyond
society’s ability to cope.
A geological hazard is a natural hazard that has a geological or physiographic cause, trigger or effect. Canada is
vulnerable to a number of natural hazards including earthquakes, landslides, tsunamis, volcanic eruptions, floods
and melting permafrost.
Geological hazards can rarely be stopped, but careful land-use planning, robust building codes, engineered
mitigation structures, and personal preparedness can reduce the risk of loss.
• Earthquakes
• Landslides
• Tsunamis
Earthquakes
An earthquake is the rapid shaking of the Earth's surface that follows the sudden release
of energy within the Earth. Each year, more than 3500 earthquakes in or near Canada
are recorded and located by seismologists. Since most earthquakes are very small and
many occur in unpopulated areas, only about 50 earthquakes each year are reported by
the Canadian public. Most earthquakes that can be felt are too small or too remote to
cause damage. In the entire twentieth century, only about 20 earthquakes have caused
significant damage in this country.
Map of seismic hazard
Although seismologists are unable to predict when large earthquakes are going to occur,
they are able to look at geological evidence and historical patterns of seismic activity to
determine where future earthquakes are most likely to occur. This information is used to
develop seismic hazard models, which provide the design requirements for the National
Building Code of Canada. The building code helps to ensure that buildings are
constructed as earthquake resistant as possible. Individuals can help to reduce the effect
of an earthquake by checking with local emergency management organizations to
understand the risks in their region. Make a plan so that you know what to do in case of
an earthquake and prepare an emergency kit to help you and your family survive for 72
hours.
For more information:
Geological Survey of Canada: Earthquakes http://earthquakescanada.nrcan.gc.ca/
Atlas of Canada: Earthquakes
http://atlas.nrcan.gc.ca/site/english/maps/environment/naturalhazards/earthquakes
Public Safety Canada http://www.getprepared.gc.ca/_fl/rthqks-eng.pdf
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Landslides
Map of areas vulnerable to
landslides
A landslide is the downslope movement of sediment and rock. Landslides can be found
in any part of Canada, even in areas with very little relief. They happen in bedrock or in
loose sediment; on land or under water; may be large or small, rapid or slow, and
generally occur without warning. There is a wide variety of failure mechanisms and
triggering causes, and local geological and topographical conditions determine which
type of landslide may happen in a specific region. Some regions are particularly
susceptible to landsliding: steep slopes in the mountains; weak cretaceous bedrock
along valleys in the Prairies; and valleys eroded into fine-grained sediments in areas
once covered by glacial lakes and glacial seas.
Impact is greatest where landslide occurrence coincides with human activity. In the
historical period (taken to be post-1840), landslides in Canada have resulted in over 600
fatalities, including the destruction of several communities, and caused billions of dollars
in damage. The hazard presented by landslides involves not only failure of ground
beneath a structure and impact or burial by moving debris, but also secondary effects
such as landslide-dammed floods and landslide-generated waves. However, although
landslides will continue to occur annually, landslide risk in our lives can be reduced or
eliminated with proper planning and mitigation action.
For more information:
Geological Survey of Canada: Landslides http://gsc.nrcan.gc.ca/landslides/
Atlas of Canada: Landslides
http://atlas.nrcan.gc.ca/site/english/maps/environment/naturalhazards/landslides/1
Public Safety Canada http://www.getprepared.gc.ca
Tsunamis
A tsunami is a sea wave or series of waves produced by large disturbances of the sea floor
that are of relatively short duration. Such disturbances cause the water column to move
vertically and the resulting wave energy to spread outwards across the ocean surface at high
speed. Although tsunami occurrences in Canada are rare, they do occur and can cause major
damage and loss of life. Since the beginning of the twentieth century, there has been one
tsunami reported about every fifteen to twenty years in Canada.
Map of tsunami hazard
zones for Southwestern
British Columbia
Although it is impossible to prevent a tsunami, it is possible to estimate the tsunami risk for
coastal communities. Certain actions can be taken to lessen the effects of tsunamis (for
example, land-use controls such as zoning, relocation, and property acquisition). Other
means of protecting coastal areas at risk are emergency preparedness, dyking, barrier
construction, flood proofing, tsunami-resistant construction, warning systems including
signage, and public education.
For more information:
Atlas of Canada : Tsunamis
http://atlas.nrcan.gc.ca/site/english/maps/environment/naturalhazards/tsunami/1
Public Safety Canada http://www.getprepared.gc.ca
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Teacher Resources
These teacher resources provide a set of educational tools to raise awareness and heighten understanding of
geological hazards in Canada. The activities strive to support teachers in the successful delivery of Science and
Geography curriculum expectations while challenging students to relate the knowledge they have acquired to the
world outside their classroom.
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Disaster Maps
Disaster Timelines
PowerPoint Presentations
Lesson Plans
Disaster Maps
Page-size maps, showing Canadian disasters. Events are consecutively numbered by date; compatible with the
disaster timelines.
The earthquakes map shows the epicentre and the area of strong shaking for
• Earthquake [PDF]
Canadian earthquake disasters as well as for earthquakes that caused significant damage, were widely felt,
or were scientifically significant.
The landslides map shows Canadian landslide disasters that have caused 5-19, 20-49,
• Landslides [PDF]
and 50 or more fatalities.
Disaster Timelines
Timelines are presented as a graphic and as a list. The graphic depiction spreads over 2 pages. Information
includes date, location and impact. Events are consecutively numbered by date; compatible with the Disaster Maps.
• Earthquakes timeline: graphic [PDF], list [PDF] Canadian earthquakes of magnitude ≥5 that have had
significant impact.
Canadian landslides with ≥ 5 fatalities.
• Landslides timeline: graphic [PDF], list [PDF]
Tsunami events that have impacted Canada.
• Tsunamis timeline: list [PDF]
PowerPoint Presentations
The PowerPoint Presentations are accompanied by notes for the teacher.
• Earthquakes [PPT], Accompanying notes_Earthquakes [PDF] An introduction to plate tectonics and
earthquakes, including seismic waves, magnitude and intensity, the impacts, the 2010 Haitian and Chilean
earthquake examples, earthquakes in Canada, and how you can increase your personal preparedness.
• Landslides in Canada [PPT], Accompanying notes_Landslides in Canada [PDF] An introduction to
Canadian landslides including landslide types and characteristics, where they occur in Canada and why, the
impacts, disaster cases, and how you can increase your personal preparedness.
Lesson Plans
The following lesson plans offer a general introduction to the geological hazard, with a focus on Canadian
examples, for elementary and secondary school classes. Each lesson contains teaching notes (with answers),
maps and diagrams suitable for overhead projection, and student activities and worksheets.
• Earthquakes
• Landslides
• Tsunamis
Earthquakes
Description: A group of lesson plans offering a general introduction to earthquakes, including instructions for
teachers, teaching notes, exercises, word games, student research activities, damage assessments, and creative
writing tasks, with an emphasis on Canadian examples. Assorted grade levels.
An introduction to earthquakes for junior elementary students, including
1. Introduction to Earthquakes [PDF]
questions for class discussion, easy demonstrations, map analysis, and finishing with an earthquake
safety drill. Grades 3 to 5.
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2. Creative Essay [PDF]
Students write a ‘newspaper article’ describing an earthquake, written as if they were
there at the time of the event. Grades 3 to 5.
3. Introduction to Earthquakes [PDF]
A teacher-led lesson introducing earthquakes, including cause, seismic
waves, magnitude and intensity, and where they commonly occur. The lesson involves classroom
discussion, map analysis and a brief lab demonstration. Grades 7 to 9.
4. Earthquake Vocabulary Game [PDF]
Crossword puzzle, using earthquake terminology. Grades 7 to 9.
5. Design an Informative Brochure on Earthquakes and Safety [PDF]
Students create a brochure about
earthquakes, focusing on advice on how to increase personal safety. Grades 6 to 8.
6. Earthquakes in Canada [PDF]
A student research activity that explores the Earthquakes Canada website to
answer questions about Canadian and local earthquakes. Grades 7 to 12.
7. Locate the Earthquake Exercise [PDF]
Students learn to read a seismogram and calculate the epicentre of a
Canadian earthquake. Teachers can choose a seismogram package from eastern or western Canada.
Grades 7 to 12.
Independent reading and quiz. Students will read about earthquakes in Canada and
8. Earthquake Quiz [PDF]
then complete a quiz of true or false, or multiple choice questions. Grades 9 to12.
9. Earthquake Damage and Earthquake Preparedness [PDF]
A student research activity on earthquake
hazards and ways to reduce risk, culminating in group presentations to the class. Grades 9 to12.
Landslides
Description: A group of lesson plans offering a general introduction to landslides, including instructions for
teachers, teaching notes, lab demonstration, word games, student research activities, damage assessments, and
creative writing tasks, with an emphasis on Canadian examples. Assorted grade levels.
Teaching lesson using the Landslides in Canada PowerPoint presentation
1. Introduction to Landslides [PDF]
and accompanying notes. Grades 7 to 12.
2. The Frank Slide [PDF]
A junior elementary school activity (Grades 3 to 5) including a word search puzzle, a
map exercise, a classroom discussion, and a creative writing assignment on the historic Frank Slide,
the worst landslide disaster in Canada.
This lab demonstration is an easy and fun way to effectively produce a model
3. Make a Debris Flow [PDF]
debris flow landslide in the classroom. It can be used once as a simple demonstration or can become
an experiment comparing the results of different slope angles and different sediment textures. Suitable
for all grade levels.
This lesson consists of a presentation of how and why
4. Landslides in Eastern Canada − Earthflows [PDF]
landslides occur in sensitive clays of eastern Canada, followed by a choice of activities where students
can complete a vocabulary game, label a diagram of an earthflow, or identify the zone at risk of
landslides and decide where to locate a new hospital. Grades 7 to 9.
13 multiple choice or true/false questions on landslides in Canada for intermediate
5a. Landslide Quiz [PDF]
level students - Grades 7 to 9.
5b. Landslide Quiz [PDF]
12.
20 multiple choice or true/false questions on landslides in Canada for Grades 11 and
This activity teaches students to use a database to
6. Landslides in Canada − History of Disasters [PDF]
graph and analyze landslide disasters in Canada. It is followed by a classroom discussion. Grades 7 to
12.
This lesson includes map interpretation, topographic cross-sections, and discussion
7. Prairie Landslides [PDF]
of landslides along river valleys in the Prairies. Grades 7 to 12.
8. Debris Flows in British Columbia [PDF]
Students discover the relationship between weather conditions and
landslides by graphing and analyzing precipitation and runoff data prior to historic debris flow
landslides. This lesson could be used independently, or could follow the lab demonstration to model a
debris flow. Grades 11 and 12.
A teaching lesson about the landslide potential of the sensitive marine
9. Landslides in Eastern Canada [PDF]
clay (Leda Clay) of eastern Canada and a student activity. Students calculate the depth of potential
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failure along a river using real data. Using geological logs obtained from borehole coring, students
evaluate landslide hazard along a fictional river valley, determining the most hazardous and the safest
areas. Grades 11 and 12.
A classroom discussion focusing on reducing risk from landslides –
10. Reducing Risk from Landslides [PDF]
minimising personal risk and how communities reduce risk. Grades 9 to 12.
Tsunamis
Description: A group of lesson plans offering a general introduction to tsunamis, with an emphasis on tsunami
hazard along Canadian coasts. Lessons include teaching notes (with answers), lab demonstrations, maps and
diagrams suitable for overhead projection, damage assessments, emergency preparedness and student research
activities. The basics are taught in lessons 1or 7; the other activities are optional. For senior elementary and
secondary school.
A teaching lesson, including facts, explanations, vocabulary, diagrams
1.Introduction to Tsunamis [PDF]
suitable for overhead projection, and links to on-line resources. This activity provides the background for
the following activities, which are optional. Grades 6 to 8.
2. Tsunami Demonstration [PDF]
A short lab demonstration of tsunami waves. Grades 6 to 8.
3. Tsunami vocabulary [PDF] A crossword puzzle, word match game, and diagram exercise, to help students
learn tsunami terminology. Games may also be used as a test quiz. Grades 6 to 8.
4. Creative essay [PDF] A ‘newspaper article’ about either the Grand Banks or the Port Alberni tsunami
disaster, written as if they were there at the time of the event. Grades 6 to 8.
5. Tsunami Damages [PDF] Students assess the possible damages that might occur if a tsunami struck a
Canadian community of their choice. Grades 6 to 8.
6. Design a Tsunami Brochure [PDF] Students design and create a brochure about tsunamis, including advice
on increasing personal safety. Grades 6 to 8.
7. Introduction to Tsunamis [PDF] An introduction to tsunami waves and tsunami hazard in Canada, followed
by a student activity involving calculations of wave velocity, amplitude and travel time and explanation of
the results. Grades 9 to 12.
8. Create a Tsunami Model [PDF] A hands-on lab experiment, designed and conducted by students, to
generate and measure tsunami waves and prepare a scientific report. This is followed by a classroom
demonstration and discussion. Grades 9 to 12 (adaptable to Grades 6 to 8).
A mapping and database activity that
9. Exploring the Damages of the 1929 Grand Banks Tsunami [PDF]
explores the damages associated with the Grand Banks Tsunami that struck Newfoundland in 1929.
Grades 9 to 12.
10. Tsunami Warning System [PDF] Introduction to tsunami warnings, followed by a hands-on activity to
calculate velocity, amplitude and travel time of an earthquake-induced tsunami and preparation of a
tsunami warning notice. The lab is written for Prince Rupert but it can be easily changed to any coastal
community in British Columbia. Grades 9 to 12.
11. Emergency Preparedness Plan [PDF]
for Port Alberni. Grades 9 to 12.
Students research and create an emergency preparedness plan
12. Design an Informative Brochure on Tsunamis and Safety [PDF]
Students create a brochure about
tsunamis, including advice on how to increase personal safety. Grades 9 to 12.
13. Tsunami vocabulary crossword puzzle [PDF]
terminology. Grades 9 to 12.
14. Tsunami Quiz [PDF]
A crossword puzzle to help students to learn tsunami
Twenty multiple choice or true/false questions on tsunamis. Grades 9 to 12.
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Natural Resources Canada
Earthquakes in Canada
Accompanying Notes to “Shake It Up!”
J.M. Aylsworth
Geological Survey of Canada, Natural Resources Canada
Table of Contents
slide #
2–6
7–9
10 – 13
14 – 20
21 – 27
28 – 31
32 – 38
39 – 47
48 – 57
Earthquakes – Where, Why, How?
Earthquake Waves
Magnitude
Intensity & Impact
Recent Disasters - Haiti
Recent Disasters – Chile
Recent Disasters – Japan – Tsunami
Could it happen in Canada?
Personal Safety
Slide 2
Where do earthquakes happen?
• Earthquakes occur all over the world; however, a significant trend is obvious.
• Ninety-five percent of the world's earthquakes occur on active faults that form the boundaries of
the major tectonic plates of the Earth.
• The "Ring of Fire", circling the Pacific Ocean, and including Canada's west coast, is one of the
most active areas of earthquake and volcanic activity in the world.
Slide 3
Tectonic Plates
• The earth's outermost layer of crust and upper mantle is fragmented into a number of “tectonic
plates”.
• 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 cm per year.
• 95% of earthquakes occur on active faults that form the boundaries of the major tectonic plates of
the Earth.
What causes earthquakes?
• Earthquakes are the result of a sudden release of energy when rocks under stress slide abruptly
past one another along a break (fault) in the Earth's crust. Earthquakes are caused by the slow
deformation of the outer, brittle portions of tectonic plates. 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.
Slide 4
Movement of tectonic plates
The arrows on the map indicate the direction of plate movement.
There are 3 types of movement:
1. Divergent: Plates move away from each other along a zone of upwelling convection. E.g. MidAtlantic Ridge
2. Convergent: Plates move towards each other, causing one plate to override the other one,
forcing it to descend (‘subduct’) towards the interior of the Earth and melt back into the mantle.
E.g. Juan de Fuca Plate is subducting beneath the North American Plate.
3. Transform: Plates move in opposing directions past each other.
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Natural Resources Canada
Slide 6
What happens?
• The location within the Earth where the break or rupture occurs is called the FOCUS.
• The EPICENTRE is the location on the Earth’s surface directly above the focus.
• A fault is a zone of fractures or breaks in rocks where movements occur. Some faults may reach
the surface and, in a large earthquake, displacements of the ground may sometimes be observed
along the fault at the surface.
• Earthquake waves radiate outwards from the focus. What we feel during an earthquake is the
vibration of these waves on the surface.
Slide 7
What are earthquake (seismic) waves?
• During an earthquake, seismic waves are the vibrations that are initiated by fracturing of the Earth's
crust and radiate outward from the point of fracture.
• There are several different kinds of seismic waves, and they all move in different ways:
1. Body waves: These can travel through the interior of the earth. P-waves and S-waves are
body waves.
• The P-wave can move through solid rock or liquid.
• The S-wave can only move through solid rock, not through any liquid medium. It is this
property of S-waves that led seismologists to conclude that the Earth's outer core is a
liquid.
2. Surface waves: These are created when body waves reach the surface. They move only over
the surface of the Earth, like ripples on water. Rayleigh and Love waves are surface waves.
Slide 8
Seismic Waves
• Body Waves
1. The P-wave (primary or compressional) wave is the fastest seismic wave, and, the first to
'arrive' at a seismic station. The P-wave can move through solid rock or liquid. It moves by
pushing and pulling the medium that it moves through, (just like sound waves push and pull the
air.) Subjected to a P-wave, particles move in the same direction in which the wave is moving (the
direction in which the energy is traveling.) Usually people can only feel the bump and rattle of
these waves.
2. S-WAVES - The S-wave or secondary wave is the second wave you feel in an earthquake. The
S-wave is slower than a P-wave and can only move through solid rock, not through any liquid
medium. S-waves move rock particles up and down, perpendicular to the direction that the wave
is traveling.
• Surface waves
Surface waves are restricted to the Earth’s surface and do not pass through the interior of the Earth.
1. The Love wave is the fastest surface wave and moves the ground from side-to-side. Confined to
the surface of the crust, Love waves produce entirely horizontal motion.
2. A Rayleigh wave rolls along the ground just like a wave rolls across a lake or an ocean. Because
it rolls, it moves the ground up and down, and side-to-side in the same direction that the wave is
moving. Most of the shaking felt from a large earthquake is due to the Rayleigh wave, which can
be much larger than the other waves.
Slide 9
Seismograms
• Earthquake vibrations are recorded on seismographs and shown on seismograms. Because each
type of wave travels at a distinctive velocity, the first arrival of each wave can be distinguished on the
seismogram.
• Seismograms are used to locate the epicentre and calculate the magnitude.
Slide 10
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Natural Resources Canada
Seismograms are used to:
Locating the Epicentre
Because the velocity of P and S-waves are known, seismologists can use the difference in their
arrival times at a recording station to calculate the distance of that station from the epicentre. With
values from 3 different recording stations, the location of the epicentre can be determined, as shown
on this map. Circles representing the calculated distance to the epicentre from the station are drawn
on a map. The epicentre lies at the intersection of the 3 circles.
Slide 11
Magnitude & Amplitude
• Seismograms are also used to calculate the magnitude of an earthquake.
• By measuring the time interval between the arrivals of the P and S wave groups seismologists are
able to calculate the distance between the seismograph and the origin of the earthquake. Magnitude
is then derived from the amplitude of the waves on the seismogram and the distance of the
earthquake from the seismograph.
Slide 12
Magnitude
• Magnitude is a unique number that represents the strength of an earthquake at its epicentre.
• The seismogram diagrams on the right can be used to illustrate a logarithmic scale. Each is 10 times
greater than the previous.
• Stress to the students that, when talking about an earthquake being a (e.g.) 5 or a 6 on the
magnitude scale, there is a great difference between a magnitude 5 earthquake and a magnitude 6
earthquake and this will be apparent in the damages associated with each.
• The magnitude of an earthquake is proportional to the length of the rupture zone.
Slide 13
Magnitude
• Each year there are thousands of earthquakes of magnitude 1 to 3.5, but their vibrations are rarely
felt. Large magnitude, damaging earthquakes occur much less frequently.
• The largest earthquake ever recorded was a magnitude 9.5 in Chile in 1960.
• Canada’s largest recorded earthquake (magnitude 8.1) occurred along the Queen Charlotte Fault in
BC in 1949.
• Canada’s largest earthquake was a magnitude 9.0, Cascadia subduction zone earthquake
offshore of Vancouver Island, Washington and Oregon on Jan. 26, 1700. This event was widely
recorded in native oral accounts and confirmed by geological evidence for both surface subsidence
and a tsunami along the outer coast. The date was confirmed by a tsunami record in Japan of a
tsunami with an unknown source (no earthquake was felt).
Slide 14
Intensity
• Earthquakes are measured in two ways:
1. Magnitude is a measure of the amount of fault movement at the source of the quake.
2. Intensity is what we feel when an earthquake occurs and it varies from place to place.
• There is only one magnitude but there can be many different intensities, depending on how far we are
from the source and our local geological conditions.
• Intensity is measured on the Modified Mercalli Intensity Scale.
Slide 15
Intensity
• The Modified Mercalli Intensity Scale is based on personal reports of what was felt and observed at
each location. Intensity is a more useful way of evaluating the impact of an earthquake.
Slide 16
Intensity
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Natural Resources Canada
•
Intensity values from many reports can be plotted on a map to illustrate the earthquake’s impact over
a large region.
(Note : the colour scale on these images is slightly different than the one on the previous slide.)
Slide 18
Amplification effects
• Shaking intensity depends on
1. the size of the earthquake (magnitude),
2. the distance from the epicentre, and
3. the underlying geology. Soft soils (sand, silt and clay) experience longer and greater shaking
than do bedrock or stiff soils (hard glacial till). When the earthquake waves pass from stiff soil
to soft soil, their velocity decreases dramatically. When velocity decreases, wave amplitude
must increase, resulting in stronger shaking at the surface. The effect is augmented by
resonance effects – the wave reaches the surface and returns, only to bounce back off the
impedance layer of stiff soil, creating a resonance effect between the surface and impedance
layer, and resulting in longer shaking at the surface.
Slide 19
Impact:
• Many earthquakes are not felt or, although felt, cause no damage.
• In strong earthquakes buildings and bridges may be damaged or collapse.
• Even when no structural damage occurs to buildings, falling objects present a major hazard inside a
building.
Slide 20
Impact:
• Tsunamis can follow a large earthquake if there has been a significant ground movement on the
ocean floor.
• Unusual retreat of the sea often precedes the arrival of the tsunami wave.
• In the deep ocean, tsunami waves are barely distinguishable, with a very long wavelength and small
wave amplitude. As it approaches shore, the wave slows, wavelength decreases and amplitude
greatly increases, causing the wall of rushing water at the shore.
• Although rare, Canada has experienced tsunamis that were triggered by earthquakes and landslides.
Slide 22
Recent Earthquake Disasters – Haiti, 2010
• A major disaster – the fourth deadliest earthquake in world history - ~230,000 deaths
• Source of information : IRIS http://www.iris.washington.edu/hq/
Slide 23
Haiti – Regional Tectonics
• Motion between the Caribbean and North American plates occurs along two major east-west
trending, strike-slip fault systems.
• The earthquake was a left-lateral strike slip faulting on the southern fault system. This fault system
moves about 7 mm/yr.
Slide 24
Haiti – History
• The dots locate epicentres of earthquakes that occurred in the last 20 years. (Colours indicate depth
of focus.)
• Most earthquakes are associated with the northern fault system.
• The January 12, 2010 earthquake occurred in the southern fault system.
Slide 25
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Natural Resources Canada
Haiti - Shaking intensity map
Why was the Haiti earthquake only lightly felt in neighbouring countries (Dominican Republic,
Cuba)?
• The areas subjected to extreme (red) to strong (yellow) shaking are restricted to a small region
because only a relatively short length (70 km) of the fault actually ruptured.
Slide 26
Haiti – Aftershock
• Aftershock: An earthquake that occurs after a "mainshock" (or larger earthquake).
• Aftershocks occur in the same general region as the "mainshock" and result from readjustments of
stress at places along the fault zone. Depending on the size, and depth of the earthquake,
aftershocks may occur for many months after the mainshock. However, both the size, and the rate of
aftershock activity dies off quickly with time.
Slide 27
Haiti – Impact
• In the top 10 list of deadliest earthquakes in world history.
• About 230,000 deaths. Widespread destruction in Southern Haiti.
• Damages were so great because:
1. A densely populated city, Port-au-Prince, is close to the epicentre and experienced an
intensity of 8+.
2. Many buildings were poorly constructed and collapsed.
Slide 28
Chile, 2010 - A “Great” Earthquake
• Seismologists estimate that the earthquake was so powerful that it may have shortened the length of
the day by 1.26 microseconds and moved the Earth's figure axis by 8 cm or 2.7 milliarcseconds.
• Preliminary measurements show that the entire South American Plate moved abruptly westward
during the quake. Researchers from Ohio State University and other institutions have found, using
GPS, that the earthquake shifted Santiago (28 cm) to the west-southwest and moved Concepción at
least 3 meters to the west. The earthquake also shifted other parts of South America. For example, it
moved Buenos Aires, Argentina, about 2.5 cm to the west. (Source: Wikipedia)
• The source for much of this information on Chile earthquake section is taken from a “Teachable
moment” powerpoint prepared by IRIS (Incorporated Research Institutes for Seismology) at this
url:http://www.iris.edu/hq/retm/event/962
Slide 29
Chile - Tectonics
• The earthquake occurred as thrust-faulting on the interface between the Nazca and South American
plates, with the Nazca plate moving landward and downward below the South American plate. This is
a subduction zone.
• The red star on the map shows the epicentre of the earthquake while the arrows show the direction of
motion of the Nazca Plate toward the South American Plate.
• At the location of this earthquake, the two plates are converging at a rate of about 8 cm/yr.
• The rupture extended about 700 km along the length of the fault, and from the Earth’s surface to
depths of over 50 km.
• The largest amounts of rupture occurred in the first 60 seconds but smaller displacements continued
for up to 200 seconds after the start of the earthquake.
Slide 30
Chile – History
• The length of the 2010 rupture was ~700 km, ten times greater than the Haitian rupture length. It
occurred just north of the 1960 rupture which produced the strongest quake ever measured.
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Natural Resources Canada
•
History: The 1960 Valdivia Quake (magnitude 9.5) was the strongest quake ever measured in
the world.
• The 1960 earthquake occurred beneath the Pacific Ocean off the coast of Chile. Ground motion
from this earthquake destroyed and damaged many buildings, leaving about 2,000,000 people
homeless. Because it occurred in mid- afternoon and was preceded by a powerful foreshock,
people were frightened from their buildings, placing them outside when the main earthquake
occurred. Casualty estimates for this earthquake, range as high as 6000 people.
• It generated a series of tsunamis. These waves swept over areas of coastal Chile moments after
the earthquake occurred, destroying buildings and drowning many people. The tsunami impacted
the entire Pacific Ocean; fatalities occurred as far away as the Philippines, Japan and Hawaii.
Slide 31
Chile – Impact 2010
•
Building destruction was not as widespread in Chile as in Haiti because Chile builds to the
earthquake standards of a national building code. Hence there were fewer fatalities, although the
shaking was more severe in Chile.
•
Note that masonry falling off the facade of buildings presents a hazard.
•
The earthquake triggered a tsunami which devastated several coastal towns in south-central Chile. A
2.34 m high tsunami wave hit Talcahuano, a port city near Concepción. The tsunami caused serious
damage to port facilities and lifted boats out of the water. In the fishing town of Dichato, which has
7,000 residents, it was the third tsunami wave that ended up being the most damaging.
•
Tsunami warnings were issued in 53 countries. Minor tsunami damage occurred in the San Diego
area of California and in the Tōhoku region of Japan.
Slide 32
Japan 2011
•
Magnitude 9 earthquake, one of the largest in Japanese history, followed by a catastrophic tsunami.
•
See this URL for more information on the earthquake and tsunami in Japan, March 2011:
•
http://www.iris.edu/hq/retm/event/1328
Slide 39
Could it happen in Canada?
Slide 40
Yes, Canada has earthquakes !
•
Map shows the earthquakes that occurred over a 30 day period. (A current update of this map can
be found at Earthquakes Canada at http://earthquakescanada.nrcan.gc.ca/index-eng.php )
Slide 41
Canada
•
About 4000 earthquakes per year occur in or near Canada (~11 per day!), but only 50-55 are
reported as ‘felt’.
•
The majority of these felt earthquakes are too small to cause any damage.
•
Since 1900, about 20 earthquakes have caused significant damage in Canada.
•
Canada’s largest recorded earthquake (magnitude 8.1) occurred along the Queen Charlotte Fault
in BC in 1949.
•
Canada’s largest earthquake was a magnitude 9.0, Cascadia subduction zone earthquake
offshore of Vancouver Island, Washington and Oregon on Jan. 26, 1700. This event was widely
recorded in native oral accounts and confirmed by geological evidence for both surface subsidence
and a tsunami along the outer coast. The date was confirmed by a tsunami record in Japan.
•
As seen on the map, earthquakes occur in specific zones. They are most frequent off the west coast.
They are very rare in the interior of Canada.
6
Natural Resources Canada
Slide 42
Where do most of the earthquakes happen in Canada?
1. Earthquakes along Canada’s west coast occur at or near the margins of slowly moving tectonic
plates. (Offshore B.C., SW Yukon, Richardson Mountains and Mackenzie Valley)
2. In Eastern Canada earthquakes are not at the edge of a tectonic plate. They are in regions of
crustal weakness. The slow movement of the North American Plate away from the Mid-Atlantic
Ridge may activate old zones of weakness and faults such as the St. Lawrence Valley.
3. In the Arctic, earthquakes also seem to be associated with plate margins and older geological
features, but may also be related to stresses produced as the land continues to rise following
melting of the heavy ice sheets from the last continental glaciation.
• Although a region may have earthquakes, human risk is slight if few people live there. The Southern
Cordillera and the St. Lawrence Lowlands have the greatest risk of earthquakes.
Slide 43
Significant* Earthquakes Affecting Canada
#
Date**
Magnitude
Description
1
1663, Feb. 5
M 7.0
Charlevoix-Kamouraska region, QC.
2
1700, Jan. 26
M 9.0
Cascadia subduction zone, offshore of Vancouver Island, Washington
and Oregon.
3
1732, Sept. 16
M 5.8
Near Montreal, QC.
4
1791, Dec. 6
M 6.0
Charlevoix-Kamouraska region, QC.
5
1860, Oct. 17
M 6.0
Charlevoix-Kamouraska region, QC.
6
1870, Oct. 20
M 6.5
Charlevoix-Kamouraska region, QC.
7
1899, Sept. 10
M 8.0
Yukon-Alaska border.
8
1904, Mar.21
M 5.9
Passamaquoddy Bay, NB.
9
1909, May 15
M 5.3
Near the Saskatchewan border in Montana.
10
1918, Feb. 4
M 6.0
Revelstoke, BC.
11
1918, Dec.6
M 6.9
Vancouver Island, BC.
12
1920, Jan. 23
M 5.5
Gulf Islands, BC.
13
1925, Feb. 28
M 6.2
Charlevoix-Kamouraska region, QC.
14
1929, May 26
M 7.0
Just south of Haida Gwaii, BC.
15
1929, Nov. 18
M 7.2
Atlantic Ocean, south of NL. Tsunami.
16
1933, Nov. 20
M 7.3
Baffin Bay, Nunavut.
17
1935, Nov. 1
M 6.1
Quebec-Ontario border.
18
1944, Sept. 5
M 5.6
Eastern Ontario-New York border.
19
1946, Jun. 23
M 7.3
Central Vancouver Island, BC.
20
1949, Aug. 21
M 8.1
Off Haida Gwaii, BC. Canada’s largest historical earthquake.
21
1964, Mar. 27
M 9.2
Near Anchorage, Alaska. Tsunami.
22
1970, Jun. 24
M 7.4
South of Haida Gwaii BC.
7
Natural Resources Canada
23
1979, Feb. 28
M 7.5
Southern Yukon-Alaska border.
24
1982, Jan. 9
M 5.8
First of two moderate earthquakes, Miramichi Highlands, NB.
25
1985, Dec. 22
M 6.9
Nahanni region, NWT.
26
1988, Nov. 25
M 5.9
Saguenay region, QC.
27
1989, Dec. 25
M 6.3
Ungava Peninsula, QC.
28
2010, Jun. 23
M 5.0
Val-des-Bois, QC.
*Significant events are defined as magnitude greater than or equal to 6, or widely felt, or causing significant damage from shaking or
tsunami waves, or it is scientifically interesting.
** Date is the local date.
Slide 44
West Coast
• Cascadia Subduction zone. Juan de Fuca plate is subducting beneath the North American plate.
• Also associated with volcanic activity
Slide 45
West Coast : The Cascadia Subduction Earthquake, 1700
•
At 9PM on January 26, 1700 one of the world's largest earthquakes occurred along the west coast of
North America. The undersea Cascadia thrust fault ruptured along a 1000 km length, from mid
Vancouver Island to northern California in a great earthquake, producing tremendous shaking and a
huge tsunami that swept across the Pacific. The Cascadia fault is the boundary between two of the
Earth's tectonic plates: the smaller offshore Juan de Fuca plate that is sliding under the much larger
North American plate.
• The earthquake shaking collapsed houses of the Cowichan people on Vancouver Island and caused
numerous landslides. The shaking was so violent that people could not stand and so prolonged that it
made them sick. On the west coast of Vancouver Island, the tsunami completely destroyed the winter
village of the Pachena Bay people with no survivors. These events are recorded in the oral traditions
of the First Nations people on Vancouver Island. The tsunami swept across the Pacific also causing
destruction along the Pacific coast of Japan. It is the accurate descriptions of the tsunami and the
accurate time keeping by the Japanese that allows us to confidently know the size and exact time of
this great earthquake.
• The earthquake also left unmistakeable signatures in the geological record as the outer coastal
regions subsided and drowned coastal marshlands and forests that were subsequently covered with
younger sediments. The recognition of definitive signatures in the geological record tells us the
January 26, 1700 event was not a unique event, but has repeated many times at irregular intervals of
hundreds of years. Geological evidence indicates that 13 great earthquakes have occurred in the last
6000 years.
• We now know that a similar offshore event will happen sometime in the future and that it represents a
considerable hazard to those who live in southwest B.C. However, because the fault is offshore, it is
not the greatest earthquake hazard faced by major west coast cities. In the interval between great
earthquakes, the tectonic plates become stuck together, yet continue to move towards each other.
This causes tremendous strain and deformation of the Earth's crust in the coastal region and causes
ongoing earthquake activity. This is the situation that we are in now. Some onshore earthquakes can
be quite large (there have been four magnitude 7+ earthquakes in the past 130 years in southwest
B.C. and northern Washington State). Because these inland earthquakes can be much closer to our
urban areas and occur more frequently, they represent the greatest earthquake hazard. An inland
magnitude 6.9 earthquake in 1995 in a similar geological setting beneath Kobe, Japan caused in
excess of $200 billion damage.
Slide 47
East Coast : The 1929 Magnitude 7.2 "Grand Banks" earthquake and tsunami
8
Natural Resources Canada
•
•
•
•
On November 18, 1929 at 5:02 pm Newfoundland time, a major earthquake occurred approximately
250 km south of Newfoundland along the southern edge of the Grand Banks. This magnitude 7.2
tremor was felt as far away as New York and Montreal. On land, damage due to earthquake
vibrations was limited to Cape Breton Island where chimneys were overthrown or cracked and where
some highways were blocked by minor landslides. A few aftershocks (one as large as magnitude 6)
were felt in Nova Scotia and Newfoundland but caused no damage.
The earthquake triggered a large submarine landslide (an estimated volume of 200 cubic
kilometres of material was moved on the Laurentian slope) which ruptured 12 transatlantic cables in
multiple places (locations of cable breaks can be seen as small circles on the map). The huge
landslide generated a tsunami (a large induced sea wave). The tsunami was recorded along the
eastern seaboard as far south as South Carolina and across the Atlantic Ocean in Portugal.
Approximately 2 1/2 hours after the earthquake the tsunami struck the southern end of the Burin
Peninsula in Newfoundland as three main pulses, causing local sea levels to rise between 2 and 7
metres. At the heads of several of the long narrow bays on the Burin Peninsula the momentum of the
tsunami carried water as high as 13 metres. This giant sea wave claimed a total of 28 lives – 27
drowned on the Burin peninsula and a young girl never recovered from her injuries and died in 1933.
More information:
http://earthquakescanada.nrcan.gc.ca/histor/20th-eme/1929/1929-eng.php
Slide 48
What Can We Do?
• The National Building Code – Canadian buildings are designed to withstand earthquake shaking.
However old buildings may not meet the code – many have been retrofitted (fixed up to code).
Slide 49
What should you do during an earthquake?
• If you are indoors, stay there.
Do not run outside: you could be hit by flying debris or bits of glass. Take cover under, and hold on to
a sturdy desk, a table, or a bed. Avoid windows and tall furniture.
• If you are outdoors, stay there.
Keep away from power lines and buildings. (House chimneys are likely to topple during a strong
earthquake).
• If you are in a vehicle, stop and park away from buildings, bridges and overpasses.
• If you are in a low coastal area, go to high ground.
Slides 51 to 57
Personal Safety
• These slides provide more detailed information on what to do during and after an earthquake.
Source : http://www.getprepared.gc.ca/knw/ris/eq-eng.aspx#a4
9
Timeline: Significant* Earthquakes Affecting Canada
#
Date**
Magnitude
Description
1
1663, Feb. 5
M 7.0
Charlevoix-Kamouraska region, QC. Damage to buildings in Quebec
City, Trois-Rivières and Montreal. Large landslides in St. Lawrence,
Batiscan and St-Maurice valleys.
2
1700, Jan. 26
M 9.0
Cascadia subduction zone, offshore of Vancouver Island, Washington
and Oregon. Occured prior to European contact but widely recorded
in native oral accounts and by geological evidence for both subsidence
and a tsunami along the outer coast; confirmed by tsunami records in
Japan. Oral accounts describe many tsunami deaths.
3
1732, Sept. 16
M 5.8
Near Montreal, QC. Widely felt. About 300 houses damaged in the city.
No injuries.
4
1791, Dec. 6
M 6.0
Charlevoix-Kamouraska region, QC. Widely felt. Some damage at
Baie-Saint-Paul and Les Éboulements.
5
1860, Oct. 17
M 6.0
Charlevoix-Kamouraska region, QC. Widely felt. Minor damage at
Rivière-Ouelle, Baie-Saint-Paul and La Malbaie.
6
1870, Oct. 20
M 6.5
Charlevoix-Kamouraska region, QC. Widely felt. Minor damage at
Baie-Saint-Paul, Les Éboulements and Quebec City.
7
1899, Sept. 10
M 8.0
Yukon-Alaska border. Three great earthquakes (M 7.4 to 8) in this
region in the space of eight days. Felt in parts of northern British
Columbia and southern Yukon.
8
1904, Mar.21
M 5.9
Passamaquoddy Bay, NB. Strong earthquake felt throughout the
Maritimes, the St. Lawrence Lowlands and New England.
9
1909, May 15
M 5.3
Near the Saskatchewan border in Montana. The largest historical
earthquake in the prairie region of Canada and US, felt from Alberta to
Ontario.
10
1918, Feb. 4
M 6.0
Revelstoke, BC. Felt in BC interior.
11
1918, Dec.6
M 6.9
Vancouver Island, BC. Felt all over Vancouver Island, in Vancouver,
as far east as Kelowna BC, and in northern Washington State. Some
damage to Estevan Point lighthouse and a wharf in Ucluelet.
12
1920, Jan. 23
M 5.5
Gulf Islands, BC: Fallen plaster, broken china in Victoria. In Brentwood
Bay, the concrete chimney and wall of an electric power station were
cracked. In Vancouver a few bricks fell from the tops of chimneys.
13
1925, Feb. 28
M 6.2
Charlevoix-Kamouraska region, QC. Felt over most of eastern Canada
and northeastern US. Considerable damage to unreinforced masonry
(chimneys, walls) along the St. Lawrence River near the epicentre and
some damage at Quebec City (port facilities), Trois-Rivières and
Shawinigan. Six deaths due to heart attacks are ascribed to this
earthquake.
Geological Survey of Canada
Natural Resources Canada
14
1929, May 26
M 7.0
Just south of Haida Gwaii, BC. Felt as far north as Ketchikan, Alaska,
and to the east as far as Terrace, BC. On Haida Gwaii houses shook
violently, people were thrown to the ground, dishes were broken and
some clocks stopped.
15
1929, Nov. 18
M 7.2
Atlantic Ocean, south of NL. Felt over a wide area of eastern North
America. A massive landslide off the continental slope triggered an
immense tsunami that killed 27 people on the Burin Peninsula, NL.
16
1933, Nov. 20
M 7.3
Baffin Bay, Nunavut. One of the largest earthquakes ever recorded
north of the Arctic Circle.
17
1935, Nov. 1
M 6.1
Quebec-Ontario border. Felt over much of eastern Canada. Minor
damage at Temiscaming, QC, and North Bay and Mattawa, ON. Three
hundred kilometres away from the epicentre the earthquake triggered
the failure of a railway embankment.
18
1944, Sept. 5
M 5.6
Eastern Ontario-New York border. Felt over most of eastern Ontario,
southern Quebec and New England. Damage at Cornwall, ON, and
Messina, NY.
19
1946, Jun. 23
M 7.3
Central Vancouver Island, BC. Felt as far away as Portland OR, and
Prince Rupert, BC. Largest historical earthquake on land in Canada.
Extensive damage along the east coast of Vancouver Island (VI) with
many landslides triggered on VI and the adjacent mainland. An
underwater landslide triggered a local tsunami at Deep Bay, one
person drowned.
20
1949, Aug. 21
M 8.1
Off Haida Gwaii, BC. Felt over a wide area of western North America.
Canada’s largest earthquake. Some damage on Haida Gwaii, cows
knocked off their feet.
21
1964, Mar. 27
M 9.2
Near Anchorage, Alaska. Widespread damage in Alaska. Felt strongly
in western Yukon. Serious damage from tsunami at Port Alberni, BC.
22
1970, Jun. 24
M 7.4
South of Haida Gwaii BC. Widely felt.
23
1979, Feb. 28
M 7.5
Southern Yukon-Alaska border. Felt strongly in Canada. Minor
property damage in the Yukon.
24
1982, Jan. 9
M 5.8
First of two moderate earthquakes, Miramichi Highlands, NB. Because
the epicentral area is unpopulated, damage was very slight: a few
hairline cracks but no structural damage in buildings up to 100 km
away. Followed by hundreds of aftershocks over several months.
25
1985, Dec. 22
M 6.9
Nahanni region, NWT. Widely felt in NWT, AB and BC. A smaller
event (M 6.6) in the same area on October 5, 1985 triggered a large
rock avalanche.
26
1988, Nov. 25
M 5.9
Saguenay region, QC. Felt in a 1,000-km radius from the epicentre.
Damage at Jonquière, Chicoutimi, La Baie, Quebec City and as far
away as Montreal.
27
1989, Dec. 25
M 6.3
Ungava Peninsula, QC. First earthquake in eastern North America
confirmed to have produced surface faulting. Weakly felt in some
northern QC communities.
28
2010, Jun. 23
M 5.0
Val-des-Bois, QC. Widely felt in a 700-km radius from the epicentre in
western Quebec. Triggered two landslides. Some damage in the
epicentral region and minor damage in Ottawa.
* Significant events are defined as magnitude greater than or equal to 6, or widely felt, or causing significant damage from
shaking or tsunami waves, or it is scientifically interesting. ** Date is the local date.
Geological Survey of Canada
Natural Resources Canada
Timeline of Major Earthquake Events in Canada
Installation of the first seismographs
in Canada
Time
3
2
1660
1700
5
4
1750
1800
6
7
1850
8
1900
10
11 12
9
1910
13
1920
1
2
3
4
5
7
8
9
10
13
1663
1700
1732
1791
1860
1899
1904
1909
1918
1925
Feb. 5
M 7.0
CharlevoixKamouraska
region, Que.
Damage to
buildings in
Quebec City,
Trois-Rivières
and Montreal.
Vast landslides
in St. Lawrence,
Batiscan and
St-Maurice
valleys.
Jan. 26
M 9.0
Cascadia
subduction zone,
offshore of
Vancouver Island,
Washington and
Oregon. Widely
recorded in native
oral accounts and
by geological
evidence for both
subsidence and a
tsunami along the
outer coast;
confirmed by a
tsunami record in
Japan. Extent of
damage unknown.
Sept. 16
M 5.8
Near Montreal,
Que.
Widely felt. About
300 houses
damaged in the
city. No injuries.
Dec. 6
M 6.0
CharlevoixKamouraska
region, Que.
Widely felt. Some
damage at BaieSaint-Paul and Les
Éboulements.
Oct. 17
M 6.0
CharlevoixKamouraska
region, Que .
Widely felt.
Minor
damage at
RivièreOuelle, BaieSaint-Paul
and La
Malbaie.
Sept.10
M 8.0
Yukon-Alaska
border.
Three great
earthquakes
(M 7.4 to 8) in
this region in
the space of
eight days.
Strong effects
experienced
in many parts
of northern
British
Columbia and
southern
Yukon.
Mar. 21
5.9
Passamaquoddy
Bay, NB.
Strong
earthquake felt
throughout the
Maritimes, the
St. Lawrence
Lowlands and
New England.
May 15
M 5.3
Near the
Saskatchewan
border in
Montana.
Largest historical
event in the
prairie region of
Canada.
Feb. 4
M 6.0
Near the
Saskatchewan
border in
Montana.
Largest historical
event in the
prairie region of
Canada.
Feb. 28
M 6.2
CharlevoixKamouraska
region, Que.
Widely felt.
Considerable
damage along
the St.
Lawrence River
near the
epicentre and
some damage
at Quebec City,
Trois-Rivières
and Shawinigan.
6
1870
Oct. 20
M 6.5
CharlevoixKamouraska
region, Que.
Widely felt.
Minor
damage at
Baie-SaintPaul, Les
Éboulements
and Quebec
City.
11
1918
Dec. 6
M 6.9
Vancouver
Island, B.C.
Widely felt.
Some minor
damage near
Estevan Point.
12
Significant events are defined as magnitude greater than or equal to 6, or widely felt, or
causing significant damage from shaking or tsunami waves, or it is scientifically
interesting. Date is the local date.
1920
Jan. 23
M 5.5
Gulf Islands,
B.C.
Fallen plaster
and broken china
in Victoria. Some
chimneys in
Vancouver
damaged
attach to page 2
1
1
Timeline of Major Earthquake Events in Canada
Time
14
15
16
17
1930
1950
21
1960
23
22
1970
25
24
26 27
1980
1990
28
2000
2010
16
17
18
20
21
22
23
25
27
28
1933
1935
1944
1949
1964
1970
1979
1985
1989
2010
Nov. 20
M 7.3
Baffin Bay,
Nunavut.
Largest
earthquake
ever known
north of the
Arctic Circle.
Nov. 1
M 6.1
QuebecOntario border.
Felt over much
of eastern
Canada. Minor
damage at
Temiscaming,
Que., and
North Bay and
Mattawa, Ont.
Sept. 5
M 5.6
Eastern
OntarioNew York
border.
Widely felt.
Damage at
Cornwall,
Ont., and
Messina,
N.Y.
Aug. 21
M 8.1
Off Haida Gwaii,
B.C.
Felt over a wide
area of western
North America.
Canada's largest
earthquake. Some
damage on Haida
Gwaii.
Mar. 27
M 9.2
Near Anchorage,
Alaska.
Widespread
damage in
Alaska. Felt
strongly in
western Yukon.
Serious damage
from tsunami at
Port Alberni, B.C.
Jun. 24
M 7.4
South of Haida
Gwaii, B.C.
Widely felt.
Feb. 28
M 7.5
Southern
Yukon-Alaska
border.
Felt strongly in
Canada. Minor
property
damage in the
Yukon.
Dec. 22
M 6.9
Nahanni
region, NWT.
Widely felt in
N.W.T., Alberta
and B.C. A
smaller event
(M 6.6) in the
same area two
months earlier
triggered a
large rock
avalanche.
Dec. 25
M 6.3
Ungava
Peninsula,
Que.
First
earthquake in
eastern North
America
confirmed to
have produced
surface
faulting.
June 23
M 5.0
Val-des-Bois,
Que.
Widely felt in a
700-km radius
from the
epicentre in
western
Quebec.
Triggered 2
landslides.
Some minor
structural
damage.
14
19
1929
1946
24
1988
May 26
M 7.0
Just south of Haida Gwaii,
B.C.
Damage on Haida Gwaii.
Jun. 23
M 7.3
Central Vancouver
Island, B.C.
Widely felt.
Extensive damage
along the east
coast of Vancouver
Island. Underwater
landslides
triggered a tsunami
at Comox, one
person drowned.
1982
Nov. 25
M 5.9
Saguenay
region, Que.
Felt in a 1,000km radius from
the epicentre.
Damage at
Jonquière,
Chicoutimi, La
Baie, Quebec
City and as far
away as
Montreal.
1929
attach to page 1
20
1940
15
2
18 19
Nov. 18
M 7.2
Atlantic Ocean, south of
Newfoundland.
Felt over a wide area of
eastern North America. A
massive landslide off the
continental slope triggered
an immense tsunami that
killed 27 people on the
Burin Peninsula, Nfld.
26
Jan. 9
M 5.8
First of two
moderate
earthquakes in
the Miramichi
Highlands, NB.
Slight damage,
followed by
100’s of
aftershocks
over several
months.
Natural Resources Canada 2011: Lesson Plan - Grades 7 to 9
Earthquake activity 3:
Introduction to Earthquakes
Description: A teacher-led lesson introducing senior elementary students to earthquakes, including
cause, seismic waves, magnitude and intensity, and where they commonly occur. The
lesson involves classroom discussion, map analysis and 2 brief demonstrations.
Materials:
Overheads:
1. Earthquakes in Canada map; 2. Tectonic Plates map; 3. Seismogram;
4. Magnitude Scale and 5. Modified Mercalli Intensity Scale
Brick, sandpaper, elastic cord
Teacher instructions and notes:
•
Preparation: The teacher may want to review information in advance on the following websites.
Geological Survey of Canada: http://earthquakescanada.nrcan.gc.ca
Atlas of Canada: http://atlas.nrcan.gc.ca/site/english/maps/environment/naturalhazards/earthquakes
•
Introduce the topic by asking a few questions to encourage student participation.
o
•
Have you ever felt an earthquake? What happened? Where were you when it happened?
Ask the class the following questions and lead them to the appropriate answer provided below. Class
should take notes.
1. What is an earthquake?
A sudden shaking of the ground.
2. What happens during an earthquake?
The ground trembles or shakes. Depending on the size of the earthquake, people may fall down;
buildings or bridges might collapse; it might even create a huge wave in the ocean called a tsunamis.
Ensure that they also understand that many events are so small that people do not even notice them,
although scientific instruments can still measure them. About 4000 earthquakes per year are located
in or near Canada, but only 50-55 are reported as ‘felt’. The majority of these felt earthquakes are too
small to cause any damage. In the 20th century, about 20 earthquakes have caused significant
damage in Canada. (Show overhead 1, the Earthquakes in Canada map)
3. What causes an earthquake?
An earthquake is the result of a sudden release of energy when rocks under stress slide abruptly past
one another along a break (fault) in the Earth's crust. 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. (Show overhead 2, the Tectonic Plates map.) 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 plate, 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.
Epicentre: The epicentre is the position on the surface of the Earth
directly above the location of the earthquake. The amount of ground
shaking generally decreases as you move away from epicentre.
J.M. Aylsworth, Geological Survey of Canada, Natural Resources Canada.
1
To illustrate the stick-slip action, use the following earthquake simulation demonstration:
Demonstration 1: Earthquake Simulation Model
(courtesy of Earthnet)
Purpose: to demonstrate the sudden rupture of a fault that produces an earthquake
Materials: 2 bricks
string and bungee cord
tray of water
paper and pen and Blu Tak
Procedure:
1. Put two bricks, one on top of the other, on a table.
2. Draw a bar across the paper and cut in half so that the bar is divided in
the middle. With Blu Tak, attach one half of the paper on the bottom brick
and the other half on the top brick so that the bar appears continuous.
3. Put a tray of water on top of the bricks.
4. Tie string around the top brick.
5. Hook the end of bungee cord onto the string and gently, but persistently,
pull the bungee cord until the top brick suddenly slides.
6. At the moment the brick slides, observe the waves that travel through the
water. The shock waves travel down the bungee cord in the same way
seismic waves travel through the earth after an earthquake.
7. The displaced bar represents a fault that has suddenly moved.
4. How is the energy transmitted? As seismic waves. Two important types of seismic waves are the P
and S waves.
P wave: Also called primary or compressional waves, P waves carry energy through the Earth
as longitudinal waves, moving particles in the same line as the direction of the wave.
These waves are the fastest body waves and arrive at seismic recording stations before
the S waves, or secondary waves. P waves may be felt by humans as a bang or thump.
S wave: Also called secondary or shear waves, S waves carry energy through the Earth in very
complex patterns of transverse (crosswise) waves. These waves move more slowly than
P waves, but in an earthquake they are usually bigger.
A very good animation of earthquake waves can be viewed at
http://web.ics.purdue.edu/~braile/edumod/waves/WaveDemo.htm
To illustrate seismic waves use the following wave demonstration :
Demonstration 2: Seismic Waves
Purpose: to demonstrate the passage of P and S waves through a solid and a liquid.
Procedure:
1. Have about 10 students stand in a line, shoulder to shoulder, with linked elbows. The linked
elbows represent the solidity of rock.
2. The first person in line leans into the person next to them, pushing against their shoulder, and
then straightens back up. Again, the movement or wave is transferred to each person in the
line. This is the compressional or P wave.
3. The first person at one end of the line leans forward by bending at the waist, and then
straightens up again. Because their arms are linked, each person in the line does the same
movement, and the wave passes along the line of people. This is the shear or S wave.
4. Have the students remain shoulder to shoulder, but do not link elbows. (This represents liquid
conditions.) Repeat the two movements. Result: P waves can transmit through water : S
waves can not.
2
5. How are Earthquakes measured?
During an earthquake, vibrations initiated by fracturing of the Earth's
crust radiate outward from the point of fracture. Direct compressional
waves (P-waves) are faster moving and shear waves (S-waves) are
slower. Each type appears as a unique signature on a seismograph, a
very sensitive instrument used to record and measure earthquakes. The
visual record produced is called a "seismogram". (Show overhead 3, the
Seismogram)
Earthquakes can be measured two ways: Magnitude and Intensity. Magnitude of an earthquake is
determined based on measuring the ground motion with instruments (seismographs), whereas the
intensity of an earthquake is determined based on observations of earthquake effects on building
structures and human perceptions. (Show overheads 4 and 5 - Magnitude Scale and Modified
Mercalli Scale)
• Magnitude is a unique number representing the size of an earthquake and measures the
amount of fault movement at the source of the earthquake. Magnitude is measured from
<1 (recorded but not felt) to 9 or even greater (seriously damaging). This is a logarithmic
scale and each value is 10 times greater than the preceding number on the scale.
Magnitude is calculated based on arrival times and amplitude of earthquake waves
recorded by a seismograph. The largest earthquake ever recorded was a magnitude 9.5 in
Chile in 1960. Canada’s largest recorded earthquake (magnitude 8.1) occurred along the
Queen Charlotte Fault in BC in 1949.
• Intensity is a measure of local shaking and therefore differs from place to place. The
strength of shaking generally decreases with distance from the source, but also is
influenced by local geologic conditions. For example, thick deposits of soft soils will
experience much greater shaking than will hard bedrock. Intensity is measured on the
Modified Mercalli Scale – a numeric scale from I to XII, which is based on people’s
descriptions of what was felt and the amount of damage incurred in their location during the
earthquake. For any earthquake, there is only one magnitude but as many intensities as
there are communities reporting effects.
6. Where do earthquakes occur? Show overhead 2, the Tectonic Plates map.
Earthquakes occur all over the world; however, most occur on active faults that define the major
tectonic plates of the earth. Ninety percent of the world's earthquakes occur along these plate
boundaries. The "Ring of Fire" circling the Pacific Ocean, and including Canada's west coast, is one
of the most active earthquake and volcanic areas in the world.
7. Where do most of the earthquakes happen in Canada?
Using the Earthquakes in Canada map, have students identify hazard regions where earthquakes
are common.
• Earthquakes along Canada’s west coast occur at or near the margins of slowly moving tectonic
plates.
• In Eastern earthquakes are not at the edge of a tectonic plate. They are in regions of crustal
weakness. The slow movement of the North American Plate away from the Mid-Atlantic Ridge
may activate old zones of weakness and faults such as the St. Lawrence Valley.
• In the Arctic, earthquakes also seem to be associated with older geological features, but may
also be related to stresses produced as the land continues to rise following melting of the heavy
ice sheets from the last continental glaciation.
Although some regions may have earthquakes,
uakes, human risk is slight if few people live there. Ask the
students which regions of Canada have significant risk associated with this hazard. (southern
Cordillera and St. Lawrence Lowlands)
3
Natural Resources Canada 2011: Lesson Plan - Grades 7 to 9
Overhead 1
Earthquakes in Canada
Population Density
by Census Division (persons /
km2 )
< 0.1
0.1 - 0.9
1 - 4.9
5 - 19.9
20 - 49.9
50 - 150
> 150
J.M. Aylsworth, Geological Survey of Canada, Natural Resources Canada.
Tectonic Plates
Courtesy of the USGS
Overhead 2
Overhead 3
Seismogram
Diagram showing arrival of the P waves and S waves
Actual seismogram of the arrival of seismic waves
at station KILO on Dec. 7, 2006. Magnitude 4.2 earthquake.
Overhead 4
Magnitude Scale
•
A unique number representing the size of an earthquake.
•
Magnitude is the measure of the amount of energy released by the
earthquake.
Magnitude
Under 3
Earthquake Effects
Generally not felt, but recorded.
3-5
Often felt, but rarely causes damage.
5-6
At most slight damage to well-designed buildings. Can
cause significant damage to poorly constructed
buildings over small regions.
6-7
Can be destructive in areas up to about 100 kilometres
across where people live.
7-8
Major earthquake. Can cause serious damage over
larger areas.
8 or greater
Great earthquake. Can cause serious damage in areas
several hundred kilometres across.
Overhead 5
Intensity is a measure of local shaking based on ‘felt’ and damage reports
Intensity: Modified Mercalli Scale
Scale
Earthquake Effects
I
People do not feel any Earth movement.
II
A few people might notice movement if they are at rest and/or on the upper floors of tall
buildings.
III
Many people indoors feel movement. Hanging objects swing back and forth. People outdoors
might not realize that an earthquake is occurring.
IV
Most people indoors feel movement. Hanging objects swing. Dishes, windows, and doors
rattle. The earthquake feels like a heavy truck hitting the walls. A few people outdoors may feel
movement. Parked cars rock.
V
Almost everyone feels movement. Sleeping people are awakened. Doors swing open or close.
Dishes are broken. Pictures on the wall move. Small objects move or are turned over. Trees
might shake. Liquids might spill out of open containers.
VI
Everyone feels movement. People have trouble walking. Objects fall from shelves. Pictures fall
off walls. Furniture moves. Plaster in walls might crack. Trees and bushes shake. Damage is
slight in poorly built buildings. No structural damage.
VII
People have difficulty standing. Drivers feel their cars shaking. Some furniture breaks. Loose
bricks fall from buildings. Damage is slight to moderate in well-built buildings; considerable in
poorly built buildings.
VIII
Drivers have trouble steering. Houses that are not bolted down might shift on their foundations.
Tall structures such as towers and chimneys might twist and fall. Well-built buildings suffer
slight damage. Poorly built structures suffer severe damage. Tree branches break. Hillsides
might crack if the ground is wet. Water levels in wells might change.
IX
Well-built buildings suffer considerable damage. Houses that are not bolted down move off
their foundations. Some underground pipes are broken. The ground cracks. Reservoirs suffer
serious damage.
X
Most buildings and their foundations are destroyed. Some bridges are destroyed. Dams are
seriously damaged. Large landslides occur. Water is thrown on the banks of canals, rivers,
lakes. The ground cracks in large areas. Railroad tracks are bent slightly.
XI
Most buildings collapse. Some bridges are destroyed. Large cracks appear in the ground.
Underground pipelines are destroyed. Railroad tracks are badly bent.
XII
Almost everything is destroyed. Objects are thrown into the air. The ground moves in waves or
ripples. Large amounts of rock may move.
Natural Resources Canada 2011: Lesson Plan - Grades 3 to 5
Earthquake activity 2:
Creative Essay
Description: Students write a ‘newspaper article’ describing an earthquake, written as if they
were there at the time of the event.
Materials:
Overheads: 1. Modified Mercalli intensity scale
2. Saguenay earthquake modified Mercalli intensity map
3. Vancouver Island earthquake modified Mercalli intensity map
Student worksheet
Teacher instructions:
Before assigning the ‘newspaper’ essay, briefly explain the terminology and read a description of an
actual earthquake so the class can understand the possible effects associated with each intensity.
1. Explain epicentre, magnitude and intensity to the class. Write the term and its definition on the
blackboard. Project Overhead 1 or distribute the Modified Mercalli Intensity Scale chart to the class to
explain how intensity is measured.
Epicentre is the position on the surface of the Earth directly
above the location of the earthquake. Note: The amount of
ground shaking decreases as you move away from epicentre.
Magnitude is a unique number representing the size of an
earthquake and measures the amount of fault movement at the source of the earthquake.
An earthquake has only one magnitude, however it has many values for intensity.
Intensity is a measure of local shaking and therefore differs from place to place.
• Intensity describes how the shaking was felt by people and how much damage was
done to buildings.
• Scientists have created the Modified Mercalli Scale (MM) as a way of measuring the
intensity of an earthquake. For example, at MM I, although instruments have recorded
an earthquake, shaking was so slight that no one felt it. At MM III, many people who
are indoors felt it. At MM V1, everyone felt it. At MM X, most buildings are destroyed.
• Intensity varies from place to place. It is greatest at locations close to the epicentre and
less at locations further away from the epicentre.
2. As an example of varying intensity values, read one or both of the accompanying descriptions of an
earthquake to the class (p.2). Use Overheads 2 and 3 intensity maps. At each Modified Mercalli
(MM) intensity mentioned, have a student read out loud to the class the appropriate description from
the accompanying chart.
3. Ask the students to imagine that an earthquake has just occurred and that they are a newspaper
reporter who lives in a city that was impacted by the earthquake. Have the students create a
newspaper article, reporting on the earthquake. The students should describe what they felt, heard
and saw during the earthquake and also describe how people reacted to the event. This is intended
to be a creative impression of what people would experience during the event rather than a geological
analysis of the event. Students should use some of the vocabulary that they have learned. Students
should chose a particular intensity for their city and then their descriptions should reflect the impacts
of that intensity.
4. Distribute the worksheet of instructions.
J.M. Aylsworth, Geological Survey of Canada, Natural Resources Canada
1
Descriptions of an earthquake to read aloud:
The 1988 Saguenay earthquake
On Friday November 25, 1988, at 6:46 in the evening, eastern Canada and the northeastern United
States were shaken by the largest earthquake that has occurred in the last 75 years. It had a magnitude
of 5.9, which is very large for eastern North America (maximum magnitude 7 to 8). The epicentre was
located in the Saguenay valley near the cities of Chicoutimi and Jonquière, which are northeast of
Quebec City. Fortunately, nobody was killed during the Saguenay earthquake, however shaking was felt
up to 1000 km away.
Near the epicentre (Chicoutimi-Jonquière-La Baie area) of the earthquake it was felt with an average
intensity of MM VII. In a few places it was even felt with an intensity of MM VIII. For the most part, near
the sparsely-populated epicentre, damages were limited to fallen chimneys and cracked plaster walls,
and there were a few small landslides.
Within a range of 500 km it was felt by most people with an average intensity of MM IV-V.
Within a range of 1000 km, it was felt by many with an average intensity of MM III.
The M7.3 Vancouver Island Earthquake of 1946
On Sunday June 23, 1946, at 6: 10:15 in the morning, British Columbia and part of northwestern United
States were shaken by the largest earthquake that has occurred onshore in Canada in historic times. It
had a magnitude of 7.3. The epicentre was located in the Forbidden Plateau area of central Vancouver
Island, just to the west of the communities of Courtenay and Campbell River. This earthquake caused
considerable damage on Vancouver Island, and was felt as far away as Portland, Oregon, and Prince
Rupert, B.C. Two deaths resulted from this earthquake, one due to drowning when a small boat capsized
in an earthquake-generated wave, and the other from a heart attack in Seattle.
Near the epicentre (Cumberland, Union Bay, and Courtenay), the earthquake knocked down 75% of the
chimneys. It also did considerable damage in Comox, Port Alberni, and Powell River (on the eastern side
of Georgia Strait). Within a radius of about 100 km of the epicentre the earthquake was felt with an
intensity of MM VII or VIII.
Within a range of 250 km from the epicentre it was felt by most people with an average intensity of
MM VI. A number of chimneys were shaken down in Victoria and people in Victoria and Vancouver were
frightened – many running into the streets.
Within a range of 350 or 400 km from the epicentre it was felt by most people with an average intensity
of MM V.
Within a range of about 600 km from the epicentre it was felt by people with an intensity of MM IV or
less.
2
Overhead 1: Modified Mercalli Scale chart
Intensity: Modified Mercalli Scale
Scale
Earthquake Effects
I
People do not feel any Earth movement.
II
A few people might notice movement if they are at rest and/or on the upper floors of tall
buildings.
III
Many people indoors feel movement. Hanging objects swing back and forth. People outdoors
might not realize that an earthquake is occurring.
IV
Most people indoors feel movement. Hanging objects swing. Dishes, windows, and doors
rattle. The earthquake feels like a heavy truck hitting the walls. A few people outdoors may feel
movement. Parked cars rock.
V
Almost everyone feels movement. Sleeping people are awakened. Doors swing open or close.
Dishes are broken. Pictures on the wall move. Small objects move or are turned over. Trees
might shake. Liquids might spill out of open containers.
VI
Everyone feels movement. People have trouble walking. Objects fall from shelves. Pictures fall
off walls. Furniture moves. Plaster in walls might crack. Trees and bushes shake. Damage is
slight in poorly built buildings. No structural damage.
VII
People have difficulty standing. Drivers feel their cars shaking. Some furniture breaks. Loose
bricks fall from buildings. Damage is slight to moderate in well-built buildings; considerable in
poorly built buildings.
VIII
Drivers have trouble steering. Houses that are not bolted down might shift on their foundations.
Tall structures such as towers and chimneys might twist and fall. Well-built buildings suffer
slight damage. Poorly built structures suffer severe damage. Tree branches break. Hillsides
might crack if the ground is wet. Water levels in wells might change.
IX
Well-built buildings suffer considerable damage. Houses that are not bolted down move off
their foundations. Some underground pipes are broken. The ground cracks. Reservoirs suffer
serious damage.
X
Most buildings and their foundations are destroyed. Some bridges are destroyed. Dams are
seriously damaged. Large landslides occur. Water is thrown on the banks of canals, rivers,
lakes. The ground cracks in large areas. Railroad tracks are bent slightly.
XI
Most buildings collapse. Some bridges are destroyed. Large cracks appear in the ground.
Underground pipelines are destroyed. Railroad tracks are badly bent.
XII
Almost everything is destroyed. Objects are thrown into the air. The ground moves in waves or
ripples. Large amounts of rock may move.
Overhead 2: Saguenay earthquake modified Mercalli intensity map
Overhead 3: Vancouver Island earthquake modified Mercalli intensity map
Student worksheet 1
Earthquake Article
Name:
1. Choose any Canadian city. Your city is
.
2. Imagine that it has just been shaken by a large earthquake. Imagine what it felt like.
Imagine what would have happened.
3. Choose an earthquake intensity from V to IX on the Modified Mercalli scale. This will be the intensity
felt in your chosen city. Your intensity is
.
Intensity: Modified Mercalli Scale
Scale
Earthquake Effects
V
Almost everyone feels movement. Sleeping people are awakened. Doors swing open
or close. Dishes are broken. Pictures on the wall move. Small objects move or are
turned over. Trees might shake. Liquids might spill out of open containers.
VI
Everyone feels movement. People have trouble walking. Objects fall from shelves.
Pictures fall off walls. Furniture moves. Plaster in walls might crack. Trees and bushes
shake. Damage is slight in poorly built buildings. No structural damage.
VII
People have difficulty standing. Drivers feel their cars shaking. Some furniture breaks.
Loose bricks fall from buildings. Damage is slight to moderate in well-built buildings;
considerable in poorly built buildings.
VIII
Drivers have trouble steering. Houses that are not bolted down might shift on their
foundations. Tall structures such as towers and chimneys might twist and fall.
Well-built buildings suffer slight damage. Poorly built structures suffer severe damage.
Tree branches break. Hillsides might crack if the ground is wet. Water levels in wells
might change.
IX
Well-built buildings suffer considerable damage. Houses that are not bolted down
move off their foundations. Some underground pipes are broken. The ground cracks.
Reservoirs suffer serious damage.
4. Pretend that you are a local newspaper reporter and write a short newspaper article (approx. 300
words) about this event for your newspaper. Your job is to tell your readers all about the damage,
what happened, what you felt, heard and saw during the event and how local people reacted to the
damage.
• You can use ‘pretend’ quotes from eyewitnesses.
• Include a dramatic newspaper headline (title).
• You can illustrate your article with a drawing or map.
When writing your article be sure that your description fits your chosen Modified Mercalli Intensity scale.
Please print your chosen scale in the upper right corner of your paper.
1
Natural Resources Canada 2011: Lesson Plan - Grades 7 to 9
Earthquake activity 4:
Earthquake Vocabulary Game
Description: Crossword puzzle, using earthquake terminology.
Materials:
crossword puzzle worksheet
Teacher instructions:
This activity uses the vocabulary introduced in activity 3.
1. Distribute the puzzles.
Answers to puzzle:
Across
3 Seismograph
6 Epicentre
9 Magnitude
10 Shear
13 Seismicwaves
18 Pacific
20 Landslide
Down
1 Seismogram
2 Zone
4 Tectonic
5 Stress
7 Compressional
8 Mercalli
11 Focus
12 Earthquake
14 Intensity
15 Fault
16 Tsunami
17 Arrival
18 Plate
19 Felt
21 Energy
J. M. Aylsworth, Geological Survey of Canada, Natural Resources Canada.
1
Student worksheet 1
Earthquakes
Name:
1
2
3
4
5
6
7
8
9
10
11
12
13
15
16
14
17
18
20
Across
3 Sensitive instrument used to record and
measure earthquakes
6 The point on the earth's surface directly
above the subsurface location of
the earthquake
9 The unique measure of the amount of
energy released during an
earthquake
10 The S wave is also called the
wave
13 How earthquake energy is transmitted
(2 words, ignore the space)
18 The ‘Ring of Fire’ encircles this ocean
20 An abrupt downhill movement of rock
and soil, possibly triggered by an
earthquake
19
21
Down
1 Recording of ground motions
2 A region in which earthquakes are common is a seismic
4 Large segments of the earth’s crust and upper mantle are known as
plates
5 Force which can lead to sudden movement along a fault
7 The P wave is also called the
wave
8 A numeric scale from I to XII that describes earthquake effects
11 The subsurface location at which the energy of an earthquake is
released
12 Sudden shaking of the ground
14 How the earthquake was felt locally
15 Zone of fractures or breaks in rocks where movements occur
16 A series of huge ocean waves that might be caused by an earthquake
17 The time at which a particular wave phase arrives at a seismograph
time
station is known as the
18 Many earthquakes in western North America are associated with the
Juan de Fuca
.
19 The Mercalli Scale is based on people’s reports of what was
locally
21 An earthquake is the result of a sudden release of
Natural Resources Canada 2011: Lesson Plans - Grades 6 to 8
Earthquake activity 5:
Design an Informative Brochure on
Earthquakes and Safety
Description: Students create a brochure about earthquakes, focusing on advice on how to increase
personal safety.
Materials:
student worksheet
Teacher instructions:
Have the class research earthquake preparedness and then to create an informative brochure advising
people about how we can prepare for earthquakes to increase our safety.
Information can be found on these websites:
o
Public Safety Canada http://getprepared.ca/knw/ris/eq-eng.aspx
o
Geological Survey of Canada: http://earthquakescanada.nrcan.gc.ca/index_e.php
J. M. Aylsworth, Geological Survey of Canada, Natural Resources Canada
1
Student worksheet 1
Name:
Earthquake Brochure
Design and create a brochure to teach people how to stay safe in an earthquake. Fold a piece of paper in
three sections. You can work on both sides of the paper.
Your goal is to tell people about earthquakes and let them know how to stay safe in an earthquake.
The information should cover what to do in advance to reduce risk, what to do during an earthquake, and
what to do after an earthquake happens.
Information can be found on these websites:
o
Public Safety Canada http://getprepared.ca/knw/ris/eq-eng.aspx
o
Geological Survey of Canada: http://earthquakescanada.nrcan.gc.ca/index_e.php
Include pictures or drawings to make your brochure more interesting.
Natural Resources Canada 2001: Lesson Plan - Grades 7 to 12
Earthquake activity 6:
Earthquakes in Canada
Description: A student research activity that explores the Earthquakes Canada website to answer
questions about Canadian and local earthquakes. For senior elementary and secondary
school students, the sophistication of the students’ answers should reflect their grade in
school.
Materials:
access to internet
student worksheet (2 pages)
Teacher instructions:
This is an on-line research activity for senior elementary and secondary school students, using the
information provided by Natural Resources Canada’s Earthquakes Canada website,
http://earthquakescanada.nrcan.gc.ca. Students will answer the questions on the accompanying student
worksheet. The sophistication of their answers should reflect their grade in school.
Answers:
This website is continually updated. Answers to most questions will vary depending on the date and your
local community.
1. a. An earthquake signal will have a sudden increased in amplitude and the left, or "leading" edge of
each "burst" is very square. On the right, the amplitude of the signal level begins to fall off as the
earthquake energy dissipates gradually over time.
b. Other vibrations, in addition to earthquakes, recorded by seismographs include the passage of
trains and ships, as well as explosions and even strong winds. Network system noise is also
recorded.
2. Answer will vary, but since this is a Canada wide list, not all of the selected stations will have
vibrations and the vibrations may not have been caused by an earthquake.
3. a. Most earthquakes are distributed around the outer part of the continent – the west coast and
mountains, the Arctic Islands, and southeastern Canada (Maritimes, southern Quebec).
b. Most common: off the coast of British Columbia
c. Least common: Central Canada – the Canadian Shield and the Prairies.
4. a. The most recent earthquake reported in Canada is indicated by the yellow dot on the map and is at
the top of the list.
b. Although the epicentre is outside of Canada, ground vibrations were recorded in Canada.
5. Answers will vary: some students will choose the most recent (yellow dot) in their seismic zone, while
others may pick the closest to their community. Student living in seismic zones should zoom into the
map as much as possible. Students in locations far from major seismic zones wil have to use
earthquakes at greater distances.
6. Answers will vary depending on the location of your community. A “significant” earthquake may be
considered to refer to a high magnitude earthquake, an earthquake associated with significant
damages, or an earthquake of considerable scientific interest. These are indicated or inferred in the
web text for each seismic zone
J. M. Aylsworth, Geological Survey of Canada, Natural Resources Canada.
1
Student Worksheet 1
Earthquakes in Canada
Name:
Earthquakes occur in most parts of Canada, although they are most common in certain specific regions.
Explore the many features of the Earthquakes Canada website http://earthquakescanada.nrcan.gc.ca to
learn about earthquakes in Canada, and, more specifically, earthquakes near your community.
Answer the following questions.
1. In the index in the left margin, select < Seismogram viewer > and then click on < Interpreting
Seismograms > in the text. Read it.
a. Describe an earthquake signal .
b. What other vibrations, in addition to earthquakes, can be recorded by seismographs?
2. Return to < Seismogram viewer > in left margin. (This page allows you to view ground vibrations on
seismograms recorded at selected stations of the Canadian National Seismograph Network. Scroll to
the bottom of the page to see them. Some stations may have recorded shaking within the last hour)
a. What percentage of these stations have recorded ground vibrations in the last hour?
b. Do some of the signals look like earthquake vibrations?
3. In the index in the left margin, select < Historic Events > and choose “Map of earthquakes in
Canada”. Observe the distribution of seismic events.
a. Describe the distribution of events.
b. Where are earthquakes most common?
c. Where are earthquakes least common?
4. In the index in the left margin, select < EqCan home > to view a map and a list of earthquakes that
have happened during the last 30 days in Canada. Scroll down to “In Canada” and click on < The
map and list of recent earthquakes >. The earthquakes shown on the map are also listed below the
map at the bottom of the page.
a. Where, when, and what magnitude was the most recent earthquake recorded in Canada?
1
Student Worksheet 2
b. Where, when, and what magnitude was the largest magnitude earthquake recorded in
Canada in the last 30 days?
c. Why are some earthquakes with epicentres outside of Canada shown on the Canadian
map?
5. By clicking within the blue rectangular outlines on the earthquake map, you can zoom into a specific
region. Zoom as far as possible into your region. (Note: Not all parts of Canada are in major seismic
zones. If your community does not lie within a specific seismic zone, it may be difficult to find a
nearby earthquake and you will have to consider ones further afield.)
a. Where, when, and what magnitude was the most recent earthquake recorded close to your
community in the last 30 days?
Immediately above the map, you have the option to change the time period of the map from the last
30 days to1 or 5 years duration.
b. Where, when, and what magnitude was the largest earthquake recorded close to your
community in the last 5 years? (in the last 1 year for students in southwest B.C.)
6. In the index in the left margin, select < General Information > and then click on < Earthquake Zones in
Canada > in the text.
a. In which, if any, seismic zone does your community lie?
b. Describe your local seismic zone.
c. Have ‘significant’ earthquakes occurred in your zone?
Give an example.
d. What is the likely cause of earthquakes in your seismic zone?
2
Natural Resources Canada 2011: Lesson Plan - Grades 7 to 12
Earthquake activity 7:
Locate the Earthquake Exercise
Description: Students will learn to read a seismogram and calculate the epicentre of a Canadian
earthquake.
Materials:
Overhead 1: Summary of method
Seismograms and maps (Select one of the two-page groups.) for each student
Student worksheets
Teacher instructions:
1. Review seismic waves with the students.
When an earthquake occurs, vibrations initiated by fracturing of the earth's crust radiate outward
from the point of fracture.
P wave: Also called primary or compressional waves, P waves carry energy through the Earth
as longitudinal waves, moving particles in the same line as the direction of the wave.
These waves are the fastest body waves. P waves are generally felt by humans as a
bang or thump.
S wave: Also called secondary or shear waves, S waves carry energy through the Earth in very
complex patterns of transverse (crosswise) waves. These waves move more slowly than
P waves, but in an earthquake they are usually bigger.
2. Using the overhead provided, show the students how to calculate distance and find the epicentre.
Direct compressional waves (P waves) are faster moving and shear waves (S waves) are
slower. Each type appears as a unique signature on a seismogram, the visual record produced
by a seismograph.
At the recording station, the difference in arrival time of the P waves and S waves is used to
calculate the distance to the epicentre of the earthquake.
Using triangulation, the calculated distances from several different seismic recording stations can
be plotted to locate the epicentre. Three stations are a minimum. Accuracy increases with more
stations.
3. Chose the seismogram package nearest to your community from the accompanying pages. Each
package contains four seismograms on one page and a regional map on a second page. Distribute
the worksheets and your chosen 2 page seismogram and map package to the students.
Group A: Eastern Canada
Answer : 10 km SE of Val-des-Bois, Quebec. (65 km northeast of Ottawa.) June 23, 2010.
Magnitude 5. Strongly felt in Ottawa. Widely felt in a 700-km radius from the epicentre in
western Quebec. Felt as far away as Kentucky and Chicago. Triggered 2 landslides.
Some minor structural damage.
Group B: Western Canada
Answer : 19 km ENE of Duncan, BC. (Vancouver Island) Februrary 15, 2011. Magnitude 2.9. Felt
in Duncan, Salt Spring Island, Ladysmith, Cowichan Bay, Chemainus and Richmond, BC.
There are no reports of damage, and none would be expected.
J. M. Aylsworth, Geological Survey of Canada, Natural Resources Canada.
1
Overhead 1: Summary of method
1. Identification of P wave and S wave
arrival times at a seismograph
station as recorded on the
seismogram:
Distance to the epicentre is calculated based on the
difference in the arrival times of P and S waves
2. Calculation of distance from the epicentre:
P-wave velocity = Vp = 6.2 km/sec
S-wave velocity = Vs = 3.65 km/sec
Difference in velocity = 2.55 km/sec
Time taken by P waves to travel a distance (D) from
the epicentre to a seismic station (km/sec)
TP = D / Vp = D / 6.2
Time taken by S waves to travel same distance from
the epicentre to a seismic station (km/sec)
TS = D / Vs = D / 3.65
Difference in arrival time (lag time) between P waves
and S waves (sec)
ΔT = TS - TP
= D / Vs - D / Vp
= D/3.65 - D/6.2
ΔT = 2.55 D / 22.63
Distance from the epicentre to the seismic station
3. Triangulate from the
seismograph stations
to find the epicentre
on a map.
D = 22.63 ΔT / 2.55
Student Worksheet 1
Name:
Find the Epicentre of an Earthquake
Background:
When an earthquake occurs, vibrations initiated by fracturing of the
earth's crust radiate outward from the point of fracture. Direct
compressional waves (P waves) are faster moving and shear waves (S
waves) are slower. Each type appears as a unique signature on a
seismogram, the visual record produced by a seismograph. At the
recording station, the difference in arrival time of the P and S waves is
used to calculate the distance to the epicentre of the earthquake.
P-wave velocity is 6.2 km/s and S-wave velocity is 3.65 km/s. The difference is 2.55 km/s.
Time taken by P-waves to travel a distance (D) from the epicentre to a seismic station : TP = D / 6.2
Time taken by S-waves to travel same distance from the epicentre to a seismic station : TS = D / 3.65
Difference in arrival time (lag time) between P- waves and S-waves is : ΔT = TS - TP
= D/3.65 - D/6.2
= 2.55 D / 22.63
∴ Distance from the epicentre to the seismic station is:
D = 22.63 ΔT / 2.55
1. Answer the following questions to demonstrate your understanding of this process.
a. How long would it take P waves to travel 100 km?
b. How long would it take S waves to travel 100 km?
c. What is the lag time between the arrival of P waves and S waves over a distance of 100 km?
d. If the difference in arrival time of P and S waves was 20 seconds, what is the distance between the
epicentre and the seismograph location?
2. Examine the seismograms provided by your teacher. Seismographs measured the time between the
arrival of P-waves and S-waves.
a. Identify and label the arrival of the P and S waves on the seismograms.
b. Calculate the distance to the epicentre from each station.
#
Recording station
Difference in arrival time
Distance from epicentre
1
2
3
4
c.
Triangulate the epicentre on the map. Inscribe a circle with a compass, such that the point of the
compass is on the location of the recording station and the radius of the circle is equal to the
calculated distance to the epicentre. Repeat for the other stations. The epicentre of the
earthquake is located near the point at which the circles approximately intersect. Mark and label
the epicentre on the map.
Compare the location on your map with an Atlas or Google Map.
Where is the epicentre of this earthquake? Near the town of
What is the minimum number of stations that are necessary to find an epicentre?
Group A. Eastern Canada: Magnitude 5 earthquake,
1
Group A. Eastern Canada
Name:
2
Group B. Western Canada: Magnitude 2.9 earthquake
1
Group B. Western Canada
Name:
2
Natural Resources Canada 2011: Lesson Plan - Grades 9 to 12
Earthquake activity 8:
Earthquake Quiz
Description: This is an independent study activity for senior secondary school students. Students will
read about earthquakes in Canada and then complete a quiz of true or false, or multiple
choice questions.
Teacher instructions and notes:
1. Refer your students to the information on earthquakes in Canada on the following websites:
Atlas of Canada http://atlas.nrcan.gc.ca/site/english/maps/environment/naturalhazards/earthquakes
Geological Survey of Canada http://earthquakescanada.nrcan.gc.ca/info-gen/faq-eng.php
2. Have students read the information on earthquakes and then complete the quiz on the following
pages. If a student chooses ‘false” on a true/false question, they must add a brief statement
explaining why the statement is false.
3. The correct answers are given below. Some talking points have been added for the teachers’ use.
Quiz answers and talking points for the teacher:
1. a) 3500 (8 to 10 every day) The number of earthquakes located in Canada has increased over the
years. This is due to more sensitive recording instruments and increased numbers of instruments
installed across the country. The actual number of earthquakes is not increasing.
2. b) 50 to 55 (1 every week) The majority of these felt earthquakes are too small to cause any damage.
In the entire twentieth century, about 20 earthquakes have caused significant damage in Canada.
3. a) True. Some of the world's largest earthquakes have occurred in Canadian territory, including the
magnitude 9 Cascadia earthquake of 1700 and the magnitude 8.1 Queen Charlotte Island
earthquake of 1949.
4. a) British Columbia. More than half (around 1800 per year) of Canada’s earthquakes occur in this
province and the neighbouring Pacific Ocean. Quebec comes in second with roughly 500 per year,
while the Yukon is third with 150. In contrast, Manitoba, Saskatchewan and Prince Edward Island
are Canada’s quietest provinces, seismically speaking. On average, only 1 or 2 earthquakes are
recorded each year in these three provinces.
5. a) True, but the exact number of people is unknown and depends on how one determines if the
fatalities are directly or indirectly related to the earthquake.
6. e) All of the above. These varied lines of evidence helped to show that a giant (estimated magnitude
9) earthquake occurred along the Cascadia Subduction Zone at about 9 p.m. Pacific Standard Time
on January 26, 1700.
7. c) 1150 kilometres. The earthquake occurred along the Cascadia Subduction Zone, which extends
from offshore of central Vancouver Island to northern California.
8. e) 2600 MT, the equivalent of 2.6 billion tonnes of TNT explosive.
9. d) 10 to 12. Of these, five earthquakes have been assigned a magnitude 6 or greater: 1663, 1791,
1860, 1870 and 1925 (most magnitudes are based on historical intensity and damage reports). The
1988 earthquake did not have its epicentre in Charlevoix but in the Saguenay region. Every year,
more than 200 (mostly small) earthquakes are recorded in this region. Of these, only 4 or 5 are felt.
J. M. Aylsworth, Geological Survey of Canada, Natural Resources Canada.
1
10. d) 2 000 000 km2. Although the damage from this earthquake was limited to the immediate vicinity of
the epicentre and scattered pockets in the cities of Québec and Trois-Rivières, it was widely felt in
eastern Canada and the United States, from Nova Scotia to western Ontario and from James Bay
to Kentucky.
11. f) None of the above. Most earthquakes in Canada occur at some depth (between 5 to 50 kilometres)
on faults that never reach the surface and are unaffected by surface temperature, time of day or the
tides. Large, damaging earthquakes release millions of times the energy of small earthquakes and
their strength is unaffected by these relatively tiny events. Faults do not separate to create chasms
and, in Canada, the vast majority of faults visible on the surface were formed thousands or even
millions of years ago and have not been proven to be seismically active.
12. True. Intensity values are based on how the earthquake was felt in each location and will vary from
city to city depending on distance from the epicentre and local geological conditions,
13. a) It has no limits. Magnitude scales are not physical measuring instruments. They are numbers
determined from a mathematical formula based on the amplitude of seismic waves recorded at
different distances. Each unit on the Richter scale represents a 10-fold increase in the amplitude of
the measured seismic waves. Seismographs can record very small ‘microseisms’ (magnitude –1 to
–2). Generally, earthquakes must have a magnitude of 2 or 3 before they are widely felt. The
largest instrumentally measured earthquake in the world had a magnitude of 9.5 and occurred off
the coast of Chile in 1960.
14. d) between 1 and 12.
15. d) 5 to 7 kilometres per second. A large earthquake occurring on Canada’s west coast will be
recorded across the country, the fastest seismic waves arriving on Canada’s east coast, 5000
kilometres away, in a matter of minutes. The magnitude 8.1 earthquake off British Columbia’s
Queen Charlotte Islands on August 22, 1949 (the largest earthquake in Canada in the twentieth
century) was recorded by instruments across the country and around the world.
16. a) Pressure wave.
17. e) $15 billion. The $15 billion does not include loss of revenue due to the shut down of businesses in
order to recover from the earthquake.
18. d) All of the above. Consult Public Safety Canada or your provincial emergency preparedness
organization for information on how to prepare for natural disasters in Canada.
19. c) Head for high ground immediately! Never go to the coast to watch a tsunami. A tsunami moves
faster than a person can run. Residents of coastal areas should be prepared to evacuate to high
ground immediately. Depending on an earthquakes origin, a tsunami could reach the coast in as
little as 15 minutes or more than 15 hours later. Only after you have reached high ground (a
minimum of 10 to 15 metres above sea level) should you listen to local media for further
instructions. A tsunami is composed of several waves, and often the first wave is not the largest. Do
not return to the coast until you have been told it is safe to do so.
20. False. Vibrations from explosions, rock blasts and even landslides are strong enough to register on
local seismographs.
2
Student worksheet 1
Quiz : EARTHQUAKES
Name:_________________________
Select the correct answer. If you answer false on a true or false question, you must explain why the
statement is false.
1. On average, how many earthquakes are recorded and located in or near Canada each year?
a) 3500 (8 to 10 every day)
d) 100 (2 every week)
b) 1000 (2 to 3 every day)
e) 10 (1 every month)
c) 350 (1 every day)
2. The majority of earthquakes are either too small or too remote to be felt. How many earthquakes are
reportedly felt each year in Canada?
a) 350 to 400 (1 every day)
c) 10 to15 (1 every month)
b) 50 to 55 (1 every week)
d) 1 to 2 (1 every year)
3. There have been several very large earthquakes in Canada. True or False?
4. Which province or territory has the most earthquake activity?
a) British Columbia
d) Quebec
b) Manitoba
e) Yukon
c) Nunavut
5. Someone has been killed by an earthquake in Canada. True or False?
6. The Cascadia earthquake in 1700 occurred a century before the start of the written historical record of
the Pacific northwest. How did scientists determine the date, location and size of this event?
a) Carbon dating of drowned cedar trees preserved in tidal marshes.
b) Examination of deep sea cores of mud layers off the coast of Washington and Oregon.
c) Oral traditions of native tribes of the Pacific northwest.
d) Japanese written records of a tsunami that struck the coast of Honshu with no associated
earthquake noted.
e) All of the above.
7. The estimated length of the fault that ruptured during the Cascadia megaquake in 1700 was:
a) 100 kilometres (equivalent to the distance from Vancouver to Victoria)
b) 600 kilometres (equivalent to the distance from Vancouver to Banff)
c) 1150 kilometres (equivalent to the distance from Vancouver to Saskatoon)
d) 1850 kilometres (equivalent to the distance from Vancouver to Winnipeg)
e) 3200 kilometres (equivalent to the distance from Vancouver to Toronto)
1
Student worksheet 2
8. The energy released by the Cascadia earthquake in 1700 was equivalent, as measured in megatons
(MT) of TNT explosive, to:
a) 0.003 MT (the 1917 explosion of the Mont-Blanc in Halifax harbour)
b) 0.015 MT (the 1945 explosion of the Hiroshima atomic bomb)
c) 24 MT (the 1980 explosion of the Mount St. Helens volcano)
d) 50 MT (the 1961 Tsar Bomba Soviet nuclear test, the world’s largest)
e) 2600 MT (the total estimated annual energy consumption for all of Canada)
9. The Charlevoix-Kamouraska region, northeast of the city of Québec, is one of Canada’s most active
seismic zones. How many damaging earthquakes have been recorded there in the past 350 years?
a) 1 or 2
c) 7 or 8
b) 3 or 4
d) 10 to 12
10. The magnitude 6.2 earthquake of February 28, 1925 in the Charlevoix-Kamouraska region was felt
over an area of approximately:
a) 73 500 km2 (the size of New Brunswick)
b) 480 000 km2 (the size of the Yukon)
c) 650 000 km2 (the size of Manitoba)
d) 2 000 000 km2 (the size of British Columbia and Ontario combined)
e) 9 900 000 km2 (the size of Canada)
11. Which of the following statements are true?
a) There are more earthquakes in the winter than summer.
b) The earth opens up when there is a big earthquake.
c) Many small earthquakes ‘let off steam’ so there won’t be a big one.
d) The earth’s tides can trigger earthquakes.
e) There is a fault in my region, so there must be earthquakes.
f) None of the above.
12. An earthquake has only one magnitude but will have many intensity values.
True or False?
13. How large is the earthquake magnitude scale?
a) it has no limits
d) between 1 and 10
b) about 30 centimetres
e) between 1 and 100
c) between –5 and +5
14. How large is the Modified Mercalli Intensity scale?
a) it has no limits
c) between 0 and 21
b) between 1 and 9
d) between 1 and 12
15. How fast do seismic waves travel through the crust of the earth?
a) 0.012 km/sec. (top speed of an Olympic sprinter, 43 km/hr)
b) 0.1 km/sec. (top speed of a Formula One race car, 360 km/hr)
c) 0.34 km/sec. (speed of sound in air, 1225 km/hr)
d) 5 to 7 km/sec. (almost the speed of the space shuttle as it orbits the earth, 28000 km/hr)
2
Student worksheet 3
16. Which seismic wave travels fastest and appears first on a seismogram?
a) pressure wave
b) shear wave
c) Raleigh wave
17. According to a study by the insurance industry, a magnitude 6.5 earthquake occurring beneath the
Strait of Georgia would cause the following amount of damage to greater Vancouver’s buildings and
their contents:
a) $40 million (Celine Dion’s annual salary)
b) $350 million (construction cost of the CN Tower)
c) $1 billion (construction cost of the 13 kilometre Prince Edward Island–New Brunswick
Confederation Bridge)
d) $2 billion (value of annual diamond production in Canada)
e) $15 billion (total volume of sales processed through Canadian travel agencies)
18. During an earthquake:
a) If you are inside, take cover under a heavy table, desk or any solid furniture and hold on. If you
can't get under something strong, flatten yourself or crouch against an interior wall
b) If you are outside, stay outside, away from buildings, power lines, gas and water mains, and
telephone poles.
c) If you are in a car, try to pull over to a safe place where you are not blocking the road. Stop the car
and stay inside. Avoid bridges, overpasses, underpasses, buildings or anything that could
collapse on you and your car.
d) All of the above.
19. If you are on the coast and feel strong earthquake shaking, you should:
a) Go down to the shore to watch the unusual waves.
b) Tune in to your local media and await further instructions.
c) Head for high ground immediately.
20. Explosions are too weak to be recorded on a seismograph. True or False?
3
Natural Resources Canada 2011: Lesson Plan - Grades 9 to 12
Earthquake activity 9:
Earthquake Damage and Earthquake Preparedness
Description: A student research activity on earthquake hazards and ways to reduce risk, culminating in
group presentations to the class.
Teacher instructions:
This is an independent research activity for secondary school students, culminating in group
presentations to the class.
Divide the class into small groups and assign one research topic to each group.
Natural Resources Canada’s website Earthquakes Canada, http://earthquakescanada.nrcan.gc.ca,
is a good place to start their research. “Frequently Asked Questions” under <General Information>
includes information addressing the engineering topics.
In addition to the Earthquakes Canada website, Public Safety Canada’s website Get Prepared,
http://www.getprepared.gc.ca , is a good source of information on personal preparedness. Select
<Know the Risk>.
Depending on their topic, the group should consider what potential problems or damages may occur and
why, provide examples if possible, and explain how the proper design, early warning, local planning, or
personal preparedness, etc., can reduce risk and increase safety.
Each group should compile a poster or PowerPoint presentation on their topic and make a formal
presentation to the class.
Topics:
• Earthquake hazard and urban centres (Note: The emphasis should not be on large buildings,
which are covered by the next topic.)
• Earthquake hazard and large buildings and the National Building Code
• Earthquake hazard and electrical and communication lines and pipelines
• Earthquake hazard and roads and railways and bridges
• Earthquake hazard and dams and reservoirs
• Earthquake hazard and tsunamis
• Earthquake hazard and landslides
• Personal preparedness
J. M. Aylsworth, Geological Survey of Canada, Natural Resources Canada.
1