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Lecture 1
Introduction
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Photo: C. Samson
Crater of Poas volcano,
Costa Rica
INTRODUCTION
Professor: Jason Mah, Ph.D.
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Lecture objectives
• To distinguish between natural hazards and
natural disasters
• To know the 4 energy sources that fuel the
different natural disasters
• To describe several global and Canadian
trends related to natural disasters
• To know the 4 pillars of emergency
management (+adaptation) and to be able
to give examples of them
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Contents
• What is a natural disaster?
• Natural hazards
• Sources of energy fuelling natural
disasters
• Global trends
• Canadian trends
• Risk and mitigation
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Colour code
• Very important material
• Terms to remember in blue
• Hint: learn more than the definition.
Note the tables, graphs, figures, etc.
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What is a natural disaster?
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Etymology
Disaster
• dis- "away, without" +
astro "star, planet"
– Greek origin
– Astrological meaning
→ Litterally: "ill-starred"
– Event causing great & sudden damage.
Blamed on an unfavorable position of a
celestial body in the sky
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• Which disasters?
– Not covered:
• Human-made disasters
→ Deepwater Horizon oil spill,
Gulf of Mexico 2010
→ Savar building collapse, Dakha,
Bangladesh 2013 (1126 fatalities)
• Biological disasters
→ H1N1 epidemic 2010
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• Which disasters?
– Covered: Natural disasters
• Disasters linked to the place of
planet Earth in space (e.g. impacts
with space objects) and to active
terrestrial processes (e.g. plate
tectonics and weather)
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Definition
Natural disaster
• An extreme natural event in which a
large amount of energy is released
in a short time with catastrophic
consequences for life and
infrastructure in the vicinity
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Natural disaster - Attributes
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•
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•
•
•
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Significant casualties
Destructive impact on infrastructure
Disruption to society
Large economic losses
Call for exterior help
Media coverage
Government involvement
→ Key aspect is impact on society
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Natural disaster (?)
• A large earthquake occurs:
– In Vancouver: YES
– On an uninhabited Arctic island: NO
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Natural (?) disaster
HumanContinuum
made
• An overcrowded ferry capsizes
• An overcrowded ferry capsizes
during a hurricane
• A ferry capsizes
during a hurricane
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Natural
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Natural (?) disaster
• Misnomer
– Gives the impression that disasters
are only the fault of nature
– “Natural” disasters often triggered
when society ignores natural hazards
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Natural hazards
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Natural hazard
• Natural hazard: a source of danger
that exists in the environment and that
has the potential to cause harm
• Hazards are potentially damaging
• Examples of natural hazards:
– Unstable snow and rock on a
mountain slope
– High water levels
– Lightning bolt
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Natural hazard
• “Natural hazards are inevitable, but
natural disasters are not”
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Hazards and disasters
• "Disasters occur when hazards meet
vulnerability” (Blaikie, 1994)
Natural
hazards
Vulnerability
Disaster
• Vulnerability: likelihood that a community
will suffer, both in terms of fatalities and
physical damage, when exposed to hazards
in the environment
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Summary of terms
• Natural disaster: the event, past tense
• Natural hazard: the danger source
• Vulnerability: the impact on a humans /
community
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Metrics to describe hazard levels
Frequency
• Number of similar events
per unit time
• Example:
– On average, 4 former tropical cyclones
affect Atlantic Canada every year
• Frequency = 4 occurrences per year
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Metrics to describe hazard levels
Return period
• Length of time between similar
events
– Severe hurricanes strike the US on
average every 6 years
– This does not mean that there is a
severe hurricane exactly every
6 years!
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Frequency and return period
• Two ways to express the same facts
– Frequency and return period are the
inverse of one another
- Canada Day occurs
once a year.
- Spring & Fall heavy
rains occur twice a year
- Canada Day occurs
every 12 months.
- Spring & Fall heavy
rains come every 6
months
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Metrics to describe hazard levels
Magnitude
• Magnitude: amount of energy fuelling
a natural event
• Examples:
– Force of hurricane winds
– Amplitude of ground motion during an
earthquake
– Amount of water flowing in a river during
a flood
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Magnitude and frequency
• Low-magnitude events occur
frequently (have a short return period)
• High-magnitude events are rare
(have a long return period)
Low-­‐magnitude events
High-­‐magnitude events
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Frequency
Frequent Rare Return period Short Long
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Magnitude and frequency
• Example:
– Local floods are frequent during the
Monsoon in India, Pakistan and
Bangladesh
– The floods which affected several
million people in Pakistan in 2010
were a rare event (the largest floods
in more than a century)
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Sources of energy
fuelling natural disasters
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Classifying natural hazards
• Natural hazards can be grouped
according to source of energy fuelling
them
• This classification highlights common
causes
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Energy sources
• Four energy sources fuel the Earth’s
natural processes:
– Earth’s internal energy
– Solar energy
– Gravity
– Impact energy
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Ref.: Abbott & Samson.
Natural Disasters – Canadian Edition. Table 2.1 (3rd Ed).
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Earth’s internal energy
• Why is the center of the Earth hot?
– Decay of natural radioactive elements
• Uranium (U), Thorium (Th),
Potassium (K)
– Residual impact energy from planetary
accretion
• Miniature planets collided and “stuck”
together to create the Earth
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Solar energy
Abbott & Samson.
Natural Disasters – Canadian Edition.
Fig. 8.5 (3rd Ed).
• Energy from the Sun fuels the
hydrologic cycle
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Gravity
https://www.pexels.com/
• Gravity: force of attraction between
masses m1 and m2, separated by a
distance r
F = G m 1 m2 / r 2
G: constant
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Impact energy
• Energy released when objects collide
– Example: clapping your hands
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Global trends
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Global trend #1:
The number of great natural
disasters is increasing with time
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Geological disasters
Weather-related disasters
Ref.: Abbott & Samson.
Natural Disasters – Canadian Edition. Fig. 1.1 (3rd Ed).
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Global trend #1
• Geological disasters: constant
• Weather-related disasters:
increasing with time
– Impact of climate change
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Global trend #2:
The number of natural-disaster
fatalities is increasing with time
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Ref.: Abbott & Samson.
Natural Disasters –
Canadian Edition.
Fig. 1.4 (3rd Ed).
Note the logarithmic vertical scale
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Global trend #2
• Globally, communities are increasingly
vulnerable
– Population growth
– Development in risky areas
– Degradation of natural ecosystems
– Over-reliance on technology
• Better reporting in the media
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Global trend #3:
The number of human-made
disasters has been decreasing
in recent years
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Ref.: Abbott & Samson.
Natural Disasters –
Canadian Edition.
Fig. 1.5 (3rd Ed).
Human-made disasters
Natural disasters
• Introduction of vigorous health and safety
policies in emerging economies
• Same proactive approach could lead to a
decrease in the number of natural disasters
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Global trend #4:
Economic losses from natural
disasters are increasing with time
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Ref.: Abbott & Samson.
Natural Disasters –
Canadian Edition.
Fig. 1.6 (3rd Ed).
Insured losses
Overall losses
• In rich countries, the insurance industry
is a leader in risk mitigation
• There is no insurance in poor countries
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Canadian trends
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Canadian trend #1:
The number of natural disasters
in Canada is increasing with time
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Geological disasters
Weather-related disasters
Ref.: Abbott & Samson.
Natural Disasters – Canadian Edition. Fig. 1.8 (3rd Ed).
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Canadian trend #1
• Canadian communities are
increasingly vulnerable
– Population growth
– Development in risky areas
– Degradation of natural ecosystems
– Over-reliance on technology
• Better reporting in the media
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Canadian trend #2:
The number of natural-disaster
fatalities in Canada is decreasing
with time
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Canadian trend #2
Ref.: Abbott & Samson.
Natural Disasters – Canadian Edition. Fig. 1.10 (3rd Ed).
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Canadian trend #2
• Over the last century, Canada has
successfully reduced the number of
natural-disaster fatalities
– Improved engineering
– Long-term prevention
– Extensive disaster education
– Better warning systems
– Rapid response
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Canadian trend #3:
In Canada, economic losses are
mostly due to
weather-related disasters
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All natural disasters listed are
weather-related disasters!
Ref.: Abbott & Samson.
Natural Disasters – Canadian Edition (3rd Ed).
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Canadian trend #3
• "Impacts of recent extreme weather
events highlight the vulnerability of
Canadian communities and critical
infrastructure to climate change."
Source: From Impacts to Adaptation:
Canada in a Changing Climate (2007)
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Risk and mitigation
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Risk
• Risk = vulnerability x hazard
– A severe hazard associated with low
vulnerability has a lower risk level than
a severe hazard associated with high
vulnerability
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Seismic risk
Vulnerability
Baffin Island
Very low
Toronto
HIGH
Vancouver
HIGH
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Hazard
HIGH
Low
HIGH
Risk
Low
Moderate
HIGH
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Reducing risk
• Four pillars of emergency management
– Response
Short-term
– Recovery
Middle-term
– Mitigation
Long-term
– Preparedness
Long-term
• New term added in response to
climate change issues
– Adaptation
Long-term
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Ref.: Abbott & Samson.
Natural Disasters – Canadian Edition. Fig. 1.13 (3rd Ed).
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Response
• Immediate actions taken after a
disaster has occurred to put the event
under control
– Effective response is swift and
coordinated
– Efforts by police, medical teams and
firefighters
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Response
Example: A forest firefighter suppresses a
fire with an axe
Ref.: Abbott & Samson.
Natural Disasters – Canadian Edition.
Fig. 12.32 (3rd Ed).
– Coordination: detection, transport to site,
action
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Recovery
• Middle-term activities to put the
situation back to normal
– Not always possible or desirable to go
back to pre-disaster state
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Recovery
Rock slide of 29 July 2008
near Porteau, British Columbia.
Ref.: Abbott & Samson.
Natural Disasters – Canadian Edition.
Fig. 13.63 (3rd Ed).
Example: Removing debris after a mass
movement to reopen transport corridor
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Mitigation
• Long-term actions taken to minimize
the risk associated with a natural
hazard.
• Specifically, damage on infrastructure
• Attempt to eliminate the hazard
• Examples:
– Building protective infrastructure: dams, dykes,
floodways
– Retrofitting buildings in high-risk seismic zones
Introduction
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Photo: C. Samson
Example of mitigation: schools in Victoria,
BC, are currently being strengthen to better
withstand earthquakes
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Preparedness
• Actions taken in advance to ensure
people are ready when a disaster
strikes.
• Applied to humans and communities
• Examples: fire/evacuation drills,
emergency kits
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Ref.: Abbott & Samson.
Natural Disasters – Canadian Edition.
Fig. 1.14 (3rd Ed).
Preparedness
• Example: Preparing a home emergency kit
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Adaptation
• New term applicable mainlyl to
climate change / weather events.
• Long-term actions taken to lower risk
• Gradual adjustments towards
minimizing harm
• Examples:
– Using water resources more efficiently
– Choosing tree species less vulnerable to
storms and fires
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References
Abbott, P.L. and Samson, C. 2009 (1st Ed), 2012 (2nd Ed), 2015
(3rd Ed). Natural disasters – Canadian Edition. McGraw Hill.
Blaikie, P. et al. At risk: Natural hazards, people’s vulnerabilities
and disasters. 1994. Routledge.
Etkin, D., Haque, E., Bellisario, L., and Burton, I. 2004. Natural
hazards and disasters in Canada – A report for decisionmakers and practitioners. PSEPC Report. ISBN
0-9735436-0-4.
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References
From Impacts to Adaptation: Canada in a Changing Climate
2007. Donald S. Lemmen, Fiona J. Warren, Jacynthe
Lacroix, Elizabeth Bush, Eds. Government of Canada. 453 p.
https://www.nrcan.gc.ca/sites/www.nrcan.gc.ca/files/
earthsciences/pdf/assess/2007/pdf/full-complet_e.pdf
Canadians at risk: Our exposure to natural hazards. 2010.
D. Etkin, Ed. Institute for catastrophic loss reduction. 223 p.
https://www.iclr.org/images/Canadians_at_Risk_2010.pdf
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Interesting websites
Canadian Disaster Database, Public Safety Canada
• http://www.publicsafety.gc.ca/prg/em/cdd/index-eng.aspx
Is your family prepared? Public Safety Canada
• http://www.getprepared.gc.ca/index-eng.aspx
Natural hazards, The Atlas of Canada, NRCan
• http://atlas.nrcan.gc.ca/site/english/maps/geology.
html#naturalhazards
Canada’s Platform for disaster risk reduction
• http://www.publicsafety.gc.ca/cnt/mrgnc-mngmnt/dsstrprvntn-mtgtn/pltfrm-dsstr-rsk-rdctn/index-eng.aspx
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Interesting websites
All hazards monitor, NOAA
• http://www.noaawatch.gov/index.php
Forces of nature, National Geographic
• http://www.nationalgeographic.com/forcesofnature/
interactive/index.html
Stop disasters! A disaster simulation game from the
United Nations Strategy for Disaster Reduction
• http://www.stopdisastersgame.org/en
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