Download Natural Hazards, Classification and Analysis

NATURAL HAZARDS
Natural Hazards?
1. A natural disaster (physical event)



Volcanic eruption
Earthquake
Landslide
2. Human activity

Ex: coastal settlement of populations
Basically…..
A natural hazard is
a naturally occurring
event/phenomenon
that has an effect on
people
Terms to Know
Hazard - a threat (natural or human) that has the
potential to cause loss of life, injury, socioeconomic disruption or environmental
degradation.
Terms to Know
Disaster - a major hazard that causes widespread
disruption with significant demographic,
economic and environmental loss.
 The affected community needs outside help.
Vulnerability
 Vulnerability = susceptibility to injury or attack
 Human vulnerability leads to financial, structural,
and human losses.
 Natural hazards only occur in inhabited areas
 A natural disaster in an uninhabited area has little
tangible impact on people
 Natural hazards are increasing because of…
 Population growth (more people)
 Urbanization (lots of people in small spaces)
 Alteration of the natural environment (manmade
islands)
Terms to Know
Risk - the probability of a hazard event causing
harmful consequences.
Expected losses, death injury etc.
Hazards’ Human Costs
 Every year natural disasters leave…
 4,000,000 homeless
 46,000 injured
 5520 dead
 These figures do not include the recent
tsunami in Asia (273,000) and Hurricane
Katrina (1000)
Source: The International Red Cross
Natural Disaster Quotes
 Mr. Speaker, from hurricanes and floods in
Latin America to earthquakes in Asia, natural
disasters are increasingly becoming a regular
feature of life for large numbers of people
around the globe.
Earl Blumenauer
Quote to Elaborate
 a world full of competing emergencies and disasters,
it really helps if there is an international locomotive
that can help us bring attention - help us bring
resources.
Jan Egeland
 Did you know that the word "tsunami," which is now
being used worldwide, is a Japanese word? This is
indicative of the extent to which Japan has been
subject to frequent tsunami disasters in the past.
Junichiro Koizumi
Positive Effects
 natural disasters have beneficial ecological
consequences.
 rejuvenation of a coniferous forest months
and/or years after fires
 recharging of groundwater stocks after a
flood).
 benefits tend to become apparent months
or years after an extreme event
Methods of Classification
 Calculating human costs
 Impact measured by:
 loss of life (total deaths)
 number of injuries
 damage to property (replacement costs)
Methods of Classification
 Strength/size/intensity of event
 Hurricane system
 Tropical depression, tropical storm, category 1-5
 Tornado scale
 Force 1-5
 Richter scale (seismic events)
 Scale of 1-9, with 9 being cataclysmic, worldwide
event
 Epidemic, pandemic
Methods of Classification
 Regional occurrence
 Hurricane (Atlantic)
 Typhoon (Pacific rim)
 Monsoon (Asia, Africa)
 Frequency of occurrence
 Annually?
 Centenially?
Disaster Categories
 We classify natural disasters by the chief
process or sphere in which it operates
 Ex: Atmosphere, biosphere, lithosphere
 This system has three categories
Atmospheric Hazards
Cyclonic Storms (hurricane, typhoon, cyclone)
Tornado (twisters, dust devils)
Severe Storm (White Juan, Nor’easter)
Flooding (heavy rains)
Drought (lack of rain, prolonged high pressure)
Wildfire (wind, lightning)
Severe Weather (hot/cold) ex: ice storm
Biological Hazards
Infectious Disease
 HIV, H1N1, Bubonic Plague)
Parasitic Disease
 ringworm
Insect Infestation
 malaria, West Nile virus
Plant Disease
 Dutch Elm disease, blight
Geological Hazards
Slide (mud, land, rock)
Volcanic Activity
Earthquake
Avalanche
Tsunami (tidal wave)
Comparison and Analysis
 Any one disaster can be described by
analyzing various factors that determine
how great an impact it will have on people
 This system recognizes six main factors
Comparison and Analysis
1. Frequency

how often is the event likely to happen
2. Duration

the length of time the event lasts
3. Extent

Size of area or region affected

Town? Continent? Region?
Comparison and Analysis
4. Speed of onset
4. sudden, without warning, over quickly?
5. build slowly before a peak period
5. Spatial dispersion
 area likely to be affected by a particular event
6. Temporal spacing
 how hazards and disasters occur in time; are they
random or do they occur within a cycle
Earthquakes
 Earthquakes occur along the boundaries of the
tectonic plates of the earth’s crust.
 When these plates come in contact with each
other, the pressure builds up and an
earthquake occurs.
Tectonic Plates
Types of Earthquakes
Convergent Boundaries - When two plates collide
together. This created the Himalayan
mountains.
Subduction occurs when one oceanic plate goes
under a land plate. Created the Andes
Mountains.
Types of Earthquakes
Divergent - When two plates are moving apart.
Types of Earthquakes
 Transform Boundaries - when two plates slide
past each other.
 This is occurring along the San Andreas Fault in
California.
Earthquakes - Human Causes
Nuclear testing
Building large dams
Drilling for oil and gas
Coal mining
Factors Affecting Earthquake
Damage
 Strength and depth of earthquake, and number
of aftershocks.
 Population density
Factors Affecting Earthquake
Damage
 Time of Day
 Types of rock and sediments that buildings are
built on.
 Secondary hazards
 Economic development
Factors Affecting Earthquake
Damage - MEDCs vs. LEDCs
 Type of buildings - MEDCs countries tend to
have better quality buildings and insurance than
LEDCs.
 More prepared (ability to predict)
 More effective emergency services
 Funds to rebuild
 Relationships with other MEDCs