Natural Hazards

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Natural Hazards
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Natural Hazards?

• A natural disaster (physical event)
• Volcanic eruption
• Earthquake
• Landslide
• Human activity
• Ex coastal settlement of populations

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Basically..

• A natural hazard is
• a naturally occurring
• event/phenomenon
• that has an effect on
• people

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Terms to Know

• Hazard - a threat (natural or human) that has the
  potential to cause loss of life, injury,
  socio-economic disruption or environmental
  degradation.

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Terms to Know

• Disaster - a major hazard that causes widespread
  disruption with significant demographic, economic
  and environmental loss.
• The affected community needs outside help.

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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)

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Terms to Know

• Risk - the probability of a hazard event causing
  harmful consequences.
• Expected losses, death injury etc.

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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

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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

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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

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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

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Methods of Classification

• Calculating human costs
• Impact measured by
• loss of life (total deaths)
• number of injuries
• damage to property (replacement costs)

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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

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Methods of Classification

• Regional occurrence
• Hurricane (Atlantic)
• Typhoon (Pacific rim)
• Monsoon (Asia, Africa)
• Frequency of occurrence
• Annually?
• Centenially?

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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

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Atmospheric Hazards

• Cyclonic Storms (hurricane, typhoon, cyclone)
• Tornado (twisters, dust devils)
• Severe Storm (White Juan, Noreaster)
• Flooding (heavy rains)
• Drought (lack of rain, prolonged high pressure)
• Wildfire (wind, lightning)
• Severe Weather (hot/cold) ex ice storm

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Biological Hazards

• Infectious Disease
• HIV, H1N1, Bubonic Plague)
• Parasitic Disease
• ringworm
• Insect Infestation
• malaria, West Nile virus
• Plant Disease
• Dutch Elm disease, blight

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Geological Hazards

• Slide (mud, land, rock)
• Volcanic Activity
• Earthquake
• Avalanche
• Tsunami (tidal wave)

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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

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Comparison and Analysis

• Frequency
• how often is the event likely to happen
• Duration
• the length of time the event lasts
• Extent
• Size of area or region affected
• Town? Continent? Region?

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Comparison and Analysis

• Speed of onset
• sudden, without warning, over quickly?
• build slowly before a peak period
• Spatial dispersion
• area likely to be affected by a particular event
• Temporal spacing
• how hazards and disasters occur in time are they
  random or do they occur within a cycle

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Earthquakes

• Earthquakes occur along the boundaries of the
  tectonic plates of the earths crust.
• When these plates come in contact with each
  other, the pressure builds up and an earthquake
  occurs.

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Tectonic Plates
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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.

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Types of Earthquakes

• Divergent - When two plates are moving apart.

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Types of Earthquakes

• Transform Boundaries - when two plates slide past
  each other.
• This is occurring along the San Andreas Fault in
  California.

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Earthquakes - Human Causes

• Nuclear testing
• Building large dams
• Drilling for oil and gas
• Coal mining

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Factors Affecting Earthquake Damage

• Strength and depth of earthquake, and number of
  aftershocks.
• Population density

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Factors Affecting Earthquake Damage

• Time of Day
• Types of rock and sediments that buildings are
  built on.
• Secondary hazards
• Economic development

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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