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

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)

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

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 ActivityEarthquakeAvalancheTsunami (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

happen2. Duration

the length of time the event lasts3. Extent

Size of area or region affected Town? Continent? Region?

Comparison and Analysis4. 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