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Geography unit 1
13. Floods, earthquakes and volcanoes as hazards
Question | Answer |
---|---|
Human beings live all over the world even in hazardous areas, since the | positive aspects may outweigh the potential hazards. |
Extreme events which occur in uninhabited areas of the world are | not hazards. |
the most common hazard experienced globally and throughout the Caribbean | floods |
the most sudden hazard in onset, striking with little warning | Earthquakes |
earthquakes may cause Tsunamis by | undersea earthquakes and flood coastal areas |
the most dramatic extreme natural event | Volcanoes |
Hazard risk arises from | the intersection of 'natural events' and 'vulnerable population' |
what influences the impacts of hazard risks | -The magnitude, speed, extent and duration of the natural event -characteristics of the human environment -frequency of the event |
how the magnitude of a hazard affects the risks | the greater the size of the event; the greater the hazardous effects |
how populations in LDCs respond to hazards | Populations in LDCs are often unprepared and ill equipped to respond to hazard impacts. Many lives are lost and it is often difficult for communities to return to previous living standard |
how populations in MDCs respond to hazards | there are greater property losses than loss of life as higher levels of technology and resources allow more people to prepare, evacuate or recover from the effects of hazards |
example of how a hazard in MDCs was different from in a LDC | flooding of the Mississippi river in the USA has a different level of impact from flooding in the Ganges delta where the population is larger and more vulnerable |
The magnitude of an event will influences the impacts of hazard risks | directly influence its impact: the greater the size of the event, the greater the hazardous effects. |
Generally people are better prepared for hazards if | they have experienced an event. Planned land use zoning and evacuation may lessen the impact |
speed of onset of floods | moderate |
speed of onset of earthquakes | fast |
speed of onset of volcanoes | moderate |
duration of floods | Days/weeks |
duration of earthquakes | Seconds |
during of volcanoes | Days |
areas of flood | Widespread |
areas of earthquakes | Concentrated |
areas of volcanoes | Limited |
Each natural hazard can have primary, secondary and tertiary effects depending on | the characteristic of the population and the level of development |
primary effects of hazards are those caused | directly by the event - for example, flood waters may sweep away houses, or earthquakes may cause buildings to collapse. |
secondary effects of hazards are those in | the aftermath of the event, for example, famine, disease or fires after the event is over |
tertiary effects of hazards are | long term/permanent changes, for example, relocation of settlements |
eg of a case study of flooding | Guyana |