The Challenge of Natural Hazards Flashcards
natural hazard
natural process could cause death, injury or disruption to humans, or destroy property or possessions
hazard risk
the probability or chance that a natural hazard may take place
tectonic hazard
a natural hazard caused by tectonic movement
tectonic plate
- a rigid segment of the Earth’s crust which can float across the heavier, semi-molten rock below
- continental plates are less dense but thicker than oceanic plates
earthquake
a sudden or violent movement within the Earth’s crust, flowed by a series of aftershocks
volcano
an opening in the Earth’s crust from which lava, ash and gases erupt
protection
actions taken place before a hazard strikes to reduce its impact such a improving building design
primary effects
- the initial impacts of a natural event on people and property caused directly by it
- the buildings damaged by wind or a flooding by the storm surge
secondary effects
- the after-effects that occur as indirect impacts of the tropical storm
- contaminated water may lead to an outbreak of disease
immediate response
- the reaction of people as the disaster happens
- usually of several days
long-term responses
later reactions that occur in weeks, months and years after the event, rebuilding
social impact
the effects on the lives of people or community
management strategies
techniques of controlling, responding to, or dealing with an event
geological hazards
caused by land and tectonic processes (volcanoes and earthquakes)
meteorological hazards
caused by weather and climate (tropical storms, heat waves)
vulnerability
more people in an area exposed to natural hazards, the greater the probability they will be affected
capacity to cope
- the better a population can cope with an extreme event the lower the risk of them being severely affected
- HIC better able to cope because they have more moneys to afford defences
frequency
natural hazards that occur more often, have a higher risk
magnitude
more severe natural hazards tend to have the greatest effects
destructive margins
- tension builds when two plates move towards each other
- oceanic plate is sub ducted under continental plate into mantle
- melts to form magma
- plates stick, pressure builds
- pressured released with jerk (earthquake)
- magma rises (volcanoes)
constructive margins
- tension builds when two plates moving away from each other
- magma rises from mantle to fill gap
- cools and creates new crust
conservative margins
tension builds when two plates moving sideways past each other or moving in same direction but at different speeds. crust isn’t destroyed or created
example of a geomorphological hazard
flooding
atmospheric hazard
hazards created by the atmosphere (tropical storms and heavy rain)
2 examples of biological hazards
- forest fires
- diseases
primary effects of earthquakes
- builds destroyed
- people killed or injured
- bridges damaged
primary effects of volcanoes
- property and farmland destroyed
- air travel halted due to ash
- water contaminated
secondary effects of earthquakes
- blocked roads slow does rescue services
- broken gas pipes can cause fires
secondary effects of volcanoes
- economy slows
- ice melts causing floods
- tourism can increase
immediate responses of earthquakes
- rescue teams search for survivors
- put out fires
- treat the injured
immediate responses of volcanoes
- helicopters rescue those trapped
- evacuate
long term responses of earthquakes
- repair and rebuild properties and infrastructure
- improve building regulations
- install increased monitoring technology
long term responses of volcanoes
- repair and rebuild
- resettle locals elsewhere
- install improved monitoring technology
what are the economic reasons why people continue to live in areas at risk from a tectonic hazard
- geothermal energy provides cheap power
- farming from the nutrient rich soil
- tourism creates jobs
how can monitoring reduce the risks of a tectonic hazard, earthquake
- foreshocks using seismometers
- radon gas detectors
how can prediction reduce the risks of a tectonic hazard, earthquake
difficult to predict time and dates with present technology
how can protection reduce the risks of a tectonic hazard, earthquake
- buildings with rubber shock absorbers and deep foundations
- sea walls, tsunami protection
how can planning reduce the risks of a tectonic hazard, earthquake
- practice drills, duck and cover
- emergency supplies and training
how can monitoring reduce the risks of a tectonic hazard, volcano
- changes in ground detected by tilt-metres
- radon and sulphur has detected
how can prediction reduce the risks of a tectonic hazard, volcano
easier to predict than earthquakes as usually give warning signs
how can protection reduce the risks of a tectonic hazard, volcano
cannot design volcano proof buildings but can use concrete to divert leave flows
how can planning reduce the risks of a tectonic hazard, volcano
- evacuation
- exclusion zones
- education
tropical storms
low pressure weather systems with intense rain and winds
tropical storms develop between 5° and 30° north and south of the equator when…
sea temperature is 27° or higher
which way do tropical storms spin in the northern hemisphere
anti-clockwise
which way do tropical storms spin in the southern hemisphere
clockwise
facts about the centre of the storm (eye)
- up to 50km wide
- caused by descending air
- very low pressure
- light winds, no clouds, no rain
- high temperature
facts about eyewall
- there is spiralling rising air
- very strong winds (around 160km per hour)
- storm clouds
- torrential rain
- low temperature
facts about the edges of the storm
- wind speeds fall
- clouds become smaller and more scattered
- rain becomes less intense
- temperature increases
frequency of tropical storms
- oceans stay at 27° or higher for longer each year, longer period when tropical storms can form
- number of storms each year will increase
distribution of tropical storms
- as average ocean temperatures rises more oceans could be above 27°
- more tropical storms possibly at higher latitudes
intensity of tropical storms
- high sea surface temperatures, result in more evaporation snd increased cloud formation, more energy released
- storms could be more powerful
how can prediction and monitoring reduce the effects of tropical storms
- monitored using radar and satellites, computer models then calculate storms predicted path
- predicting where they are going gives people to evacuate and protect themselves and buildings
how can planning reduce the effects of tropical storms
- future developments, new houses, can avoid high-risk areas such as low-lying coastal zones
- governments can plan evacuation routes to ensure people can get away quickly
- emergency services can prepare for disasters by practising rescuing people from flooded areas
how can protection reduce the effects of tropical storms
- buildings can be designed to withstand tropical storms, also put on stilts to protects from floods
- flood defences can be build along rivers and coasted (sea walls)
impacts of strong winds
- damage properties
- disrupt transport
- uprooted trees and debris can injure or kill people
impacts of heavy rainfall
- too much rain can cause flooding, damage homes, disrupt transport and drown people
- recovering from flooding can cost millions
impacts of snow and ice
- cause injured due to slipping
- cause deaths due to the cold
- schools, business forced to shut, which can cause economic impacts
impacts of droughts
- water supplies can run low, causing economic impacts (crop failures)
- rules to conserve water have to be introduced (banning hose pipes)
impacts of thunderstorms
- heavy rain, strong winds and lightning can all occur during thunderstorms
- lightning can cause fires, can damage property and the environment, occasionally jill people
impacts of heat waves
- during long periods of hot weather, pollution builds up in air, can cause heat exhaustion or beating difficulties, which can kill people
- disruption to transport from rails bucking or roads melting cause economic impacts
- tourism may benefit from better weather
what sources can scientists use to work out how climate has changed over time
- tree rings
- ice and sediment cores
- pollen analysis
- temperature records
ice and sediment cores
- ice sheets made up of layers of ice, one layer formed every year
- scientists drill into ice to get king cores of ice
- by analysing the gas’s trapped in the layers of ice they can tell what temperature it was each year
- show evidence from at least 5 million years
tree rings
as tree grows it forms new ring each year, rings are thicker in warm, wet conditions
- scientists count rings to find age of free, thickness of each rings shows what the climate was like
- tree rings reliable source of evidence of climate change for past 10,000 years
pollen analysis
- pollen from plants gets preserved in sediment
- scientists can identify and date persevered pollen to show which species living at that time
- scientists know the conditions plants live in then so can compare plants to now and see how climate changed them
temperature records
- since 1850 global temperature records have been measured accurately using thermometers, a reliable but short term record of temperature
- historical evidence, like newspapers or weather reports can show evidence of temperatures
orbital changes
affect how much solar radiation (energy) the Earth receives, more energy means more warming
what are the variations in the way the Earth orbits the sun
- stretch- the Earth’s orbit around the Sun varies from circular to elliptical (oval-shaped) also called eccentricity
- tilt- the Earth’s axis is tilted at an angle as it orbits the Sun
- wobble- the Earth’s axis wobbled like a spinning top (precession)
these changes may have caused the glacial and interglacial cycles of the Quaternary period
volcanic activity
- major volcanic eruptions eject large quantities of material into the atmosphere
- some of these particles reflect the Sun’s rays back out to space, so the Earth’s surface cools
- volcanic activity may cause short-term changes in climate
solar output
- the Sun’s energy output isn’t constant it changes in short cycles of about 11 years and possibly hundreds of years long as well
- reduced solar output means that the Earth’s climate may become cooler in some areas
- solar output isn’t thought to have a major effect on global climate change
global atmospheric circulation develops
- sun warns the earth at the equator causing air to rise, creates a low pressure belt
- as air rises it cools and moves from the equator
- 30° north and south of the equator cool air sinks creating high pressure belt
- at the ground surface cool air moves either back to equator as trade winds or towards the poles, these winds curve bc of the earths rotation (coriolis effect)
- 60° north and south of the equator the warmer surface winds meet colder air from the poles, warmer air rises creating low pressure
- some air moves back towards equator snd the rest moves towards the poles
- at poles the cool air sinks creating high pressure, high pressure air is drawn back towards the equator
what are the social reasons why people continue to live in areas at risk from a tectonic hazard
- people want to stay with friends and family
- threat may not be great enough
- people confident that buildings will protect them from an earthquake
