Natural hazards Flashcards
what is a natural hazard?
A natural process which could cause death, injury or disruption to humans, or destroy property and possessions.
what are the two main types of natural hazard?
- Geological (land and tectonic e.g. volcanoes and earthquakes)
- Meteorological (weather and climate e.g. tropical storms and extreme weather)
what are the different factors that affect the hazard risk?
- vulnerability (amount of exposure)
- capacity to cope (amount of aid)
- nature of natural hazards (amount of damage)
describe the structure of the earth
inner core, outer core, mantle, crust
what is the difference between continental and oceanic crust?
- Oceanic : 30-50 km thick, dense, 180 million years old, destroyed at destructive and formed at constructive
- Continental: 20-100 km thick, less dense, 3-4 billion years old, can’t be destroyed or formed
What are convection currents?
-movement in the mantle of the earth that can move tectonic plates and cause hazards
what are the four types of plate boundary?
- destructive
- conservative
- constructive
What is a destructive plate boundary?
- when oceanic and continental move together
- thicker oceanic is forced under the continental
- lots of friction, can trigger earthquakes or volcanoes
what is a conservative plate boundary?
- when two plates move against each other
- slide in opposite directions
the friction eventually is overcome and they slip past each other in a sudden movement (earthquake)
what is a constructive plate boundary?
- when two plates move away from each other
- volcanoes occur due to the gap created
- eventually new crust is formed
where are 80% of volcanoes found?
the ring of fire
what boundaries are volcanoes found?
- constructive
- destructive
what boundaries do earthquakes happen?
- destructive
- constructive
- conservative
what are some long term responses of earthquakes?
- re-house people who lost their homes
- repair or rebuild and damage caused
- reconnect broken networks e.g. electricity, water gas and communications
- if required, improve building regulations for more resistance in the future
- set up initiatives to help economic recovery
what are some primary effects of earthquakes?
- buildings, bridges and homes destroyed
- people injured or killed
- roads, railways, ports and airports damaged
- electricity cables, gas and water pipes damaged
what are some secondary effects of earthquakes?
- landslides and tsunamis
- leaking gas can cause fires
- people left homeless and die from cold
- no clean water and lack of sanitation and disease is spread
- aid and vehicles cannot get through and stops trade
- businesses damaged or destroyed, causing unemployment and loss of income
- repairs are expensive: weakens economy
what are some immediate responses of earthquakes?
- rescue trapped people and treat injured
- recover dead bodies: prevent disease
- put out fires
- set up temporary shelters
- provide temporary water and food supplies
- foreign countries send aid to the area
what are some primary effects of volcanic eruptions?
- buildings and roads destroyed
- people and animals injured of killed by lava flows and falling rocks
- crops are damaged
- water supplies contaminated by ash
- people, animals and plants suffocate by volcanic gases
what are some secondary effects of volcanic eruptions?
- mudflows (lahars) from volcanic materials mixes with water
- landslides cause more death and injury
- flooding caused by hot rick melting ice and snow. can also clog rivers
- transport networks are blocked
- people left homeless
- tourism disrupted, but increases after as people want to see volcanoes
- ash makes fields more fertile
- recovery can take a long time and can damage the economy heavily
what are some immediate responses of a volcanic eruption?
- evacuate people before the eruption if it was predicted or as soon as it starts
- provide food, water and shelter
- treat the injured
- rescue any cut off people
- foreign countries send aid
what are some long term responses to a volcanic eruption?
- repair and rebuild damage or resettle elsewhere
- repair and reconnect infrastructure
- improve, repair and update monitoring and evacuation plans
- boost the economy by attracting tourists to the volcano and its effects
what are the two types of volcano and their differences?
- composite: steep slope, tall with narrow base, flows short distances, violent and infrequent
- shield: gentle slope, low with wide base, less hot and slow flowing, hot and runny, mild and frequent
how can you measure an earthquake?
- richter scale: no limit, seisometre
- mercalli scale: measures effects, 1 to 12, based on opinion
How can risks from tectonic hazards be reduced?
Monitoring, prediction, protection and planning
