Geography revision 2 Flashcards
(16 cards)
What is a natural hazard?
A natural hazard is an event that has the potential to cause damage, disruption, destruction and death.
Types of natural hazards
Tectonic hazards- volcanoes
Atmospheric hazards- hurricanes
Geomorphological hazards- flooding
Biological hazards- forest fires
Explain the factors that affect the risk of a natural hazard occurring.
Climate change- warmer world
Poverty- poorly constructed buildings
Deforestation- risk of flooding- trees absorb water.
Urbanisation- more people in an area increases the risk of injury and death.
Global distribution of earthquakes and volcanoes
They are found near the edge of the tectonic plate margins and the ring of fire. Random, linear, clustered.
Constructive plate boundaries
Moving away from each other e.g. North American and Eurasian plates. As the plates move apart the gap is filled by magma rising up from the mantle below. Shield volcanoes and volcanic islands e.g. Iceland. This type of movement mostly happens under the oceans.
Destructive plate boundaries
Moving towards each other e.g. Nazca and South American plates. The oceanic crust is forced under the other plate into the mantle where it melts in the subduction zone. Creates a trench. Energy build up into composite volcanoes and earthquakes.
Conservative plate boundaries
Sliding past each other e.g. North American and Pacific plate. One moves slightly slower. Pressure builds up along the fault until one plate jerks past the other causing an earthquake. The movement has also caused the land to become ridged and crumpled.
Primary and secondary effects of a tectonic hazard
Christchurch- primary- 185 dead, 100,000 properties damaged, $28 billion in damages. Secondary- 5 rugby World Cup matches cancelled, 50-100 years for the economy to recover.
Nepal- primary- 9,000 dead, 8 million affected, 1.4 million needed support. Secondary- landslides and avalanches, 250 people missing due to an avalanche in the Langtong region, landslide blocked Kali Gandaki river.
Immediate and long term responses- Christchurch
Christchurch- immediate- 7 million international aid provided, 30,000 residents provided with chemical toilets, more than 300 Australian police flew in. Long-term- 10,000 affordable homes build, NGO’s including save the children provided support, water and sewage restored by 2011.
Immediate and long-term responses- Nepal
Immediate- India and China provided over $1 billion of international aid, UK provided over 100 search and rescue responders as well as medics and disaster/rescue experts, 3 Chinook helicopters provided for the Nepali government.
Long term- Asian development bank a $3 million grant for immediate relief efforts, landslides cleared and roads repaired, over 7,000 schools rebuilt.
Reasons for living near a volcano
Farming- lava and ash from volcanic eruptions make soil very fertile so more crop cycles can be grown each year so the farmer can make a lot of money.
Reasons for living near a volcano
Fatalistic viewpoint- people aren’t
bothered as there is more effective monitoring so people receive warnings so believe they would be evacuated before the event happens.
Reasons for living near a volcano
Jobs in tourism- Tourists visit volcanoes for the spectacular views and relaxing hot springs- millions of jobs are created e.g tour guides and hotel/ bar tenders and tourists bringing money in to local economy.
What is prediction?
Using historical evidence and monitoring, scientists can make predictions about when and where a tectonic hazard may happen. Radon detectors measure gas radon gas escaping from cracks indicating and earthquake. GPS smartphones, animals, seismometers.
What is protection?
The main way to reduce the risk; designing buildings that will withstand the hazard. Divert lava because building cannot withstand lava flows. Strong building that can withstand earthquakes or a safe space to go to.
What is planning?
Being prepared and educated on what to do during and after a volcano. Avoiding places most at risk. Earthquake drills- more effective/ less likely to panic, emergency supply kits, local authorities should have an evacuation plan, people educated on how to seek safe shelter to stop building and objects falling on them, if residents aren’t able to evacuate in time.
