GCSE 1.A - Challenge of Natural Hazards Flashcards
What is a natural hazard?
a natural process which could cause death, injury or disruption to humans, or destroy property or possessions
What is a natural disaster?
A natural hazard that has actually happened
What are the 2 main types of natural hazards?
- geological hazards
- Meteorological Hazards
What are geological hazards?
Hazards caused by land and tectonic processes
e.g. Volcanoes, earthquakes, landslides and avalanches
What are Meteorological Hazards?
Hazards cuased by weather and climate
e.g. tropical storms
What is the crust divided into?
Tectonic plates:
- Continental - Thicker and less dense
- Oceanic - thinner and more dense
Why are the tectonic plates moving?
Convection currents in the mantle
What is the place where the plates meet called?
Plate boundary/margin
What is a destructive margin?
2 Plates moving towards eachother
- Oceanic ( denser- Subducted) and continental creating gas-rich magma
- OR 2 Continental plates - fold mountains
What structures occur at destructive plate margins?
(Oceanic and Cont) - Volcanoes and ocean trenches
(2 cont) - Fold mountains
What is an example of a destructive plate boundary?
West coast of south africa - Oceanic Nazca plate subducted unter South American plate - Atacama Trench
What happens at constructive margins?
2 Plates moving **away ** from eachother
- Magma rises from the mantle to fill the gap and coolsm creating new crust
What happens at conservative Margins?
2 plates moving sideways or in the same direction but at different speeds
- Crust isnt created or destroyed
Which plate boundarys do volcanoes occur at? where else?
Destructive and constructive
- mantle hotspots
How do volcanoes form at destructive plate boundarys?
- The denser oceanic plate moves down into the mantle, where it melts.
- A pool of magma forms, which then rises through cracks in the crust called vents.
- The magma ( called lava when at surface) erupts, causing a volcano
How do volcanoes form at constructive plate boundarys?
the magma rises up into the gap created by plates moving apart, forming a volcano
What do volcanoes emit?
Lava and gases
Some emit lots of ash, which can cover land, block out the sun and form Pyroclastic flows
what is pyroclastic flow?
Super-heated currents of gas, ash and rock
How do earthquakes form at destructive plate boundarys?
Tension builds when one plate gets stuck as it moves past the other
How do earthquakes form at Constructive plate boundarys?
Tension builds along cracks in the plates as they move away from eachother
How do earthquakes form at Conservative plate boundarys?
Tension builds up when plates that are grinding past eachother get stuck
How do earthquakes form from tension in the plates?
The plates jerk past eachother, sending out shock waves
The waves spread out from the Focus
What is the focus?
The point in the earth where the earthquake starts - the waves are stronger nearer here and cause more damage
What is the epicentre?
the point on the earth’s surface straight above the focus
How are earthquakes mesured?
The moment magnitude scale
- the amount of energy released by and earthqauke
- Logarithmic scale ( x10 like pH)
What is the case study for Tectonic Hazards in contrasting countries?
New Zealand, Kaikoura 14 Nov 2016. magnitude: 7.8
Nepal, Gorkha 25th April 2015 Magnitude: 7.8
What is the GDP Per capita difference between New Zealand and Nepal?
NZ : US $40 331
NP: US $690
What is the Earthquake Primary effects difference between New Zealand and Nepal
- Deaths
NZ - 2 died and 50 injured
NP- 9000 people died and 22000 Injured - NP suffered 80x Building destruction but Nz damages cost 3.5 Billion more
- NP: Water tanks and Pipes destroyed 2 Million without access to clean wtaer and sanitation NZ: same
- NZ: 60 people provided with emergency hosuing NP: 4Million left homeless without support
What is the Earthquake Secondary effects difference between New Zealand and Nepal
- Nepal
- Lack of clean water caused Typhus outbreak, Killed around 13 people
- avalnches on mount eveerest killed 18 people - New Zealand
- Major road and railroad lines were blocked
- Tsunami caused with debri 250m inland
What is the Earthquake Immediate response New Zealand?
New Zealand:
- Tsunami warning issued quickly
- Emergency shelters provided
- 200 Most vunerable people evacuated from kaikoura by helicopter within 24 hours
- Power resoted within a few hours - temp water supplies set up
What is the Earthquake Immediate response Nepal?
- India and china sent teams to help reidents rescue people trapped by debris - lack of machineyr slowed down rescue efforts
- Previously damaged roads prevented emergency workers and aid to reach some of the injured
- Charities e.g. Oxfam provided medicine, food and temporary water supplies
- The red cross set up emergency shelters for 130000 families who had lost their homes
What is the Earthquake long-term response New Zealand?
$5.3million of funding was provided by the Kaikoura district council to help with rebuilding the town’s wtaer systems and harbour
- Most road and rail routes were repaired in 2 years
- The Kaikoura Mayoral Earthquake Releif fund was set up to help residents who couldnt afford basic supplies.
- March 2017, a permanent water main that was resilient to earthquakes was constructed
What is the Earthquake long-term response Nepal?
- Thw World Bank group Finanched $ 500 Million worth of projects to build earthquake-resistant housingm and repair roads and irrigation systems - projects are still ongoing
- Only the Roads from Nepal to Tibet was reopeed 2 years after, many roads are stil damaged
- Water supply is being restored, but many people still dont have acces to clean water
What are the positives of living near tectonic hazards?
- They’ve always lived there - family links
- In weathier countries, risk is minimised by preventions and planning
- Governmental support after earthquakes - 2001 Mount Etna, Italy support was provided
- Volcanic ash makes soil very fertile, attracting farmers - Mount Etna ideal for Grapes
- Tourism
What are the 4 main earthquake management strategies?
Monitoring
Prediction
Protection
Planning