Natural Hazards Flashcards
what is a natural hazard
a natural event that threatens people or has the potential to cause damage, destruction and death
hazard risk
the probability that a natural hazard may take place
natural disaster
A natural hazard turns into a natural disaster when it starts to affect people’s lives. HAZARDS COULD AFFECT LIVES BUT DISASTERS DO!!!
Biological hazard
caused by living things
Geomorphological hazard
created on the Earth’s surface
tectonic hazards
involves the movement of tectonic plates
Atmospheric hazard
created by weather conditions / made worse and more frequent by climate changes
distribution questions
overall where they are
examples!
Constructive plate boundary
- 2 plates moving apart
- when this happens, the magma from the mantle rises up to make new land in the form of flat shield volcano
- the movement of the plates over the mantle can cause earthquakes
destructive plate boundary
- oceanic and continental plate (usually)
- the plates move towards each other (due to convection currents) and this movement can cause earthquakes.
- As the oceanic plate is forced beneath the c plate, pressure builds up and when this is released an earthquake happens, as seismic waves are sent out.
- As the plates collide, the denser oceanic plate is subducted beneath the lighter continental plate
- When the plate sinks into the mantle, it melts to form magma.
- Newly formed magma is less dense than that in the mantle, and so it rises up through cracks in the crust and reaches the surface where it erupts to form volcanoes.
- If 2 continental plates collide, neither can sink and so the land buckles upwards to form fold mountains. This is called collision margin and earthquakes can occur at collision margins.
conservative plate boundary
- plates move past each other (due to CONVECTION CURRENTS)
- As the plates move, friction occurs and plates become stuck
- Pressure builds up as the plates are still trying to move
- when this pressure is released, it sends of huge amounts of energy, causing an earthquake
- NO VOLCANOES.
what are primary effects?
primary effects actually happen during the event. INITIAL IMPACT
what are secondary effects?
secondary effects happen from a short time to a long time later. AFTER EFFECTS
Drop, Cover, Hold on
Drop to the floor, cover your head, and hold on to something
What is a volcano?
an opening in the earths’s crust from which lava, ash and gases erupt.
Active volcano
A volcano which has erupted recently
Dormant volcano
A volcano which has not erupted recently but MAY erupt again.
extinct volcano
unlikely to erupt again (hasn’t erupted for over 10,000 years)
Management strategies- reducing the risk from tectonic hazards
PREDICTION
Use historical evidence and monitoring, scientists can predict when an earthquake/ volcano is about to occur. They can predict where, when and how big
Management strategies- reducing the risk from tectonic hazards
PROTECT
designing buildings that will withstand tectonic hazards.
Management strategies- reducing the risk from tectonic hazards
PLANNING
identifying and avoiding places most at risk., and making plans for if hazards occur.
Management strategies- reducing the risk from tectonic hazards
MONITORING
Using scientific equipment to detect warning signs alongside some non-scientific strategies such as monitoring animal behaviour. This means that people can be warned and so get to safe locations.
Ways to reduce protect against earthquakes
- Earthquake resistant buildings
- Regular earthquake drills
- Tsunami walls at the coast
E - Retrofitting
The addition of new technology to older buildings
E - Appropriate technology
Tech designed with consideration for the community it is intended for.
Examples:
- Using Bamboo (In Costa Rica)
- Using Straw Bales (Pakistan)
- affordable, easy to build material + available nearby
- Strong, flexible, lightweight
E - epicentre
the point on the Earth’s surface directly above the focus of an earthquake
E - building code
regulations which state how a building should be constructed in order or it to be safe.
What is cross-bracing?
To give added strength and prevent twisting
How are foundations of a building changed to protect against an earthquake?
Foundations set deep into the ground
2 other changes to a building to protect against an earthquake?
- Rubber shock absorbers
- Weight on the roof to counter the shock waves (computer controlled/ moveable)
LIC - (NEPAL 2015) facts
50% of shops were destroyed in Nepal
9000 people died and 20,000 were injured mainly due to falling buildings
HIC - JAPAN 2011 facts
An earthquake struck in 2011 measuring 9 on the Richter scale but less buildings collapsed as many buildings are earthquake proofed, using techniques like cross bracing and retrofitting. Less ppl injured, dead.
JAPAN 2011 - caused by an earthquake
15,000 people were killed in JAPANESE TSUNAMI and thousands of buildings were destroyed, leaving 350,000 homeless which has cost more than £185 bn to rebuild.
JAPAN earthquake - primary effects
- Airport in Sendai opened only 4 years ago and has now been destroyed by the tsunami
- In Rikuzentakata, 95% f buildings were destroyed, 10,000 people (half of the population) went missing and the entire town was wiped of the map.
JAPAN earthquake - secondary effects
- Debris got washed up on to beaches of other countries
- Dangerously high levels of radiation had been recorded in the water
JAPAN earthquake - immediate response
- Operation USA began working to address the needs medical aid.
- Onslaught of cold winter weather following the disaster, 1st shipment of Gap brand winter clothes was distributed to tens of thousands of people in places like Miyagi.
JAPAN earthquake - long term responses
- Recovery project will focus on the needs of the elderly community in this tsunami- impacted city.
NEPAL earthquake - primary effects
- 1.4 million ppl needed food
- 7000 schools destroyed
- 3 million ppl left homeless
NEPAL earthquake - secondary effects
- Ground shaking triggered landslides and avalanches , blocking roads and hampering relief efforts
- Avalanches on Mount Everest killed at least 19 ppl - the greatest loss of life on the mountain in a single incident.
NEPAL earthquake - immediate response
- Half a million tents needed to provide shelter for the homeless.
NEPAL earthquake - long term response
- Roads repaired and landslides cleared
- Stricter controls on building codes
Why people choose to live near volcanoes?
Tourism
Economic reason - They can make money from tourists; they can have gift shops and tour guides.
Social reason - They will have a better quality of life if they have money
Why do people choose to live near volcanoes?
Geothermal energy
Economic reason - they can use the heat from underground steam as electricity, so it’s cheaper and they save money.
Social reason - they can save the money they saved on other important things.
Why do people choose to live near volcanoes?
Being poor/ family ties
Economic reason - people can’t afford to relocate to anywhere else
Social reason - Some people’s families have lived there for many years so they don’t want to break family ties by moving away
