Natural Hazards

Question 1

Describe the distribution of earthquakes?

Answer 1

• happen along all three plate margins

Question 2

Describe the distribution of volcanoes?

Answer 2

destructive and constructive plate boundaries

Question 3

What are the three types of plate margin?

Answer 3

destructive, constructive and conservative

Question 4

What are the two types of crust?

Answer 4

continental and oceanic

Question 5

Describe continental crust?

Answer 5

thicker (30-50km) and less dense

Question 6

Describe oceanic crust?

Answer 6

thinner (5-10k) and more dense

Question 7

Why are plates moving?

Answer 7

due to convection currents in the mantel underneath the crust

Question 8

What are plate boundaries or margins?

Answer 8

the place where plates meet

Question 9

Describe destructive margins?

Answer 9

two plates moving towards each other

oceanic and continental plate are moving towards each other due to convection current processes in mantle

when they meet the denser oceanic plate is subducted (forced beneath) the lighter continental plate. Earthquakes occur along the subduction zone

increased heat and pressure causes oceanic crust to melt and is destroyed forming a magma chamber

build up of pressure and gas forces magma to surface as a volcanic eruption

Question 10

Describe constructive margins?

Answer 10

two plates moving away from each other.

• convection currents in mantle rise upwards and outwards causing plates above to be pulled apart
• as they pull apart a gap is created between plates
• this is then filled by rising magma from the mantle, which plugs the gap, cooling to form new crust
• overtime this builds up to form a volcano and becomes a volcanic island if high enough- often happens under the oceans

Question 11

Describe conservative margins?

Answer 11

where two plates are moving sideways past each other at different speeds.

as they move they get stuck causing friction and pressure to build up

this mounting energy is then released as an earthquake

Question 12

Explain in basic terms how a volcano is formed?

Answer 12

• oceanic plate moves down into mantel where destroyed and melted
• pool of magma forms
• magma rises through cracks in the crust called vents
• magma erupts onto surface causing a volcano

Question 13

Explain in basic terms how an earthquake is formed?

Answer 13

• when two plates get stuck

- this causes pressure to build up and when this pressure is released an earthquake occurs

Question 14

What is the focus of an earthquake?

Answer 14

the point in the earth where the earthquake starts

Question 15

What is the epicentre?

Answer 15

the point on the earths surface straight above the focus

Question 16

Where is a HIC that suffered through an earthquake?

Answer 16

Chile

Question 17

What is a LIC that had an earthquake?

Answer 17

Nepal

Question 18

What were the immediate responses in Chile?

Answer 18

• emergency services acted swiftly
• temporary repairs made to important Route 5 north-south highway within 24 hours
• aid was able to be transported to affected areas
• power restored to 90% of homes within 10 days
• national appeal raised $60 million

Question 19

Using one word per point what are the immediate responses in Chile?

Answer 19

• emergency services
• temporary repairs
• power and water restored
• $60 million raised

Question 20

What were the immediate responses of Nepal?

Answer 20

• Search and rescue teams arrived quickly from countries such as UK, India, China
• helicopters rescued many people caught in avalanches on Mount Everest
• half a million tents needed to provide shelter for homeless
• financial aid pledged from many countries
• field hospitals set up to support overcrowded main hospitals
• 300,000 people migrated from Kathmandu to seek shelter and support with family and friends
• social media was used widely to map damaged areas

Question 21

Using one word per point what are the immediate responses in Nepal?

Answer 21

• helicopters- avalanches
• search and rescue teams
• water and medical support-other countries
• tents
• financial aid
• field hospitals
• migration occured
• social media

Question 22

What are the long term responses in Chile?

Answer 22

• month after earthquake, Chile’s government launched a housing reconstruction plan to help nearly 200,000 households affected
• Chile’s strong economy could be rebuilt without the need for much foreign aid
• President announced it could take years for Chile to recover fully from damaged buildings and ports

Question 23

What are the long term responses in Nepal?

Answer 23

• roads repaired
• landslides cleared
• thousands of homeless people to be re-housed and damaged homes repaired
• 7,000 schools to be re-built/ repaired
• tourism to be boosted
• repairs to Everests base camp and trekking routes
• stricter controls on building codes

Question 24

definition of an earthquake

Answer 24

-the shaking and vibration of the Earth’s crust due tp the movement of the Earth’s plates

Question 25

definition of an volcanoes

Answer 25

-an opening in the Earth’s crust through which magma, molten rock and ash are erupted onto land