Unit 1: Global Hazard Patterns

Question 1

How are geophysical hazards distributed?

Answer 1

• Near plate boundaries
• plates move due to convection currents in the mantle.
• Volcanoes and earthquakes are the most common geophysical hazards to occur here.

Question 2

Name the 4 types of plate boundaries

Answer 2

1) Destructive (Convergent)
2) Convergent (Collisional)
3) Divergent (Constructive)
4) Conservative (Transform)

Question 3

Describe what happens at a convergent plate boudary

Answer 3

1) Destructive -> continental plate boundary and oceanic plate. Move towards each other. Oceanic crust is forced under the C plate as it is more dense. Crust melts and the pressure forces the magma through the crust. Volcano is formed and violent earthquakes occur. Mountains and oceanic trenches formed.
2) Collisional -> Two continental plates move towards each other. Continental cannot sink or be destroyed therefore both plates get pushed upwards. Fold mountains created. Violent Earthquakes occur.

Question 4

Describe what happens at a Divergent/ Constructive plate boundary.

Answer 4

2 plates move apart. the gap between them allows magma to rise. This cools and creates new crust when it reaches the surface. E.G. mid-atlantic ridge
Gentle volcanoes and gentle earthquakes.

Question 5

Describe what happens at a Conservative/ Transform plate boundary

Answer 5

2 Plates slide past each other. Get stuck on each other, pressure builds up between the two plates. Pressure is suddenly released and the sudden movement causes a violent earthquake. Crust isn’t created or lost. Fault lines are found at this boundary. Severe Earthquakes occur.

Question 6

Describe the pattern of hydro-meteorological hazards

Drought, Floods, Storms

Answer 6

Drought- Spread out. 1/3 of lands surface ha exposure to drought.
Floods - Flooding is a frequent hazard and is evident in some 33% of the world’s area, which is inhabited by over 80% of its population. Regional-scale, high-magnitude floods are frequent events in India/Bangladesh and China.
Storms - tropical storms - occur over the sea when its above 26oC of at least 70m depth

Question 7

What hazards is California prone to?

Answer 7

1) Earthquakes
2) Droughts
3) Tsunamis
4) Landslides
5) Volcanoes

Question 8

Explain why California is prone to Earthquakes

Answer 8

• San Andreas fault
• COnservative plate boundary
• 2-3 EQs per year
• San Fran EQ 1906 - 7.8 mag - 700 deaths

Question 9

Explain why California is prone to Droughts

Answer 9

• Caused by anticyclones. Dry sinking air means no rain
• Caused by La Nina - less evaporation, so less precipitation
• Increased wind blown from desert areas - dry air has mo moisture to cause precipitation
• Causes wildfires - fires spread quickly (Oct 2007 - killed 22 people and destroyed 1300 homes)

Question 10

Explain why Cali is prone to Tsunamis

Answer 10

• caused by large waves that can flood coastal areas
• Mainly caused by EQs inder Pacific Ocean
• EQ off alaska caused tsunami to hit Cali in 1964. Killed 12 people

Question 11

Explain why Cali is prone to Landslides

Answer 11

Can be triggered by EQs or coastal erosion or extreme rainstorms
- High in california because of building on and around steep slopes.

Question 12

Why is California prone to Volcanoes?

Answer 12

On plate boundary
Last eruption was Lassen Peak in 1915
Volcanoes are all being monitored.

Question 13

Why is California at high risk but at little vulnerability?

Answer 13

• Good infrastructure to cope with hazards
• Wealthy state so can afford to rebuild after a disaster
• Is able to educate population on what to do in the case of a disaster occurring.
• Has the correct equipment to help predict disasters

Question 14

What hazards are the Philippines prone to?

Answer 14

Volcanoes
Earthquakes
Landslides
Typhoons
Tsunamis
Droughts
Flooding

Question 15

What are the causes and impacts of Volcanoes in the Philippines

Answer 15

Near destructive plate boundary between the Eurasian and Philippine Plate. P plate is subducted under E plate.
- Mount Pinatubo - 1991 erupted - 847 killed in eruption. Disrupted agriculture of land. 2.1 million affected by it.

Question 16

What are the causes and impacts of Earthquakes in the Philippines

Answer 16

• P and E plates can become locked together

Question 17

What are the causes and impacts of Landslides in the Philippines

Answer 17

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Question 18

.What are the causes and impacts of Typhoons in the Philippines

Answer 18

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Question 19

What are the causes and impacts of Tsunamis in the Philippines

Answer 19

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Question 20

What are the causes and impacts of Droughts in the Philippines

Answer 20

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Question 21

What are the causes and impacts of Flooding in the Philippines

Answer 21

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