Term 1A - Hazards

Question 1

plate boundaries

describe what happens at a constructive plate boundary

north american plate (continental) + eurasian plate (continental)

Answer 1

Two continental plates move apart from each other. The gap between the two plates is filled by rising molten magma, shich solidifies to create new rocks on the sea bed. Over time, the layers of new rock break through the surface of the ocean.

Question 2

plate boundaries

describe what happens at a conservative plate boundary

north american plate + pacific plate

Answer 2

Two plates slide in the same direction (pacific sliding faster). The plates snag (get caught up). The pressure and tension between the plates build up and lock together. The plates eventually break, causing a sudden surge (earthquake).

Question 3

plate boundaries

describe what happens at a destructive plate boundary

nazca plate (oceanic) + south american plate (continental)

Answer 3

The two plates are pushes together and the heavier oceanic crust gets sub-ducted (sinks) beneath the lighter continental crust. The oceanic plate sticks as it tries to slide under the cont plate. Once it slips, an earthquake occurs. The friction generates heat, which melts the sub-ducted plate, This turns into magma that breaks through to create (composite) volcanos.

Question 4

plate boundaries

describe what happens at a collision plate boundary

indo-australian plate + eurasian plate

Answer 4

Two continental plates crash into each other. The collision causes an earthquake. The rocks between the plates from the earthquake get pushed up and folded.

Question 5

plate boundaries

what is the difference between oceanic crusts and continental crusts?

Answer 5

continental
- older |(most over 1500 million years old)
- less dense
- cannot sink
- cannot be renewed or destroyed

oceanic
- newer (most less than 200 million years old)
- denser
- can sink
- can be renewed and destroyed

Question 6

hazards and disasters

what is the difference between hazards and disasters?

Answer 6

a hazard is a natural event that has the potential to threaten both life and property, a disaster is the hazard actually happening.

Question 7

hazards and disasters

give an example of a hazard and a possible disaster.

Answer 7

strong wind > hurricane
rain > flood

hazard > disaster

Question 8

hazards and disasters

state why someone might choose to live in a hazardous areas.

Answer 8

• better building design can withstand earthquakes so people feel less at risk
• some people may not be aware of the risks of living close to a plate margin
• people living in povcerty have other things to think about on a daily basis - money, food, security, and family

Question 9

hazards and disasters

give 4 ways we can reduce the risk of tectonic hazards.

(MPPP)

Answer 9

• Monitor: keeping an eye out for warning signs and activity scientific equipment
• Predict: using historical evidence and monitoring - trying to predict where/when they may happen in the future
• Protect: design buildings to survive earthquakes nd think of ways to direct lava
• Plan: Identify and avoid places most at risk

Question 10

volcanoes

what is a volcano?

Answer 10

volcanoes are openings in the earth where magma forces its way through.

Question 11

what are the 3 states of a volcano and what do they mean?

Answer 11

• Active: likely to erupt again
• Dormant: sleeping, as they have erupted in the past 2000 years
• Extinct: will not erupt again

Question 12

volcanoes

what is the difference between composite and shield volcanoes?

Answer 12

composite volcanoes
- steap sides
- narrow base
- they produce violent/explosive eruptions
- alternate layers of ash+lava
- they have ‘thick’ magma
- usually at destructive plate boundaries

shield volcanoes
- gentle sides
- layers of lava
- ‘runny’ magma
- wide base
- gentle eruption
- usually at constructive plate boundaries

Question 13

volcanoes

what can come out of a (composite) volcano?

4 examples

Answer 13

• lava bombs
• ash clouds
• pyroclastic flow
• lahar

Question 14

case studies

give 2 long term impacts on Monsterrat.

Answer 14

• long time taken to rebuild homes and vital infrastructure (roads, telephone lines, etc.)
• ongoing problems of respiratory disease
• environmental damage to beaches, forests, wildlife, and more
• population decreased significantly (from 12,000 to 1,500 in the span of 6 years)

Question 15

case studies

give 2 short term impacts on Monsterrat.

Answer 15

• 19 deaths and over 100 injured
• 7 villages destroyed
• dameg to infrastructure made relief effort difficult (airport and main ports shut down)
• local health services unable to cope with the impact
• health problems due to sewage systems being affected

Question 16

case studies

why is there a volcano in Monsterrat?

Answer 16

because of the subduction (at a destructive plate boundary) of the North Atlantic plate undet the Carribean Plate

Question 17

case studies

explain how Monsterrat responded to the disaster.

Answer 17

• 5000 people evacuated to the north for safety
• UK assisted the relief and recovery (sent 40m GBP in aid relief and another 75m to assist long term development)
• Islanders were offered 2,500 GBP each to immigarte to the UK permanently
• permanent monitoring stations measuring volcanic activity all over the island

use these as points in your answer

Question 18

case studies

explain how the effects of the earthquake in Nepal were different to the earthquake in Kobe, Japan