Topic 1 - Earthquakes + Case Study (set C)✔️ Flashcards
What boundary’s do earthquakes form at?
- Convergent
- Divergent
- Conservative
How do earthquakes form at convergent plate boundaries?
Tension builds up when one plate gets stuck as its moving past
How do earthquakes form at divergent plate boundaries?
Tension builds up along cracks within the plates as they move away from each other
How do earthquakes form at conservative plate boundaries?
Tension builds up when plates that are grinding past each other get stuck
What happens when the plates eventually jerk past each other?
Huge release of tension sends out shock waves which are earthquakes which are measured using moment magnitude scale
What is the focus?
Point in the earth where the earthquake starts - deeper the focus - less damage at the surface as the shock waves travel through more rock which reduces their power
What is the epicentre?
Point above the focus on the earths surface
How do earthquakes cause tsunamis?
Earthquakes cause the seedbed to moves which displaces water the depth of the earthquake affects the size of the tsunamis - deeper less powerful so a smaller wave
What was the Japanese earthquake? What did it cause?
earthquake struck north-east japan it measured 9.0 on the moment magnitude scale and triggered a tsunami - focus was 30km below the seabed and the epicentre was 130km east of Sendai coast
What was the Haiti earthquake?
earthquake measuring 7.0 on the moment magnitude scale struck Haiti - it had a shallow focus of 13km and an epicentre 25km south west of the capital Port-au-Prince
3 Primary effects of the Japanese earthquake?
- 1 dam collapsed , 2 nuclear power stations damaged and oil refinery’s set on fire
- motorway, airport and railways damaged
- 235 billion dollars of damage
3 Secondary effects of the Japanese earthquake caused by the tsunami?
- 15,900 dead and 350,000 homeless
- two nuclear reactors went into meltdown
- education, employment and business effected greatly
3 Primary effects of the Haiti earthquake?
- 316,000 dead and 300,000 injured
- 1,000,000 homeless - due to poorly built houses collapsing
- port, communication links and major roads were damaged due to collapsed buildings
3 Secondary effects of the Haiti earthquake?
- water supply system destroyed and a cholera outbreak caused 8000 deaths
- port was destroyed so getting aid to the area was hard
- factories important to Haiti’s economy (producing clothes) were damaged resulting in 1 in 5 jobs being being lost
How can countries like Japan better prepare for earthquakes through long-term planning? Give 3 ways?
- earthquake drills, involving emergency services who practice rescuing people
- people keep emergency kits, radios, food and water at home
- many buildings are earthquake proof - so they will sway but not collapse and the gas supplies will shut off to stop fires
How did Japan benefit from its long-term planning when the earthquake struck?
- Japanese authorities gave an advanced warning before the earthquake and tsunami struck
- not a single building in Tokyo collapsed due to their design
- nobody died on the bullet trains due to their automatic braking system
3 Features of Japans short-term relief to the earthquake?
- international aid and search and rescue teams were brought in quickly
- workers and soldiers helped with the aftermath
- transport and communications were restored alongside power supplies
3 Features of Haiti’s short-term relief to the earthquake?
- emergency aid was slow due to damage of government buildings
- international aid and search and rescue teams were flown in to help trapped people
- money and aid was donated
what caused the Japanese earthquake?
it was caused by the pacific plate being subducted under the Eurasian plate at the Japanese trench
why was the Japanese earthquake dangerous?
scientists had not predicted one of this scale - was a 9.0 on the magnitude scale
what caused the Haiti earthquake?
caused by the conservative plate boundary between north American plate and Caribbean plate
