The restless earth Flashcards
What are the four layers of the earth?
Inner core, outer core, mantle, lithosphere/crust
What is the crust/lithosphere divided into?
Tectonic plates
Why do the tectonic plates move?
Due to convection currents in the mantle they float on
What is a constructive plate margin?
Where two tectonic plates are moving apart; causing cracks in the crust where a gap is forming; magma rises up into cracks to form new crust
What hazards are found at constructive plate margins?
Volcanoes and earthquakes
What is a destructive-subductive plate margin?
Where and oceanic plate is forced underneath a continental plate; the oceanic plate is destroyed as is it melts to form magma
What hazards are found at destructive-subductive plate margins?
Volcanoes and earthquakes
What is a destructive-collision plate margin?
Where two continental plates move towards each other and collide.
What hazards occur at destructive-collision plate boundaries?
Earthquakes
What is a conservative plate margin?
Where two plates slide past each other; they move at different angles and speeds- causing sticking
What hazards occur at conservative plate margins?
Earthquakes
What are the characteristics of oceanic crust?
Newer (most less than 200 million years old) , thinner (5-10 km thick), denser (more basalt in it), can sink, can be renewed and destroyed
What are the characteristics of continental crust?
Older (most over 1500 mil yrs old), thicker (20-70 km), less dense (more granite in it), cannot sink, cannot be renewed or destroyed
What is the difference between the focus and the epicentre?
The focus: where the pressure build up has occurred (underground) between the plates
The epicentre: point on the crust directly above the focus, from which seismic waves radiate out
What is a seismograph?
The machine that measures the size/magnitude of the waves
When did the Haiti earthquake occur?
12th January 2010
What % of people in Haiti live in poverty and what % have access to clean water? (pre-earthquake)
80% of Haitian people lie in poverty
46% have access to clean water (not even half)
Where is Haiti?
An island in the Caribbean, (half of the island is the Dominican republic); it is found in the South American continent
What is the average life expectancy in Haiti? how many people per doctor?
Average life expectancy: 62 yrs old (1/2 pop. under 18)
People per doctor: 1000 people per 0.25 doctors
Where was the epicentre and focus of the Haiti earthquake?
Epicentre: 25 km from Haitian capital Port-au-Prince
Focus: only 13 km underground
What were 4 direct impacts of the earthquake in Haiti?
34/37 of doctors in Port-au-prince were killed, 1/3 buildings destroyed, 300,000 people left homeless, 230,000 (approx.) killed directly
What were 4 indirect impacts of the earthquake in Haiti?
5 years later people still living in tents in capital, Nov. 2010 cholera outbreaks, over 300,000 killed by cholera, only 2% of $1 million relief funds raised for Haiti released, Haitian tourism decline
What were 3 short term responses of the Haiti earthquake?
3/4 damaged buildings inspected and repaired, 200,000 received food or cash for public work (e.g. clearing rubble), 2000+ helped by Dominican republic emergency team
What were 2 long term responses of the Haiti earthquake?
World bank pledged $100 mil to support reconstruction/recovery programmes, red cross & UN remained in Haiti to help- stayed for 2 yrs & built long term shelters
When did the Japan earthquake begin?
11th March 2011
What was the rating of the Japan earthquake?
The earthquake was a 9 on the Richter scale
How strong was the Japan earthquake?
It was the force of 2 million Hiroshima bombings happening simultaneously
Where was the focus of the Japan earthquake?
Only 30 km underground
Where was the epicentre of the Japan earthquake?
130 km away from the city of Sendai