Chapter 1 - Natural Hazards Flashcards
Lithosphere
The uppermost layer of the earth. It is cool and brittle. It includes the very top of the mantle and above this is the crust.
Asthenosphere
Part of the earth’s mantle. It is hot, semi molten layer that lies beneath the tectonic plates
Outer core
Liquid (iron/nickel alloy)
Inner core
Solid
Continental crust
Forms the land Made of thick granite Low density Floats high on mantle Granite is less dense than the Mantle basalt 30-50 km thick
Oceanic crust
Under the oceans Very thin 1-3 miles Made of basalt rock Same kind of rock as found in the mantle More dense
Tectonic plates move because…
Of convection currents
Plumes
Convection cells where heat moves towards the surface
Bring magma to the surface
Others plumes are like columns of heat which form hot spots (Yellowstone)
Radioactive decay
Uranium, potassium, potherum are some examples
They have a time limit before they decay and release heat and energy
50%of the earth’s heat comes from this
Produces 20-30 terwatts
Unstable isotopes
Pangea
The 25 million year ago super continent
Hot spot
A place in centre of a place where magma rises. This causes the lithosphere to melt and magma pushes through the crust to form volcanoes
Queen Mary’s Peak
Shield volcano
My. Pinatibo
Composite volcano
Tsunami
The upper plate is bent under enormous stresses and when that pressure is released it causes the tsunami
When was Sendai Japan earthquake
11 mar 2011
Magnitude Sendai earthquake (Japan)
9.0
Sendai focus
30 km below convergent plate boundary
Sendai epicentre
70km from coast in Sendai Bay
Dams collapse - Sendai (primary effects(
1 dam collapsed
Sendai nuclear power station damage
2 nuclear power stations damaged
Sendai amount of damage
US $235 billion of damage with tsunami + earthquake
Sendai - people died (secondary effects)
15,900 died
Sendai people missing
2,600
Sendai people injured
6150 injured