Geography - Tectonics Flashcards
(9 cards)
What is the structure of the earth and what are the properties of each layer?
Crust - 5-70kmthick, solid rock broken into pieces called tectonic plates
Mantle - Thickest layer, semi molten
Outer core - 2300km thick, Liquid iron that creates our magnetic fields
Inner core - 1250km thick, made of iron and nickel and due to pressure, it is solid.
What was Wegner’s theory and can you explain 2 pieces of evidence
Tectonic plate theory.
Jigsaw fit: Africa and South America appear to fit and so do other coastlines of other continents
Convection currents: Hot rock rises and spreads in two directions, through this process the earth’s crust moves
Fossil theory: On the coasts of Africa and South America, there has been a rare land reptile discovered, the mezasaouras
Names of major plate boundaries
Eurasian plate
North American plate
Juan de fuca plate
Cocos
Pacific
Nazca
African
Indo-Australian
Why are earthquakes and volcanoes found at plate boundaries?
They are found at plate boundaries as the ground is constantly moving either away or towards each other, shaking the earth and forming either shield or composite volcanos
What are convection currents?
Convection currents are where hot rock in the mantle rises up and splits up in two directions, moving the earth’s crust
What happens at convergent boundaries?
The tectonic plates are moving at each other, this causes composite volcanoes and earthquakes
What happens at divergent plate boundaries?
The tectonic plates moves away from each other, forming earthquakes and shield volcanoes
One example of a tsunami is…
The 2004 Indian Ocean Tsunami
What are the causes of a tsunami?
Underwater earthquakes that displace the water at the surface sending a surge of water to the coast.
