Geography Flashcards
(88 cards)
Name the earth structures in order
Crust
Mantle
Outer core
Inner core
Describe each layer
Crust- Solid rock, plate tectonics are found here
Mantle- Solid rock that can flow, semi-molten
Outer core- Liquid state, it is magnetic
Inner core- Very dense, solid rock due to high pressure
Who discovered Pangea, and what is it?
Alfred Wegner, Pangea is the theory that all continents were once one.
Name 2 pieces of evidence that Wegner found to support Pangea
Jigsaw fit (coastlines match)
Convectional currents (lava moving in circles)
Fossils (Ancient animals found on beaches of South America and Africa)
Patterns (Types of rock found in both continents)
What is continental drift?
Continents ‘drifting’ apart from eachother over time
What are convection currents?
Drive the movement of Earth’s tectonic plates due to the mantle.
Name 2 plates
Eurasian
Nazca plate
Where are most volcanoes and earthquakes found?
Along plate boundries
Convergent plate boundaries
Where 2 plates collide into eachother until 1 slides under the other (subduction)
What is a composite volcano?
A cone shaped volcano built up of masses of dried lava.
Conservative plate boundary
2 plates slide past eachother
How are fold mountains formed?
When 2 plates collide into eachother and rise.
Divergent plate boundary
When 2 plates move apart.
What is an earthquake?
Vibrations in the earths crust (seismic waves) caused by moving plate boundaries. Earthqukaes usually occur at Convergent and Conservative boundaries.
Speeds of secondary and primary shockwaves?
Primary- faster (across)
Secondary- slower (upwards and downwards)
What is liquification?
When the earthquake pushes the water out of the ground and creates wet mud.
What does the Richter scale measure?
The shaking of the earth
What does the Mercalli scale measure?
The intensity of an earthquake
Pyroclastic flows?
Fast moving currents of hot gas and rock. Close to the ground.
Lava flow?
Magma is pushed out the volcano and burns things.
Ash?
Fragments of lava and travel at great distances, can start fires.
Volcanic bomb?
Mass of molten rock ejected from volcano, can be thrown many kilometers
Lahars?
Violent type of mudflow made of rocks and water, travels at around 30mph
What is a volcano?
Openings or cracks in the earths lithosphere where magma from inside the earth escpaes the surface.