Plate Tectonics Flashcards
What is the internal structure of the Earth like, starting from the centre?
Inner Core
Outer Core
Mantle -> Asthenosphere + Lithosphere
Crust
What is the asthenosphere?
The upper layer of the earth’s mantle, below the lithosphere.
What are the 3 types of plate boundary?
Constructive/Divergent
Destructive/Convergent
Conservative/Transform
Explain what happens in a destructive plate boundary in terms of plates.
Oceanic plate will subduct (denser) below the continental plate. This melts the oceanic crust and causes it to rise and form a volcano. The friction between plates can cause very strong earthquakes.
Sometimes, when this happens at in the ocean, the same will happen except an island arc forms.
Explain what happens at a constructive plate boundary in terms of plates.
The two plates move in opposite directions away from each other and magma rises to fill the resulting gap, creating new crust. In the ocean, this can create a ridge or on land this can result in a volcano.
Explain what happens at a conservative plate boundary in terms of plates.
Occurs when two plates slide past each other either the same or opposite direction at different speeds
What causes plates to move?
Convection currents in the mantle.
Give an example of a:
Destructive plate boundary
Constructive plate boundary
Conservative plate boundary
Destructive: Nazca and South American plate
Constructive: Mid-Atlantic ridge
Conservative: San Andreas fault
(I won’t have included all of them)
What are the two types of volcano?
Composite volcano and shield volcano
Explain what a composite volcano is.
Steep sided and cone shaped. Made up of layers of ash and lava. Sticky lava that won’t flow very far
Example: Mount Etna
Explain what a shield volcano is.
Gently sloping sides and runny lava that will cover a large area. Gases escape easily.
Example: Loa in Hawaii
What is a magma chamber?
A large underground pool of magma
What is lava?
Magma once it reaches the surface.
What is a crater?
Bowl shaped basin at the top of volcano
What is vent?
A central tube which magma travels through
What is a secondary cone?
Eruptions from other vents may build up secondary comes on the flanks
Name 3 things that come out a volcano when it erupts.
Ash, steam and gas
What is a volcanic bomb?
Larger material thrown out by the force of eruption
What do seismometers do?
They record earth movements
What causes earthquakes?
Because of plates being under stress and it builds up enough to reach a breaking point.
What is an earthquake?
A sudden shock wave
What are two way to measure the power of an earthquake?
Richter scale and magnitude scal
What do the Richter scale and magnitude scale measure?
Measures the seismic waves during the earthquake
What measures the damage done by an earthquake?
The Mercalli Scale. Measures intensity.
What is the lithosphere?
The rigid outer layer of the Earth, made up of the crust and upper mantle.
What is a plate?
A section of the crust.
Are the inner and outer core solid or liquid?
Inner - Solid
Outer - Liquid
REMEMBER TO LEARN THE GLOBAL DISTRIBUTION OF PLATES
http://www.worldatlas.com/aatlas/infopage/tectonic.htm
What are convection currents?
Currents in the mantle (asthenosphere) that move the crust around.
What are the main differences between oceanic and continental plates?
OCEANIC • More dense • Thinner • Younger • Basalt CONTINENTAL • Less dense • Thicker • Older • Granite
