Y9 Tectonics Flashcards
Name the 4 layers of the Earth starting from the centre
Inner core, outer core, mantle, crust
What is a convection current?
A current of magma which rises when heated from below
Name the two types of crust
Oceanic and continental
At a constructive plate boundary…
The plates move away from each other. Magma rises in the gap and new crust is formed.
At a destructive plate boundary…
The plates move towards each other. Oceanic crust is subducted beneath the continental crust because it is denser.
At a conservative plate boundary…
The plates slide past one another, either in opposite directions or in the same direction but at different speeds.
At a collision plate boundary…
Two continental plates move towards one another. Neither can be sub-ducted as they are the same density, so both plates are forced upwards. Mountains are formed.
What is a volcano?
A mountain or hill (typically cone shaped) that has a vent through which lava erupts from the Earth’s crust.
List 2 characteristics of oceanic crust
Denser
Under the oceans
Newer
Can be subducted
List 2 characteristics of continental crust
Less dense
Forms continents
Older
Cannot be subducted
Define the term volcano
A mountain or hill, typically cone shaped, that has a vent through which lava erupts from the Earth’s crust.
What is pyroclastic flow?
A flow of gas, dust, ash and other particles that rushes down the side of a volcano after an eruption.
What is the focus of an earthquake?
The point where the energy is released in an earthquake
What is the epicentre of an earthquake?
The point on the ground directly above an earthquake
What is an aftershock?
A smaller earthquake following the main shock of a larger earthquake
