Restless planet Flashcards
Earthquake
The shaking of the Earth’s crust, caused by sudden rock movements.
Fault
A crack in rock, where blocks of rock can move relative to each other.
Focus
The point where the seismic waves of an earthquake started.
Epicentre
The point directly above the focus on the Earth’s surface.
Fold mountain
Formed by plates pushing into each other; the rock at the plate edges gets folded upwards, making mountains.
Lava
Melted rock at the Earth’s surface.
Magma
Melted rock below the Earth’s surface.
Magnitude
How much energy an earthquake gives out (measured on the Richter scale).
Plates
The Earth’s hard outer part is broken into big slabs called plates, which move around causing earthquakes.
Pacific ring of fire
The ring of volcanoes and earthquakes sites circling the Pacific Ocean.
Volcano
Where lava erupts at the Earth’s surface.
Convection currents
Powerful currents of flowing magma, in the mantle, that move in a circular motion, that causes plates to move.
Strain energy
Pressure stored by rocks when two huge masses of rock converge.
Seismic waves
When strain energy is released in waves; these seismic waves pass through the Earth in all directions, shaking everything.
Aftershocks
Smaller earthquakes that occur as the rock settles in its new position.
