Booklet Glossary Flashcards
Seismic waves
Vibrations which travel as waves without transferring matter outputted by an earthquake.
Continental drift
The gradual movement of the continents across the Earth’s surface through geological time.
Pangaea
A single supercontinent that existed 230 million years ago.
Panthalassa
The super ocean that surrounded the super continent of Pangaea.
Plate tectonics
A theory explaining the structure of the earth’s crust and many associated phenomena as resulting from the interaction of rigid lithospheric plates which move slowly over the underlying mantle.
Mantle
The mostly solid rock that makes up most of the Earth’s interior.
Convection current
A heat driven cycle which causes the flow of magma in the mantle.
Continental crust
The relatively thick part of the crust which forms landmasses.
Oceanic crust
The relatively thin part of the crust which underlies ocean basins.
Ocean ridge
Ocean mountains on plate boundaries.
Subduction
When one plate forces underneath another on a convergent plate boundary.
Laurasia
The northern hemisphere half of the supercontinent Pangaea when it split.
Gondwanaland
The southern hemisphere half of the supercontinent Pangaea when it split.
Anticline
An upwards bend in folding rock.
Syncline
A downwards bend in folding rock.
Fault
A fracture or discontinuity in a volume of rock across which there has been significant displacement.
Rift valley
A steep-sided valley formed by the downward displacement of a block of the earth’s surface between nearly parallel faults or fault systems.
Horst
A raised elongated block of the earth’s crust lying between two faults.
Slip fault
Vertical, or nearly vertical, fractures where the blocks have mostly moved horizontally
Epicentre
The point where an earthquake originates but on the surface.
Focus
The point inside the Earth’s crust where the earthquake originates
Seismograph
Instruments which record the motion of the ground during an earthquake.
Richter scale
A base-10 logarithmic scale, meaning that each order of magnitude is 10 times more intensive than the last one, used to measure the magnitude of earthquakes.
Tremor
A weak vibration in the ground which can’t be felt by humans but can be detected by sensitive seismometers.
Volcano
A mountain or hill, typically conical, having a crater or vent through which lava, rock fragments, hot vapour, and gas are or have been erupted from the earth’s crust.
Magma
Molten rock inside the Earth’s crust.
Lava
Molten rock which has erupted onto the surface of the Earth.
Volcanic bomb
A large lump of lava which is throw out by an erupting volcano.
Fold
Rock which is bent due to the application of compressive energy.
Magnitude
The amplitude of seismic waves generated by an earthquake.
Palaeomagnetism
The study of the Earth’s magnetic field preserved in rocks.
