Glossary of Key Words for Restless Earth
Key Word/Term
Continental crust
Oceanic crust
Convection currents
Subduction zone
Destructive plate
margin
Constructive plate
margin
Conservative plate
margin
Composite volcano
Shield volcano
Primary effects
Secondary effects
Geosynclines
Sedimentary rocks
Ocean trench
Magma chamber
Vent
Andesitic lava
Basaltic lava
Supervolcano
Richter scale
Mercalli scale
Seismograph
Focus
Epicentre
Meaning
Layer of rock found beneath the Earth’s
continents.
Thinner, heavier layer of rock found beneath the
Earth’s oceans.
Hot currents in the Earth’s mantle which cause
tectonic plates to move.
Zone where oceanic crust sinks into the mantle
Where two tectonic plates move towards each
other
Where two tectonic plates move away from each
other – creating new land in between
Where two plates are moving side-by-side
Tall steep-sided volcano found at destructive
plate margins
Gently sloping volcano found at constructive
plate margins
First effects (of an earthquake, volcano, etc)
Later effects (of an earthquake, volcano, etc –
the “knock-on effects”)
Huge depressions (dips) in the Earth’s surface
Rocks, such as limestone and sandstone, formed
of compressed sediment
Very deep trenches found off the edge of
continents, formed by ocean plate subduction
Where molten rock (magma) is stored
underneath a volcano
Where magma escapes through a fracture or
crack in the Earth’s surface
Viscous (thick) lava which erupts from composite
volcanoes
Thin, runny lava which erupts from shield
volcanoes
A volcano that erupts with a massive volume of
material
Logarithmic scale used to measure the
magnitude (strength) of an earthquake
Scale used to classify the effects of an
earthquake
Instrument used to measure the magnitudeof an
earthquake
Point at which an earthquake starts beneath the
ground - where shock waves radiate out from
The point on the surface directly above the
focus