science vocab (unit 4)

mid-ocean ridges

A mountain ridge along the ocean floor

trenches

A deep valley in the ocean

sea floor spreading

The process of magma rising to the surface at mid-ocean ridges to form new ocean crust

theory of plate tectonics

The lithosphere is broken into larger plates that interact and cause geologic activity

tectonic plates

A part of the crust and uppermost mantle that moves over earths surface

divergent plate boundary

Where two tectonic plates move apart

convergent plate boundary

When two tectonic plates collide

transform plate boundary

When two tectonic plates slide past eaother horizontally

mantle convection

A type of current in the mantle where cooler, denser material sinks, and warmer, less dense material rises

ridge push

When new material at mid ocean ridges pushes older material aside,causing tectonic plate to move apart

slab pull

The pulling of tectonic plate due to gravity and subduction

earthquake

The ground shaking release of energy when a break in the crust occurs

fault

A large break in rock

focus

The exact underground point inside the Earth where an earthquake startes

seismic wave

The vibration caused by the release of energy during an earthquake

epicentre

The point on earths surface above where an earthquake starts

seismographs

An instrument that measures are records ground vibrations

magnitude

For earthquakes, a number that represents strength

volcano

An opening in earths surface where magma and other materials released

geohazard

Destructive event that results from a geological process