Keywords - Earth Sciences Flashcards
Seismic waves
Waves of energy that travel through the Earth’s crust and are caused by earthquakes.
Continental drift
Movement of the plates of the Earth’s crust in relation to each other.
Pangaea
A supercontinent that existed 225 million years ago, where all of the land masses that existed were joined together.
Panthalassa
The vast sea that surrounded the supercontinent Pangaea.
Plate tectonics
The theory concerning the movement of the continental plates.
Mantle
The thick layer of magma below the crust. Most of the mantle is solid rock, although the upper part is molten rock called magma.
Convection current
A circular movement that occurs when Warner, less dense fluid particles rise and cooler, denser fluid particles sink.
Continental crust
The plates of the Earth’s crust that make up the land.
Oceanic crust
One of the types of crust that make up the Earth’s outer layer. Oceanic crust is thinner than continental crust, and made up of dense, heavy rocks such as basalt.
Ocean ridges
An area where the tectonic plates move apart, allowing magma from the mantle to rise, forming underwater volcanoes and creating new seafloor crust as it is cooled and solidified by the sea water.
Subduction
Process in which two tectonic plates push against each other, and oceanic crust sinks below the less dense continental crust.
Laurasia
One of the two smaller continents created when Pangaea broke apart about 200 million years ago.
Gondwanaland
One of the two smaller continents created when Pangaea broke apart about 200 million years ago.
Tremor
Small vibrations on the Earth’s surface, caused by earthquakes.
Epicentre
The point on the Earth’s surface directly above where an earthquake originates.
Focus
The point at which an earthquake begins.
Seismograph
An instrument used to detect and measure the intensity of an earthquake.
Richter scale
A scale that measures the amount of energy released in an earthquake.
Seismologist
A scientist who studies earthquakes.
Tsunami
A powerful ocean wave triggered by an an underwater earth movement.
Meltdown
The melting of a nuclear reactor core as a result of a serious nuclear incident.
