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Flashcards in Earth Science Deck (40):
1

Lithosphere

The outer layer of the Earth

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Asthenosphere

The upper layer of the Earth’s mantle, just below the lithosphere

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Mantle

The layer between the lithosphere and the core

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Core

The central region of the Earth

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Seismic Waves

Waves of energy that travel through the Earth’s crust caused by earthquakes

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Continental drift

Movement of the plates of the earth’s crust in relation to each other

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Pangaea

A super-continent that existed about 225 million years ago. All of the land masses at this time were joined together to create a super-continent

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Panthalassa

The vast sea surrounding the supercontinent of pagaea

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Plate tectonics

The theory concerning the movement of the continental plates

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Convection current

Circular movement the occurs when the warmer, less dense fluid particles rise and cooler, dense fluid particles sink

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Continental crust

The plates of the Earth’s crust that make up the land

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Oceanic crust

one of the types of crust that makes up the Earth's outer layer. Oceanic crust is thinner than continental crust and made up of dense, heavy rocks such as basalt.

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Boundaries

The edges of the tectonic plates

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Subduction

process in which two tectonic plates push against each other, and oceanic crust sinks below the less dense continental crust

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Destructive plate boundaries

convergent boundary where two plates collide

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Constructive plate boundaries

plate that creates new land from cooling magma

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Ocean ridges

an area where the tectonic plates move apart, allowing magma from the mantle to rise, forming underwater volcanoes and creating new oceanic crust as it is cooled and solidified by sea water

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Conservative plate boundaries

boundaries between sliding plates, like the San Andreas Fault in the United States

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Laurasia

one of the two smaller continents created when the supercontinent Pangaea broke apart about 200 million years ago

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Gondwanaland

one of the two smaller continents created when the supercontinent Pangaea broke apart about 200 million years ago

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Tremors

vibration on the Earth's surface caused by an earthquake

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Epicentre

the point on the Earth's centre directly above the site where an earthquake originates

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Focus

the point at which an earthquake begins

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Triangulation

finding a location by using at least three different sources of detection

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Seismograph

an instrument used to detect and measure the intensity of an earthquake

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Richter scale

a scale that measures the amount of energy released during an earthquake

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P-waves

compression waves that move through the Earth in the same way that sound waves move through air

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Secondary

the second set of waves to be detected after P-waves. During seismic activity, secondary waves or S-waves travel in the form of transverse waves.

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S-waves

the second set of waves to be detected after P-waves. During seismic activity, secondary waves or S-waves travel in the form of transverse waves.

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Body Waves

waves that travel through the interior of the Earth; P-waves and S-waves are said to be body waves

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Surface waves

(or L-waves) earthquake waves which travel only through the Earth's crust; they are responsible for the majority of an earthquake's destructive power

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Seismologist

a scientist who studies earthquakes

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Meltdowns

the melting of a nuclear-reactor core as a result of a serious nuclear accident

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Volcanoes

natural opening in the Earth's crust connected to areas of molten rock deep inside the crust

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Magma

a very hot mixture of molten rock and gases, just below the Earth's surface, that has come from the mantle

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Lava

mixture of molten rock and gases that has reached the Earth's surface from a volcano

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Volcanic bombs

large rock fragment that is blown out of erupting volcanoes; also known as a lava bomb

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Active

describes a volcano that is erupting or has recently erupted

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Extinct

describes a volcano that has not erupted for thousands of years and is effectively dead

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Dormant

describes a volcano that has not erupted for more than 20 years but is not considered extinct