Year 9 Earth Science
Terms in this set (36)
waves of energy that travel through the Earth's crust, caused by earthquakes
movement of the plates of the Earth's crust in relation to each other
a super-continent that existed about 225 million years ago. All of the landmasses that existed at this time were joined together to form this super-continent.
the vast sea surrounding the supercontinent of Pangaea
Structure of the earth
Solid inner core, Liquid outer core, Solid but fluid mantle, solid rocky crust.
the theory concerning the movement of the continental plates
thick layer inside the Earth, below the crust. Most of the mantle is solid rock, although the upper part is molten rock called magma.
circular movement that occurs when warmer, less dense fluid particles rise and cooler, denser fluid particles sink
the plates of the Earth's crust that make up the land
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.
process in which two tectonic plates push against each other, and oceanic crust sinks below the less dense continental crust
Destructive plate boundary
a convergent boundary where two plates collide, causing one plate to fall under the other and become melted into the mantle.
Constructive plate boundary
plate that is moving apart, creating new land from cooling magma that rises between the gap. Causes an oceanic ridge.
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
Conservative plate boundaries
A type of fault whose relative motion is predominantly horizontal.
An area in the mantle from which heat rises as a thermal plume from deep in the Earth. High heat and lower pressure at the base of the lithosphere (tectonic plate) facilitates melting of the rock
buckling of rocks caused when rocks are under pressure from both sides
a break in a rock structure causing a sliding movement of the rocks along the break
a sunken area where two blocks of crust have dropped down between faults
Block of the Earth's crust, with faults on either side, that has been pushed upwards by the forces below
a geological feature where movement along a fault is sideways—that is, where the blocks of crust slip horizontally past each other
vibration on the Earth's surface caused by an earthquake
the point on the Earth's centre directly above the site where an earthquake originates
the exact point under the Earth's surface at which an earthquake begins
an instrument used to detect and measure the intensity of an earthquake
a scale that measures the amount of energy released during an earthquake
compression waves that move through the Earth in the same way that sound waves move through air
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.
Waves that travel through the interior of the Earth; P-waves and S-waves are said to be body waves
a powerful ocean wave triggered by an undersea earth movement
natural opening in the Earth's crust connected to areas of molten rock deep inside the crust
a very hot mixture of molten rock and gases, just below the Earth's surface, that has come from the mantle
large rock fragment that is blown out of erupting volcanoes; also known as a lava bomb
Describes a volcano that is erupting or has recently erupted
describes a volcano that has not erupted for thousands of years and is effectively dead
describes a volcano that has not erupted for more than 20 years but is not considered extinct