Earth Science- CH8 Flashcards
Lithosphere
the tough, outer part of the earth, consisting of the crust and upper mantle
Ashenosphere
the upper layer of the earth’s mantle, below the lithosphere, in which it is made up of plastic
Mantle
the region of the earth’s inside between the crust and the core, believed to consist of hot, dense silicate rocks/lava
Core
The very bottom of Earth’s interior consisting of both the inner and outer core. This is where the hottest part of the earth.
Seismic Waves
Waves of energy that travel through the Earth’s crust, caused by Earthquakes
Continental Drift
movement of the plates of the Earth’s crust in relation to each other
Panthalassa
the vast sea surrounding the supercontinent of Pangaea
Pangaea
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.
Plate Tectonics
the theory concerning the movement of the continental plates
Convection currents
circular movement that occurs when warmer, 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 makes up the Earth’s outer layer. Oceanic crust is thinner than continental crust and made up of dense, heavy rocks such as basalt.
Boundaries
the edges of tectonic plates
Subduction
process in which two tectonic plates push against each other, and oceanic crust sinks below the less dense continental crust
Destructive plate boundaries
a convergent boundary where two plates collide
Constructive plate boundaries
plate that creates new land from cooling magma
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
Conservative plate boundaries
boundaries between sliding plates, like the San Andreas Fault in the United States
Laurasia
one of the two smaller continents created when the supercontinent Pangaea broke apart about 200 million years ago
Gondwanaland
one of the two smaller continents created when the supercontinent Pangaea broke apart about 200 million years ago
Hotspots
a localised place where an activity occurs
Tremors
vibration on the Earth’s surface caused by an earthquake
Epicentre
the point on the Earth’s centre directly above the site where an earthquake originates
Focus
the point at which an earthquake begins
Triangulation
finding a location by using at least three different sources of detection
Seismograph
an instrument used to detect and measure the intensity of an earthquake
Richter Sclae
a scale that measures the amount of energy released during an earthquake
Primary Waves
compression waves that move through the Earth in the same way that sound waves move through air
Secondary Wave
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.
Body Waves
waves that travel through the interior of the Earth; P-waves and S-waves are said to be body waves
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
Seismologists
a scientist who studies earthquakes
Tsunami
a powerful ocean wave triggered by an undersea earth movement
Volcanoes
natural opening in the Earth’s crust connected to areas of molten rock deep inside the crust
Magma
a very hot mixture of molten rock and gases, just below the Earth’s surface, that has come from the mantle
Lava
mixture of molten rock and gases that has reached the Earth’s surface from a volcano
Volcanic Bombs
large rock fragment that is blown out of erupting volcanoes; also known as a lava bomb
Lava Bombs
see volcanic bomb
Active
describes a volcano that is erupting or has recently erupted
Extinct
describes a volcano that has not erupted for thousands of years and is effectively dead
Dormant
describes a volcano that has not erupted for more than 20 years but is not considered extinct
