Vocab Layers Of Earth Flashcards
Alfred wegener
The scientist that proposed the theory of the continental drift. He was not taken seriously because he couldn’t prove how plates move
Aftershock
A smaller earthquake following a more powerful one
Asthenosphere
A layer of hotter, softer rock in the upper/middle mantle
Continental crust
A section of the earth that contains at least one continent, thicker and lighter than oceanic crust
Continental drift
Earths continents were once joined in a single landmass and gradually moved apart
Continental-continental collision
Occurs where two plates carrying continental crust push together
Convection
Energy transfer by the movement of a material
Convection currents
The movements within the mantle, the core heats the mantle making material rise, when it reaches the top it cools down & sinks again
Convergent boundary
Occurs where tectonic plates push together
Crust
The earths thinnest layer, solid rock, mostly oxygen and silicon
Divergent boundary
Occurs where tectonic plates move apart
Earthquake
Shaking of the ground caused by sudden movement of large blocks of rocks along a fault
Epicenter
The point on the surface right above the focus
Fault
A break or fracture in the lithosphere
Fault-block mountain
A mountain that forms because blocks of rock move up or down along normal faults
Focus
The point underground where rocks first begin to move during an earthquake
Folded mountain
A mountain that forms as continental crust crumples and bends into folds
Harry Hess
His theory of plate tectonics helped to explain continental drift
Hot spot
An area of volcanic activity that develops above a plume in the mantle
Inner core
A ball of hot, solid metals, mostly iron and nickel
Lava
Molten rock that reaches earths surface
Liquefaction
When shaking causes soil to act like liquid
Lithosphere
Earths crust and the very top layer of the mantle together
Magma
Molten rock that has not reached earths surface, it is still underground
Magnetic reversal
When the earths magnetic north & south poles switch places
Mantle
The earths thickest layer, made of hot molten rock, has plasticity
Mid-ocean ridge
Huge underwater mountain ranges marking where the sea floor is spreading apart
Moment magnitude scale
Used by seismologists to compare the size of earthquakes, the Richter scale is not as accurate
Oceanic crust
A section of the earth that is under the ocean, thinner and more dense and heavy than continental crust
Oceanic-continental subduction
Occurs when ocean crust sinks under continental crust
Oceanic- oceanic subduction
Occurs when one plate with oceanic crust sinks under another plate with oceanic crust
Outer core
A layer of liquid metals, mostly iron & nickle
Pangaea
The earths once- existent supercontinent which eventually broke apart
Plasticity
The ability of a solid to move like a liquid - able to be molded
Pryoclastic flow
A dense cloud of very hot gases and rock fragments that move downhill at high speed
Richter scale
Assigns a magnitude number to quantify the energy released by an earthquake
Rift Valley
A gap formed between two diverging plates
Seismic wave
Vibrations caused by earthquakes
Seismograph
An instrument that continuously records ground movements
Stress
Force when an object pushes, pulls or presses on another object
Subduction
Occurs when one tectonic plate sinks beneath another
Tectonic plates
Many large and small slabs of rock that our lithosphere is broken into, they fit together like a puzzle
The theory of plate tectonics
The earths lithosphere is made up of huge plates that move over the surface of the earth, floating on the asthenosphere, as plates move they affect the other plates nearby
Transform boundary
Occurs where tectonic plates scrape past each other
Tsunami
A water wave triggered by an earthquake, volcanic eruption or a landslide
Volcano
An opening in the earths crust through which molten rock, rock fragments, and hot gases erupt
