Enquiry Question 1 Flashcards
What are the layers of the Earth?
Crust, Mantle, Outer Core, Inner Core
What is the crust?
Solid rock on the surface of the earth.
What is the mantle?
The second layer on the earth, hot and flows like a ‘thick liquid’.
What is the outer core?
Liquid iron and nickel and under huge pressures.
What is the inner core?
Solid, mainly iron and nickel
What is the oceanic crust?
Crust covered in oceans.
Always subducts under the continental crust.
Thinner than continental.
Denser.
What is the continental crust?
Crust covered in land.
Thicker.
Less dense.
What is a constructive plate boundary?
Where plates move apart from each other and magma seeps up and hardens to fill the gap and create new land.
What is a destructive plate boundary?
When plates move together and one subducts under the other and land is destroyed.
What is a conservative plate boundary?
When two plates rub against each other and move in different directions.
What is a collision plate boundary?
When continental crusts meet and push against each other and force land up to form mountains.
Who first had the theory that plate tectonics existed?
Wegener in 1915.
Where does an intra-plate earthquake occur?
In the interior of a tectonic plate, they are very rare.
Where do interplate earthquakes occur?
At plate boundaries, they are more common.
What is a hotspot?
An area created by a hot plume of magma that rises under the plate and occurs in the middle of a plate.
What is the Benioff zone?
The area under a destructive plate boundary where many deep earthquakes occur.
What is the hypocentre of an earthquake?
It is the ‘focus’ point within the ground where the energy that is stored in the rock is first released.
What are some features of a composite volcano.
tall, steep sided shape, traditional cone.
viscous (sticky) lava.
less frequent eruptions.
large eruptions.
What are some features of a shield volcano.
shallow sided, wide in shape.
runny lava.
more frequent eruptions.
smaller eruptions.
What are the three lava types.
Basaltic Lava.
Andesitic Lava.
Rhyolitic Lava.
What are the primary volcano hazards?
Pyroclastic flows.
Volcanic gas eruptions.
Lava.
Tephra and ash.
What are the secondary volcano hazards?
Lahars.
Jokulhlaup.
What are seismic waves?
Shockwaves released by tectonic movements.
What are the 4 theories explaining plate tectonic movement?
Mantle convection,
Slab pull,
Subduction,
Seafloor spreading.
What is mantle convection?
The movement of hot magma under the crust.
What is slab pull?
When newly formed oceanic crust sinks into the mantle, pulling the rest of the plate further down with it.
What is subduction?
When one plate slides under another into the magma where it melts at a destructive plate boundary.
What is seafloor spreading?
When new oceanic crust is formed under the ocean and it pushes the two plates apart.
What are the four types of waves earthquakes create?
Primary,
Secondary,
Rayleigh,
Love.
What is a primary wave?
The fastest travelling wave,
Moves through solid rock and fluids,
Pushes and pulls (compresses) in the direction of travel,
Causes the least damage.
What are secondary waves?
Slower than P waves,
Only move through solid rock,
Up and down movement,
Causes the ground to shake violently.
What are Rayleigh waves?
Only travel through the surface of the crust,
Ground is moved up and down and side to side,
Rolling motion,
Shakes the ground.
What are love waves?
Only travels through surface of the crust,
Fastest of the surface waves,
Moves side to side (horizontal) as it moves forward.
What are some secondary impacts of an earthquake?
Landslides,
Liquefaction,
Tsunamis.
How are tsunamis formed?
Landslides,
Eruptions of volcanic islands,
Sub-marine earthquakes in subduction zones.
How does a sub-marine earthquake form a tsunami?
The earthquake displaces the seas bed vertically which causes water column displacement.
The water then moves outwards in all directions from the point of displacement.
The water moves as a vast bulge in open water rather than a distinct wave.
It only forms a wave when the sea bed rises at the coast and the water is forced up as a wave.
