Tectonic Plates Flashcards
What are the two types of crust?
Continental which is thick and less dense
Oceanic which is thinner and more dense
Why are plates moving?
Because of convection currents in the mantle
What is the place called where plates meet?
Plate margins
What happens at destructive plate margins?
Oceanic and continental plates move toward each other, the oceanic plate is subducted and destroyed, creating gas rich magma, where volcanoes and ocean trenches occur.
What happens at a constructive margin?
Two plates are moving away from each other, magma rises from the mantle to fill the gap and cools, creating new crust
What happens at a conservative margin?
Two plates are moving sideways past each other, or moving in the same direction but at different speeds, crust isn’t created or destroyed
What occurs at destructive plate margins?
A pool of magma forms, where it rises through the cracks in the crust called vents when the magma meets the surface it striped and forms a volcano
What is formed at a constructive plate margin?
Magma rides up into the gap created by the plates moving apart, forming a volcano
How are earthquakes formed?
They are caused by the tension that builds up at all 3 types of plate margins
How are earthquakes formed at destructive margins?
Tension builds when one plate gets stuck as it moves past the other
How are earthquakes formed at constructive plate margins?
Tension builds along cracks in the plates as they move away from each other
How are earthquakes formed at conservative margins?
Tension builds up when plates that are grinding past each other get stuck
Where do shock waves spread from?
The focus- the point in the earth where the earthquake starts. The waves are stronger near the focus and cause more damage
What is the epicenter?
The point on the earths surface straight above the focus
How are earthquakes measured?
Moment magnitude scale
