Plate Tectonics Flashcards
What are Transform Boundaries?
The boundary of two plates which slide past each other.
What are Convergent Boundaries?
The boundary of two plates which collide with each other/come together.
What are Divergent Boundaries?
The boundary of two plates which move away from each other.
What are the two hypotheses proposed for the movement of crustal plates?
- Convection currents in the asthenosphere.
- Gravity; through slab pull and ridge push.
What is the source of convection currents in the asthenosphere?
Heat, from the radioactive decay of the Earth’s core.
What causes an Earthquake to occur?
Stress that has built up within the Earth’s crust is released as energy.
What do seismometers and seismographs do?
They detect, measure and record motions of the ground, such as an earthquake.
How do scientists compare the strength of one earthquake with another?
Richter scale:
(1 - Least Severe, 10 - Most Severe)
What is the Mercalli Scale?
It is used to describe the amount of damage cause by an earthquake.
Molten rock from the mantle is called . . . when it is moving up through the Earth’s crust, and it is called . . . when on the Earth’s surface.
Magma, Lava
Where do volcanoes usually occur?
At plate boundaries and hot spots.
How do mid-ocean ridges occur?
What is their result?
What are the ages of the floor at different points?
When two oceanic plates move away at their boundaries, molten rock moves up to the seafloor.
The result is underwater mountain chains and new seafloor.
The age of the oceanic crust near the oceanic ridge is younger compared to that further apart.
