Plate Boundaries
Earthquakes and Volcanoes
Sea floor Spreading
Continental Drift
The Layers of the Earth
100
What are the three main types of plate boundaries?
Divergent, convergent, and transform boundaries
100
Where do most earthquakes occur?
Most occur along the edge of the oceanic and continental plates
100
What is sea floor spreading?
A theory that new magma rises through the ocean ridge and new oceanic crust is formed, later, the old crust goes down into the Asthenosphere, melting back into new magma.
100
Who developed the theory of Plate Tectonics and Continental Drift?
Alfred Wegener
100
What are the four layers of the Earth?
Crust, mantle, inner core, and outer core.
200
When two plates move together it creates a _________; What are the two types of this boundary?
convergent boundary; Convergent - Collision Boundary and a Convergent - Subduction
200
_________ usually form along the Earth's plate boundaries where magma and lava exits from weaknesses in the earth's surface.
Volcanoes
200
Who proposed that the movement of the continents was a result of sea-floor spreading?
Herman Hess
200
How do plate tectonics move?
By spreading apart, sliding by, or colliding into each other.
200
What is the name of the Earth's layer that you live on?
The crust
300
When two plates separate it forms a ________.
Divergent boundary
300
What causes an Earthquake to occur?
When plates squeeze or stretch, huge rocks form at their edges and the rocks move around with great force.
300
How is sea floor spreading caused?
It is caused by ?Convection Currents in the Asthenosphere. Hot water, air, and magma rise because of low density and sink because of high density.
300
The theory that all the continents were once joined together in one enormous land mass known as _______.
Pangaea
300
What is the largest layer of the Earth?
The mantle
400
When two plates slide past each other it creates a ________
Transform boundary
400
What are the three types of volcanoes?
Composite, Shield, and Cinder Cone volcanoes
400
What proof was there of sea floor spreading?
1) Ancient magnetism records flip-flops of earth’s magnetic field. 2) The age of the sea floor oceans are youngest at the mid-ocean ridges and oldest near the continents. 3) New ocean floor is created at mid-ocean ridges. And ocean floor is destroyed in subduction zones.
400
What is the Continental Drift theory?
That the continents eventually separated and drifted apart, forming into the seven continents we have today.
400
What is the hottest layer of the Earth?
The Inner core
500
What is a plate boundary?
There is a boundary between every two plates that interact, which is the plate boundary.
500
What is an earthquake?
An earthquake is a shaking of the earth's surface caused by the breaking and movement of large sections of the earth's rocky outermost crust (plates).
500
What three things happen at mid ocean ridges?
1) Sea floor spreading 2) The sea floor's youngest rocks are forming in the middle at the rift between the ridges. 3) Magnetic striping has been observed. The Earth’s magnetic field reverses itself every few thousand years.
500
Once these four discoveries were made, Alfred Wegener’s theory of drifting continents was accepted.
1) Demonstration of the young age and ruggedness of the ocean floor 2) Reversals of the Earth’s magnetic field on the ocean floor near the Mid-Atlantic Ridge 3) Seafloor spreading theory which introduced the concept of the reusing of the oceanic crust 4) The precise documentation that the world's earthquake and volcanic activity is concentrated along oceanic trenches and ridges
500
What are convection currents?
Convection currents are caused by the hot material at the deepest part of the mantle rising, then cooling and sinking again, repeating this cycle over and over again.
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