Ch. 25 Flashcards
A system of mountain ranges on the seafloor separated by valleys.
Mid-Ocean Ridge
A long narrow depression formed in between peaks along the mid-ocean ridge.
Rift Valley
The boundary where two plates collide
Convergent Plate Boundary
When a thick and buoyant continental plate meets a thin and dense oceanic plate, the denser plate dives beneath the continent
Subduction
The boundary between two plates that are moving apart
Divergent Plate Boundary
Transform Plate BoundaryA type of boundary where plates slide horizontally past each other in opposite directions
Transform Plate Boundary
A sudden movement or vibration of the ground that occurs when rocks slip and slide along enormous cracks in earth’s crust and faults
Earthquake
A crack in Earth’s crust along which rock has been removed.
Fault
Sudden release of strain energy as rock moves along a fault
Elastic Rebound
The point of origin for an earthquake
Focus
The point on an Earth’s surface directly above the focus point
epicenter
Who came up with the continental drift hypothesis?
Alfred Wegener
What were some pieces of evidence to support Wegner’s hypothesis?
- Coastlines match up like puzzle pieces
- Found large land animal fossils
- Mountain ranges match up and the rocks are made up of same composition and age
What was the name of the super continent?
Pangea
Who came up with the Seafloor Spreading Hypothesis?
Harry Hess
How did Harry Hess map the bottom of the seafloor?
Sonar
Who discovered the mid-ocean ridge system?
Harry Hess
Where on the sea floor is the youngest rock going to be found.
Closest to the MOR (mid-ocean ridge)
What are the types of plate boundaries?
Divergent, Convergent, Transform
How do convergent boundaries move?
They collide
Subduction zones only occur with what type of plate boundary?
Convergent Plate Boundaries
What two types of crust are involved in plate movement?
Oceanic and Continental crust
What are the types of land forms that can be created when Oceanic and Continental crust converge?
Deep Sea Trench and Volcanoes
What land forms are created when two Oceanic crust converge?
Deep Sea Trench and Hot Spots (creates islands)
What land forms are created when two continental crusts converge?
Mountains
How do divergent plate boundaries move?
They seperate
What are the two examples of divergent boundaries?
MOR and Eastern African Rift
How do transform plate boundaries form?
They slide past each other.
What is a specific example of a transform plate boundary?
San Andreas Fault (two continental crusts)
How does a convection current work?
- magma heats up, becomes less dense, and rises
2. magma cools down, becomes more dense, and falls
What types of plate boundaries have shallow plate boundaries?
Divergent and Transform
Which boundaries have deeper earthquakes?
Convergent Plate Boundaries
What are the four types of stress that can be applied to rocks.
- Compression Stress
- Tension Stress
- Shear Stress
- Torsion Stress
What are the types of deformation?
Elastic Deformation and Plastic Deformation
What happens to the rock if elastic deformation occurs?
As soon as the stress is released it returns to its original form.
What happens to the rock if plastic deformation occurs?
As soon as the stress is released it remains in its new shape.
What types of seismic waves are there?
- Primary Waves
- Secondary Waves
- Surface Waves
Which type of seismic wave moves the fastest?
Primary Wave (P Wave)
How primary waves move?
Compression Wave
How do secondary waves move?
Up and Down
What types of material can P waves move through?
Solids and Liquids
What types of materials can S waves move through?
Only solids
Which waves are the most complex?
Surface Waves
What are the two scales that help us measure earthquakes?
The Richter Scale and Mercalli Scale
What does the Richter Scale measure?
The Amount of energy released?
What does the Mercalli scale measure?
The amount of damage caused
sphere
a round 3-dimensional object
ellipse
an elongated closed curve with two foci
