ch25 Flashcards
a system of mountain ranges on the sea floor separated by valleys
mid-ocean range
a long narrow depression
rift valley
The boundary where two plates collide
convergent plate boundary
when a thick buoyant plate pushes a thin dense plate under itself
subduction
When the boundary of two plates that are moving apart
divergent plate boundary
plates slide horizontally passed each other
transform plate boundary
a sudden movement or vibration of the ground that occurs when rocks slip and slide along enormous cracks in the Earths crust called faults
earthquake
a crack in the Earths crust along which rock has moved
fault
A sudden release of energy as rock moves along a fault .Produces energy called seismic waves that travel in the Earth
elastic rebound
The origin of an Earthquake
focus
The point directly above the focus
epicenter
Who came up with the continental drift hypothesis
Alfred Wegener
What is the evidence for the continental drift hypothesis
The continents match up like a puzzle
Match rocks and fossils
Similar mountains and formations
what was the super continent called
Pangaea
Who came up with the seafloor spreading hypothesis
Harry Hess
How did Harry Hess discover the Seafloor spreading Hypothesis
Sonar
What did Harry Hess discover using sonar
MOR
On the Ocean Floor where is the Newest Rock
Closer to the MOR
What are the types of plate boundaries
Divergent
Convergent
Transform
how do convergent plate boundaries move
They collide
What type of boundary does subduction happen
Convergent
What are the two types of crust
Oceanic
continental
What Type of crust has to be present for volcanic activity to occur
Oceanic
If two continental crust collide what happens
mountains
If an oceanic continental crusts collide what happens
Deep sea trench and volcanoes
If two oceanic plates collide what happens
Volcanic islands
how do divergent plate boundaries move
They pull away from each other
What is a divergent plate example
The MOR is one example only oceanic
How do transform plate boundaries move
They slide passed eachother
What is the only transform plate boundary
San Andreas Fault
What plates can be transform boundaries
Two continental
What is an Earthquake
The sudden movement or vibration of the crust
Which plate boundaries have shallow earthquakes
Divergent and transform plate boudaries
Which plate boundaries have deep earthquakes
convergent plate boundaries
What types of stress are applied to rocks that cause earthquakes
Compression
tension
shear
torsion
What are the types of deformation
Elastic
plastic
What happens in elastic deformation
Deforms as stress is applied but returns to original shape after stress is gone
What happens when plastic deformation happens
Deforms when stress applied and stays deformed
How many types of seismic waves are there?
There are 3
What are the types of seismic waves
- Primary
- secondary
- surface
what are the 2 body waves
Primary waves
secondary waves
what type of wave is a primary wave
compression
What body wave moves the fastest
Primary waves
What type of materials do p waves go through
solid and liquid
what kind of material does s waves travel through
solids
what types of waves do the most damage
surface waves
what are the two scales that measure earthquakes
Richter
and Mercalli
What does the Richter scale measure
The amount of energy released
what does the mercalli scale measure
Damage
