chapter 25 Flashcards
System of mountain ranges on the seafloor separated by valleys
mid-ocean ridge
forms in between peaks along the mid ocean ridge
rift valley
where two plates collide
convergent plate boundary
a thick and buoyant continental plate meets a thin and dense oceanic plate the denser plate dives beneath the continent in a process
subduction
divergent plate boundary boundary between two plates that are moving apart
divergent plate boundary
type boundary where plates slide horizontally past each other in opposite directions
transform plate boundary
sudden movement or vibration of the ground that occurs when rocks slip and slide
earthquake
a crack in earths crust along which rock has moved
fault
release of strain energy as rock moves along a fault
elastic
point of origin for an earthquake
focus
point earths surface directly above focus
epicenter
Who came up with the continental drift hypothesis?
Alfred Wegener
What where some pieces of evidence that supported his hypothesis?
Large land animal fossils
coast lines matched up
mountain ranges matched up;and the same rock composition
What was the name of the super continent?
Pangaea
Who came up with the seafloor spreading hypothesis?
Harry Hess
What did he use to help him create a map of the seafloor?
Sonor
Who discovered the mid-ocean ridge?
Harry Hess
Where will you find younger rock?
closer to the MOR or near the MOR
What are the three types of plate boundaries?
Divergent boundary
Convergent boundary
Transform boundary
Subduction only happens with which type of plate boundaries?
convergent
tending move toward one point or approach each other
convergent
What are the two types of crust involved in plate movement?
Oceanic crust
Continental crust
what land forms can for when oceanic crust and continental crust convert?
volcanoes and deep sea trench
What land forms can be formed when to oceanic crust collide?
Hot Spots = They create islands also create deep sea trench
What land form is created when two continental collide or converge?
Mountains
what type of crust must be present for volcanoes active to occur?
oceanic crust
How do divergent plates boundaries move?
They come apart they divide
What are two examples of divergent plate boundaries?
mid ocean ridge
MOR (made up oceanic crust)
The East African Rift (made up of two continental crust)
How do transform plates boundaries move?
they slide by each other
What is an specific example of a transform plate boundary?
San Andreas fault ( two continental crusts)
nj
how do convention currents work?
- magma heats up,becomes less dense then rises
2. magma cools becomes more dense and goes down
What are the other forces that cause plate movement or helps with plate movement?
Slab pull
Ridge push
Friction
What are two types of boundaries shallow earthquakes?
Divergent and Transform
Which type of plate boundaries have deep earthquakes?
Convergent
What are the type of stresses can be applied on rocks?
compression stress
What are the two types of deformation?
Elastic Deformation
Plastic Deformation
what happens to a rock during elastic deformation?
It deforms then returns
what happens to a rock during plastic deformation?
It stays deformed
what are the seismic waves?
Primary
Secondary
Surface
which type of seismic waves move fastest?
primary
how do primary waves move?
what type of materials do do waves move in?
solids and liquids
how do secoundary waves moves?
they are trans verse
what type of materials do secondary move?
trans verese waves
which type of wave is more complex and causes the most damage?
surface waves
What are the two scales to measure earthquakes ?
Richter Scale
Mercalli Scale
what does the Richter scale tell us about an earthquake?
amount of energy released
