Chapter 25 Flashcards
what is a system of mountain ranges on the seafloor separated by valleys
mid-ocean ridge
A long narrow depression that forms between peaks along the mid-ocean ridge
rift valley
The boundary were two plates collide
convergent plate boundary
When a thick and buoyant continental meets a thin and dense oceanic plate, the denser plate dives beneath the continent in the process called ____
Subduction
The boundary between two plates that are moving apart
Divergent plate boundary
The type of boundary where plates slide horizontally past each other in opposite directions
transform plate boundary
Is the sudden movement or vibration of the ground that occurs when rocks slip and slide along huge cracks in the eaths crust called fualts
Earthquacke
A crack along the earths crust along which a rock has moved
fualt
The sudden release of strain energy as a rock moves along a fault
elastic rebound
The point of origin for an earthquake
focus
the point on earths surface directly above the focus
epicenter
who came up with the continental drift hypothesis
Alfred Wegener
what are some evidence for the continental drift hypothesis
- the continents matched up like a puzzle piece
- mountain ranges with the same rock type lined up
- large land animals fossils found
what was the name of the super continent
Pangea
who came up with the seafloor spreading hypothesis
Harry Hess
how did harry Hess discover sea spreading
He used sonar
who discovered the MOR or mid-ocean ridge
Harry hess
on the ocean floor, where is the newer rock formed
closer to the MOR
what are the three types of plate boundaries
1- divergent plate boundary
2-convergent plate boundary
3- transform plate boundary
how does convergent plate boundaries move
1- they collide together
what type of boundary will subduction occur
convergent plate boundary
what types of crusts do we have
continental crust and oceanic crust
what type of crust must be present for volcanic activity to occur
Oceanic crust
if two continental crust converge what will be created
a mountain
if oceanic and continental crusts converge what two land forms can be created
deep sea trench and volcanoes
what can be created when two oceanic plates collide
volcanic islands & deeps sea trenches
what do hot spots create
volcanic islands
how do divergent plate boundaries move
they divide or move away from each other
what are examples of a divergent plate boundary
In water it would be an MOR (only oceanic crust)
On land, the East African rift ( only continental crust)
How do transform plate boundaries move
They slide horizontally past each other
what is an example of a transform plate boundary
The San-Andres fault
what is the cooling and heating cycle of magma in the earths mantle called
Convection current
what is a convection current
- magma heats up, becomes less dense, and rises
2. magma cools, becomes more dense, and sinks
which plate boundaries have shallow earthquakes
Divergent and transform
which plate boundaries have deeper earthquakes
convergent
what are the four types of stress are applied to rocks that can cause earthquakes
compression stress
tension stress
a shear stress
torsion stress
what are the 2 types of deformation
elastic deformation and plastic deformation
what happens during elastic deformation
when stress is removed it returns to its original form
what happens during plastic deformation
what stress is applied it remains in its new shape
how many types of seismic waves are there
3 types
Primary waves
secondary waves
surface waves
what are the two types of body waves
primary waves (P- waves) and secondary waves (S-waves)
What type of wave is a primary wave
A compression wave
which body wave moves the fastest
Primary waves
what type of materials do P-waves travel through
Solids and liquids
what kind of wave is the sencondary wave
transverse waves
what kind of material do s-waves travel through
Only solids
what types of waves do the most damage
Surface waves
what are the two scales used to measure earthquakes
The Richter scale
Mercalli scale
what does the Richter scale measure
The amount of energy released
What doe the Mercalli scale measure
The amount of damage
