ch 25 Flashcards
A system of mountain ranges with a rift valley between them that extends around earth on the seafloor; formed where oceanic plates spread apart due to magma rising from Earths mantle.
mid-ocean range
long narrow depression formed in between the peaks along the mid-oceanic ridge.
rift valley
boundary where two plated collide, produces either subduction zones or continental collisions.
convergent plate boundary
the movement of a dence oceanic plate under a buoyant continental plate.
subduction
The boundary between two plates that are moving apart.
Divergent plate boundary
Tectonic plate boundary in witch plates side horizontally past each other in opposite directions.
Transform plate boundary
Sudden movement or vibration of the ground that occurs when rocks slip along enormous cracks in earths crust.
Earthquake
Crack in earths crust along along witch rock has moves.
Fault
The sudden release of stain energy from rock as it moves along a fault.
Elastic rebound
Point of origin for an earthquake the point from which seismic waves originate.
Focus
The point on earths surface directly above the focus of an earthquake?
Epicenter
Who came up with the continental drift hypothesis?
Alfred wegener
What are some evidence for the continental drift?
- The coastal lines match up like a puzzle peace.
- Mountain ranges with the same rock type
- Fossil
what was the super continental draft?
Pangaea
Who came up with the Seafloor spreading hypothesis?
Harry Hess
How did Harry Hess discover seafloor spreading hypotheses?
he used sonar
What did Harry Hess discover using sonar?
mid-ocean ridge
On the ocean floor where is the newer rock formed?
closer to the MOR
What are the three types of plate boundary?
- divergent boundary
- convergent boundary
- transform boundary
How do convergent plate boundaries move?
the collide together
Abduction only happens with witch type of plate boundary?
convergent plate boundaries
What types of crusts do we have?
- continental crust
2. oceanic crust
what crust has to be present for volcanic action to occur?
oceanic crust
if two Continental crust convert what will happen?
a mountain with be formed
if an oceanic crust and a Continental crust coverage what with happen?
a deep sea trench and volcanoes
what can be created when two oceanic crust come together?
deep sea trench and volcanic islands
What do hot spots create?
volcanic islands
How do Divergent Plate Boundaries move?
the move away from each other
What is an example of Divergent Plate Boundaries?
- MOR (only oceanic)
2. East Africa Rift(only continental)
How do Transform Plate Boundaries move?
They slide horizontally past each other
What is an example of a Transform Plate Boundaries?
San Andreas
What types of crust are involved with Transform plate boundaries?
only continental
What is a Convection current?
- magma heats up, becomes less dense, and rises
2. magma cools, becomes more dense, and sinks
witch plate boundaries have shallow earthquakes?
divergent and transform
witch plate boundaries have a deeper earthquake?
convergent
what are the four types of stress are applied to rock that can cause earthquakes?
- compression stress
- a tension stress
- a shear stress
- torsion stress
what are the two types if deformation?
elastic and plastic
what happens during elastic deformation?
when the stress is removed it returns to its original shape.
what happens during plastic deformation?
remains in new shape when the stress is released.
how many sizemic waves are there?
there are three seismic waves.
- primary waves
- secondary waves
- surface waves
what are the two types of body waves?
primary waves and secondary waves
what type of wave is primary wave?
compression
what is the fastest waves?
primary waves
what type of materials do p-waves travel through?
solid and liquid
what type of wave is secondary?
transverse waves
what type of material do s-waves travel through?
only solids
what types of waves do the most damage?
surface waves
what are the two scales to measure earthquakes?
- Richter
2. mercralli
what does the rchter scale measure?
the amount of energy realest
what does the macalli scale measure?
the amount of damage
