Chapter 25 Flashcards
a system of mountain ranges on the seafloor separated by the valley.
Mid-ocean ridge
a long narrow depression formed between peaks along the mid range ocean.
Rift valley
when two plates collide.
Convergent plate boundary
when a thick and bouyant continental plate meets a thin and dense ocean plate the denser plate dives beneath the continental the contient.
Subduction
two plates move apart along the ridge and the boundary between the two plates.
Divergent plate boundary
when plates side horizontally passed each other in opposite directions
Transform plate boundary
the sudden movement or vibration of the ground that occurs when rocks slip and slide along enormous cracks in the earth crust
Earthquake
a crack in earths crust along which a rock has moved
Fault
sudden release of strain energy as rock moves along a fault
Elastic rebound
the point of origin in a earthquake
Focus
the point on the earths surface directly above the focus
epicenter
who came up with the continental drift hypothesis?
Alfred Wegener
What were pieces of evidence to support his hypothesis?
- coastlines match up like puzzle pieces.
- found large land animal fossils.
- mountain ranges match up and the rocks are made up of the same composition
what was the name of the super continent?
pangia
who came up with the seafloor spreading hypothesis?
Harry hess
How did harry hess create a map of the seafloor?
he used sonar
who discovered the mid-ocean ridge
harry hess
where is the youngest rock found on the seafloor?
close to the mid-ocean ridge
what are the types of plate batteries?
- divergent boundary
- convergent boundary
- transform boundary
how do the convergent plate boundaries move?
together
subduction zone only occurs with what type of plate boundary?
conversion plate boundary
What types of plate boundaries have shallow earthquakes?
divergent and transform
Which boundaries have deep earthquakes?
convergent plate
What are the four types of stress that can be applied to rocks?
- compression stress
- tension stress
- shear stress
- torsion stress
What are the two types of deformation?
- elastic deformation
2. plastic deformation
What happends to the rock if elastic deformation occurs?
returns to its original shape when stress is released
What happends to the rock if plastic deformation occurs?
as soon as the stress is realsed it will stay the in its new shape
What types of seismic waves are there?
- primary waves(p waves)
- secondary waves(s waves)
- surface waves
Which type of wave moves the fastest?
primary wave
