Plate Boundaries
What are the 3 types of plate boundaries?
Divergent, convergent and transform boundaries.
What are the 2 types of crust on the lithosphere?
Oceanic and continental crust.
Who discovered the theory of seafloor spreading?
Harry Hess.
Where are most volcanoes located?
The Pacific Ring of Fire.
Name the 3 types of faults.
Normal, strike-slip and reverse faults.
Where are divergent plate boundaries found?
They exist between two tectonic plates that are moving apart.
What is underneath the lithosphere?
The asthenosphere.
Which crust subducts into the asthenosphere during subduction and why?
Oceanic crust, because it is denser.
Name the 3 types of waves that occur in earthquakes.
Primary waves (P-waves), Secondary waves (S-waves) and surface waves.
Which type of fault occurs at divergent plate boundaries?
Normal faults.
What process occurs at divergent plate boundaries?
Seafloor spreading.
What are the mechanical properties of the asthenosphere?
Mechanically weak and ductile.
What causes new oceanic crust to form?
Rising magma from the asthenosphere cooling and turning into crust.
What causes the formation of volcanoes?
Magma works its way up to the surface of the earth and erupts. This forms ash deposits.
Which type of fault occurs at convergent plate boundaries?
Reverse faults.
What is a convergent plate boundary?
Where tectonic plates collide.
Which crust is denser, oceanic or continental crust?
Oceanic crust.
Where does seafloor spreading occur?
Mid-ocean ridges.
Which type of wave is the most destructive?
Surface waves.
Which type of plate boundary do strike-slip faults occur?
Transform boundaries.
What happens when continental crust collides with continental crust?
The formation of mountain ranges.
What 2 things heat up the Earth's core?
Remnant heat and heat from the decay of radioactive elements.
Name 3 pieces of evidence supporting Hess's theory of seafloor spreading.
Sediment thickness, magnetic striping and age of the seafloor.
What causes tsunamis?
Transform boundaries forming in the ocean.
Define a fault.
A fracture or zone of fractures between 2 blocks of rock.