Earthquakes and Volcanoes (Plate Boundaries (Destructive ( image, Two…
Earthquakes and Volcanoes
Types of crust
Usually carries ocean
Thinner (5-10km thick)
Made up of Gabbro and Basalt
Usually caries land
Thicker (30-50km thick)
Cannot be sub-ducted
Older - Cannot be created or destroyed
Made up of mainly granite
move towards each other
The oceanic plate
under the continental plate because it is more dense.
The oceanic crust melts in the
Magma is formed and then rises because it's less dense and due to high pressure. The magma forces its way through the crust and forms a composite cone volcano on the surface.
The continental plate gets stuck on the oceanic plate and then buckles and crumples to form fold mountains
Earthquakes can form here due to the oceanic plate rubbing against the continental plate as it subducts. This build up pressure and friction and when released can cause an earthquake.
Two plates move
past each other
(opposite, or same direction.
The plates get stuck, and
This builds up
within the plate.
then gets too much and suddenly released, the plates '
slip past each other
as shockwaves from the
(point at which the pressure is released).
These shock waves cause the plates to
/vibrate causing an earthquake.
No volcanoes = no magma, no subduction or rising magma.