Natural hazards Flashcards
4 types of plate margins
Constructive
Destructive
Conservative
Collision
Layers of the earth
Crust
Mantle
Outer core
Inner core
What happens at a constructive plate margin?
Plates are moving apart
What happens at a destructive plate margin?
Oceanic and continental plate are moving together
What happens at a conservative plate margin?
Plates slide past each other in opposite direction in the same or different speeds
What happens at a collision plate?
2 continental plates pushing into eachother as they’re the same density
What do the plates move due to?
Convection currents
How does a volcano form?
Convection currents cause an oceanic plate to subduct under the continental plate. The friction in the subduction zone causes the magma to rise. The crust fills the gap causing magma to rise causing a volcano
What is the Pacific ring of fire?
One of the most famous areas for Volcanic activity
What is pyroclastic flow?
- Mixture of volcanic ash, rock and other debris
- ejected from volcanoes
What are lahars?
Mudflows made from rock debris
-forms from an eruption melting snow of the top of the volcano
Ways an earthquake will occur?
- minor tremors
- seismographs
- animal behaviour
- charts showing previous activity
- stress in rocks
What is an earthquake?
A build up of pressure from plate margins. When pressure is too much it cracks causing a focus. Energy released from the focus causes seismic waves.
What is a focus?
The place in the earth where the plates crack
What is the epicentre?
Closest place to the focus, directly above focus
