Restless Earth (2)
Fault
- gap between two plates
Focus
- Where earthquake starts
Epicentre
- Point on earth above focus
Magnitude
- Power of earthquake
Seismometer
- Measures magnitude
Richter scale
- Scale used to measure magnitude
Logarithmic scale
- Between each scale, each unit is up 10 times more powerful than the one before.
What is a collision zone?
- a type of destructive boundary
- form mountain ranges
- 2 continental plate collude, pushing up mountains
- earthquakes happen on faults in collision zones
Pyroclastic flow
- deadly clouds of hot ash and gas that sweep along at 200km/h
Lahar
- (volcanic mudslide) occurs when rain or snow mixes with ash
Ash cloud
- Ash fall builds on roofs, causing collapse.
Lava bombs
- keeps people close to each other
Land slides
- too much pressure on a certain area
Acid rain
- sulphuric acid comes out and travels into the clouds, reacts with rain, making it acidic
How do we know the centre of the earth is?
- magma comes out from volcanoes
- heat rises so must be hot in the middle
- Gravity - Friction - Heat
- Gets hotter as we dig
why is it hot?
It is hot because of radioactive decay