Tectonics Flashcards
Describing the pattern of volcanoes and earthquakes
Linear pattern alone plate boundaries. Anomalies = hotspots (middle of the plate)
Convergent plate boundaries
1) Nazca plate (oceanic) + South American plate (continental) moves together
2) Oceanic subducts (more dense)
3) large earthquakes (lots of friction and tension)
4) Oceanic crust melts because of friction + heat.
5) Magma moves towards the surface - convection currents
6) Volcanoes errupt
Divergent plate boundaries
1) Mid-atlantic ridge
2) Eurasian + North American plate move away from each other
3) Gap forms
4) Magma rises
5) Small volcanoes and lava solidifies and forms new land (Iceland)
Passive/conservative plate boundaries
1) San Andreas fault line
2) North American plate + pacific plate move past each other
3) There is a jerking/jolting movement (rock gets stuck)
4) Energy released at the focus causes earthquake
5) produced seismic waves
Hotspots
1) Occur mid-plate where magma rises to the surface causing a magma plume
2) Magma is less dense so it rises
3) Causes surface to dome. When magma finds a weakness, magma will erupt
4) This has to repeat before the volcano to form on the surface
5) e.g Hawaii
Reasons why people live near volcanoes
1) Religious
2) Jobs (tourism)
3) Expensive minerals found near volcanoes (Diamond and gold)
4) doesn’t often happen - they believe it will not erupt (Japan)
5) Fertile soil - oranges are grown on Vesuvius volcano
Reasons why people liver near earthquakes
1) building designs are ‘earthquake proof’
2) Do not have the money to move - LIC’s
3) Doesn’t happen often
How to measure of earthquake
1) Richter scale (magnitude)
2) Mercalli scale (impact on people/damage)
Focus
Where the rock gives way
Epicentre
Directly above the focus on the earths centre
Magnitude
Strength of the earthquake
Predicting earthquakes
1)
2)
3)
Predicting volcanoes
1)
2)
3)
Building design for earthquakes
1)
2)
Prevention of earthquakes
1) drop, cover, hold
2) disaster prevention day (1st september)
