Tectonics Flashcards
Describe pattern of volcanoes and earthquakes.
1) Plate boundaries
2) Linear pattern
3) Anomalies (hotspots)- middle of plates
4) (Often along the coast)
Divergent plate boundaries
1) Plates move away from each other.
2) Gap created
3) so magma rises
4) Magma then solidifies and creates volcanoes and new 5) land. — gentle volcanoes
eg. Iceland
6) Atlantic ocean- mid atlantic ridge line
7) Eurasian plate and the North American place are moving away from each other
Convergent plate boundaries
1) Plates move towards each other and collide.
2) Nasca plate (oceanic) moves towards South American 3) plate (continental)
4) One is oceanic, One is continental
5) Oceanic is more dense continental is less dense
6) oceanic subduct because it is more dense
7) The two plates rub and get heat (first) friction (next)
8) The friction and rubbing creates big/ high magnitude earthquakes
9) The heat melts the rock becoming molten rock/ magma
10) Magma rises
11) Violent eruption on surface- volcano
12) Fold mountains- can push mountains up
Conservative plate boundaries
1) San Andreas fault line
2) North American plate and the Pacific plate move past each other
3) This is a jolting/jerking/sudden movement doesn’t happen without rock getting stuck
4) release energy from the focus is called an earthquake
5) releases seismic waves
Hotspots
1) mid plate magma moves to the surface called a magma plume
2) the magma is less dense than the surrounding mantle
3) it causes the surface to dome and when the magma finds a weakness in the rock it will erupt on the rock on the surface.
4) has to repeat before you see the volcano on the surface
5) Eg. Hawaii
3 reasons why people live near volcanoes
1) religious views people throw animals, money and food into the volcano which can make the local culture grow. Especially as they live with family and friends so they think it is unlikely for the volcano to erupt. Good jobs people stay- Japan
2) Minerals such as diamonds and tin, sell them for a lot of money which can lead to more money, better economic growth (Chile)
3) Ash broken down and used into fertile soil which can be used for growing crops and sold- agriculture and farming (Eg. oranges in Vesuvius)
3 reasons why people live near earthquakes
1) In Los Angeles and San Franciso- earthquake proof buildings and earthquakes are unlikely
2) Don’t have enough money to move and have many friends and family- houses are built with good foundation
3) Houses have good values and people have good jobs
How to measure the magnitude of earthquakes
Mercalli Scale:
1) Measures the impact on people- the damage
Richter Scale:
1) Measures the magnitude and strength of the earthquake
Focus
When the rock gives way
Epicenter
Is directly above the focus and it shows where the seismic waves are the strongest
Magnitude
Energy released and the strength of the earthquake
Predicting earthquakes
1)
2)
3)
Predicting volcanoes
1)
2)
3)
Building design for earthquakes
1)
2)
Building design for volcanoes
1)
2)
