Restless earth Flashcards
7 Major tectonic plates?
- Pacific
- Porth American
- South American
- Eurasian
- Antartic
- African
- Indo-austrailian
Describe the earth structure.
Inner core, Outer core, Mantle, Crust
Two kinds of crust?
Oceanic crust- thinner and more dense
Continental crust- thicker and less dense
Describe destructive plate margins (5).
- An oceanic and continental plate collide.
- The oceanic plate is denser than the continental plate so therefore it sinks underneath the continental plate - this is called subduction.
- As the oceanic crust sinks down into the mantle it melts- forming magma.
- As energy builds up the magma may force its way through the continental crust and explode as a volcano.
- Friction may cause an earthquake.
Describe constructive margins.
Two plates are moving away from each other. magma rises and fills the gap, cools and creates new crust.
Conservative plate margins?
Two plates are moving past each other or moving in the same direction at different speeds. when they stick, pressure builds up and can be released as an earthquake. crust is not created or destroyed.
What are fold mountains and how are they formed?
Mountains formed when plates collide at destructive margins. Sedimentary rocks build up and form high, rocky mountains with step slopes, often with snow and glaciers and lakes.
What 5 things do people use the alps for?
- Farming- goats and vineyards
- Hydro-electric power- Switzerland gets 60% of its power from this.
- Tourism is a large part of the economy.
- Mining, salt, iron, gold. declined due to cheaper foreign sources
- Forestry - Scot’s pine. trees used for furniture.
Describe tourism in the Alps.
100 million tourists
Skiing, snowboarding in winter
Walking climbing in summer
Villages, like Tignes in France, have been built for the quantity
Ski runs, restaurants, chalets, and cable cars have also been built.
How have people adapted to life in the Alps? (3)
- Steep relief. goats are farmed because they are good with mountains. avalanches and rock slides ain’t an issue because of trees and man-made defences.
- Poor soils? No problem, graze animals there instead of plants.
- Limited Communications - Roads built over lower parts of the mountains can get blocked with snow, so tunnels have been built to provide fast transport links
Where are volcanoes usually found?
Destructive and constructive plate margins.
How are volcanoes formed at destructive plate margins? (4)
- Oceanic plate (more dense) goes underneath the continental plate, into the mantle where it is melted.
- This forms a pool of magma.
- This magma rises through vents in the crust.
- The magma erupts, forming a volcano
How are volcanoes formed at constructive plate margins?
- Magma rises into the gap as the plates move apart, forming a volcano.
How do scientists try to predict volcanic eruptions in advance?
By monitoring signs of an incoming eruption, like…
- tiny earthquakes
- escaping gas
- bulges or shapes in the volcano
What volcano erupted in Montserrat in 1997?
Soufriére Hills volcano
