Structure of the Earth
The Earth is made up of three main layers. These are the crust, the mantle and the core. The crust is the thinnest layer of the Earth, and is made of cool, solid rock. Beneath the crust is the Earth's mantle, which is made up of constantly flowing molten rock. As you go deeper beneath the Earth's surface, the pressure of the layers and the temperature of the Earth's core creates lots of heat. This heat melts the rock in the mantle. The Earth's core is super-pressurised and super-heated.
Conservative - two plates move in the same direction. One moves faster than the other and this causes pressure to build between the two plates until one jolts past the other, releasing it. This causes earthquakes. It can also cause the land to diverge and become ridged.
Constructive - two plates diverge. This causes volcanoes to form as lava rises through the gap in the crust.
Destructive - an oceanic plate and a continental plate converge. As the oceanic plate is denser than the continental plate it is submerged. Friction causes melting of the oceanic plate and may cause earthquakes. Magma may rise through cracks and erupts onto the surface.
Collision - two continental plates collide. Neither is forced under the other so they are both pushed up to form fold mountains.
Fold mountains are formed on a geosyncline (a large-scale depression in the Earth's crust). Different layers of sediment gather into the geosyncline and over time sediment will build up. When the tectonic plates on the geosyncline converge and push up, the sediments are forced up. This makes the layers uneven and ridged. After millions of years, these sediments harden into fossilised rock, forming fold mountains.
A volcano is an opening in the Earth's crust which allows hot magma, ash and gases to escape from below the surface.
- Gently sloping sides (formed by basic lava which is not very viscous)
- Layers of lava
- Runny lava
- Gentler eruptions
- Formed at construcive plate boundaries
- Steep sides (formed by viscous lava)
- Viscous lava
- Layers of lava and ash
- Violent eruptions
- Formed at destructive plate boundaries
The Alps is a fold mountain bordering Italy, France, Switzerland, Austria and Slovenia.
- Relief - mainly high and steep. Little flat land for farming/building settlements
- Climate - Colder, windier, wetter and snowier at higher levels; crops can't be grown
- Soils - typically stony, thin and infertile
- Accessibility - Roads and railways = expensive; rock falls & avalanches disrupt transport.
Human activities -
- Farming - located on south-facing slopes. Transhumance is seasonal movement of animals. Cable cars used to transport products. Farmers buy in feedstuffs for cattle.
- Tourism - winter = skiing; hotels; restaurants; ski lifts. Summer = lakes; mountains
- HEP - steep slopes, high precipitation & thawing glaciers produce fast-flowing rivers. Narrow valleys are easy to dam. Some of electricity is exported to other regions, to towns and cities.