Characteristics of a composite volcano
- Made from andesite lava
- Steep sided
- Highly explosive
Characteristics of a shield volcano
- Made from basalt
- Low, wide cone
- Non-viscous lava
- Non-explosive
Liquefaction
When land acts like liquid due to seismic shaking
The bay area of Kobe
Osaka Bay
Caldera
A deep depression created by a super volcanic eruption
Characteristic of an oceanic plate
- Newer (less than 200 million years old)
- Denser
- Can be sub ducted
- Can be renewed or destroyed
Characteristics of an continental plate
- Older (more than 1500 million years old)
- Less dense
- Cannot be sub ducted
- Cannot be renewed or destroyed
Destructive subduction plate margin
Due to convection currents, the oceanic plate sub ducts beneath the continental. The oceanic plate melts and the crust becomes magma. As the crust melts gasses are released. Pressure builds, leading to an eruption. Layers of magma and ash create the shape of the volcano.
Conservative plate margin
The plates brush against each other
-pressure builds causing the plates to jolt into a new position
Constructive plate margin
Oceanic plates are forced apart by convection currents
Geosyncline
Natural dip found of the ocean bed
How are fold mountains formed?
- Geosyncline
- Ocean deposits sediments in these geosynclines
- Sediments are compressed and are turned into sedimentary rocks such as limestone
- Plates are forced together at destructive plate margins (can be subduction or collision)
Sediment layers are forced upwards into fold mountains.
How are ocean trenches formed?
Ocean trenches are formed when two plates collide at a destructive subduction plate margin . The oceanic plate is dragging down the continental, creating the ocean trench.
How do people use fold mountains?
- Tourism
- main source of income
- summer activities such as mountain biking and climbing
- winter activities such as skiing - Farming
- transhumance (seasonal farming) - Mining
- easy mining of metals and minerals - Hydroelectric power
- steep V shaped valleys, easy to dam
Case study for fold mountains
Livigno, Italy
- Invested heavily in the ski industry
- Skiing forms over 90% of Livigno’s economy
1. Developed alp lines infrastructure to overcome limited communication: - Swiss built road and tunnel network linking Livigno into the outside world
- Roads are built with snow sheds to ensure year round access to towns.
- Cable cars and 33 ski lifts added to improve access to 115km of ski slopes.
Earthquake
The violent shaking of the ground
Focus
Where the pressure is released along the fault line
Epicentre
Located directly above the focus on the earth’s surface. This is where the most energy is felt
