Volcanoes Flashcards
What is a volcano? Name their 3 types.
A volcano is a cone shaped hill or mountain formed by magma from the mantle being forced through an opening or vent in the Earth’s crust.
Define active, dormant and extinct volcanoes.
Active volcano - a volcano that is erupting or which has recently erupted
Dormant volcano - a volcano that has not erupted in a long time but which is known to be capable of erupting
Extinct volcano - a volcano that scientist believe will never erupt again
Explain the process of a volcanic eruption.
In the mantle, due to heat from the core, magma heat up. The convection currents cause the lighter and dense magma to rise and sink. The melted magma can accumulate when it reaches the crust, in the magma chamber. Over time, the surrounding rock cracks under the build u of pressure. When this happens, in order to release the pressure, the magma wll make its way up through the cracks, towards the Earth’s surface. Once the magma reaches the surface of the Earth, it moves through the opening, known as the vent, and is now known as lava.
Name the positive effects of volcanoes.
- Volcanic materials produce fertile soils
- Volcanoes are also important tourist attractions
- Geothermal energy is where heat from within the Earth is used to generate electricity.
Name the negative effects of volcanoes.
- large volcanic eruptions can cause death and the destruction of property
- Air traffic can be disrupted
- Volcanic eruptions can release toxic chemicals such as sulphur dioxide and carbon dioxide
- If there are glaciers next to volcanoes, they can melt and cause floods
- Agricultural land can be destroyed by ash following a volcanic eruption
How are volcanoes made in destructive plate margins or constructive plate boundaries?
Volcanoes made in destructive plate margins are mainly on land, called composite volcanoes. These are more destructive.
Volcanoes made in constructive plate margins are mainly underwater, called fissure volcanoes. Fissure volcanoes create new land and are not as destructive.
What is a magma chamber?
A magma chamber is a reservoir of magma (molten rocks) located deep inside a volcano.
What is a crater?
A crater is a wall shaped opening at the top of a volcano.
What is a vent?
A vent is a channel through the volcano, which allows magma within the volcano to reach the surface.
What is a secondary cone?
A secondary cone is an alternative route that magma may take to reach the surface if the crater is blocked.
How does a volcano grow?
The layers of lava and ash build up with each eruption, and the volcano grows in size.
What is the lava flow?
The lava flow is the name for magma (molten rock) once it has reached the surface.
What is an eruption cloud?
An eruption cloud is a mixture of ash, gas, rocks, and steam.
