GEO 3.2 EARTHQUAKE AND VOLCANO Flashcards
volcano
An opening in the Earth’s crust through which hot molten magma (lava), molten rock and ash are erupted onto the land.
Where are most volcanoes usually found?
Plate boundaries
although there are some exceptions, or a hotspot.
What are the two main types of volcanoes?
- Strato-volcanoes (composite cone)
- Shield volcano
Name the features of ‘strato-volcanoes’ + one example.
- Narrow and steep
- Explosive
- Destructive
- Silica lava
- Only have one or a few vents to release lava
- When the lava cools, these layers of lava become the sides
e. g. Mount St Helens
Name the features of ‘shield volcanoes’ + one example.
- Wide and gentle slopes
- Non-violent
- Constructive
- Basaltic
- Occur at hot spots under the Earth’s surface
- Erupt frequently, with lava spilling out from many vents
e. g. Mauna Loa
Stratovolcano or composite cone.
A volcano made from alternate layers of lava and ash.
Shield volcano
A large volcano with gentle sides, built up by non-viscous lava and very little ash.
Crater
The depression at the top of a volcano.
Dormant volcano
A volcano which has not erupted for some time, but which might erupt again in the future.
Extinct volcano
A volcano that will never erupt again.
Lava .
Molten rock ON the Earth’s surface.
magma
Molten rock BELOW the Earth’s surface.
What comes out of a volcano?
- Gases
- Liquids (lava)
- Solids (Pyroclastic material) = ash and other particles
advantages brought by volcanoes
- geothermal power
- fertile soils
- creations of new landmass
- tourism
- mineral and mining
Tsunami
An ocean wave produced when there is movement of the seabed caused by the fault movement that causes an earthquake. A tsunami can also be caused by the collapse of a volcanic cone into the sea.
