Volcanoes Flashcards
On which plate boundaries are volcanoes found?
Constructive e.g Iceland
Destructive subduction e.g. chile
What is tephra?
rock fragments and particles ejected by a volcanic eruption.
What is a pyroclastic flow?
A pyroclastic flow is a fast-moving current of hot gas and volcanic matter that moves away from a volcano about 100 km/h on average but is capable of reaching speeds up to 700km/h
What is a lahar?
A lahar is a violent type of mudflow or debris flow composed of a slurry of pyroclastic material, rocky debris and water. The material flows down from a volcano, typically along a river valley.
Which type of volcano has gently sloping sides?
Shield volcano
Which type of volcano has steep sides and layers of lava and ash?
Composite volcano
Which type of volcano ejects viscous (thick and sticky) lava?
Composite
Which type of volcano ejects runny lava?
Shield volcano
Which type of volcano is generally more hazardous - composite or shield volcano?
Composite - violent eruptions (Plinian)
What is the difference between magma and lava?
Magma is in the mantle, lava is what comes out of the volcano on the surface of the earth.
Where is magma stored under the volcano?
The magma chamber
Give 4 reasons why people live near volcanoes.
- Geothermal energy e.g. Iceland and Kenya
- Tourism e.g. Iceland, Vesuvius in Italy
- Fertile souls e.g. grapes grown on the slopes of Vesuvius in Italy
- Lack of perception of the threat
- Can’t afford to move
- Mining for minerals
What is an active volcano?
An erupting volcano or one likely to/capable of erupting any time/in the near future.
What is a dormant volcano?
A volcano that is not erupting or predicted to erupt in the near future. However, it has done so in recordable history.
What is an extinct volcano?
A volcano that has not had an eruption for at least 10,000 years and is not expected to erupt again.
