The Basics About Volcanoes Flashcards
What is a volcano?
A volcano is an opening in the Earth’s crust through molten rock and gases erupt from deep below.
What is the crater?
It is the basin shaped depression in the top of the volcano.
Where material and gas is ejected from.
What are volcanic bombs?
They are semi-molten pieces of rock that erupt from the vent of the volcano.
They vary in size from golf ball to car size.
What are secondary vents?
Sometimes there is great pressure inside the volcano and the crater is blocked.
Magma is forced to the surface by a different route.
Where is exits the volcano, it produces a secondary vent.
What is the magma chamber?
Where all the molten rock that comes out the volcano is stored underground.
When pressure builds up the magma rises to the surface and comes out the crater as lava.
What is the main vent?
The long shaft that feeds magma from the magma chamber to the crater at the opening of the volcano.
Where is the crater located?
Top of the volcano in the middle.
Where is the main vent located?
Up the middle of the volcano.
How do volcanoes form?
When magma escapes through a vent which is a fault or crack in the Earth’s crust.
Where do volcano’s also occur?
Constructive plate boundaries
Name well known volcanoes made from many eruptions of magma.
Mt St Helens.
Etna.
Vesuvius.
Pinatubo.
What happens each time an eruption takes place?
A new layer of lava is added to the volcano.
Building it up and creating familiar cone shape.
What other products may be thrown out of a volcano?
Gas. Cinders. Volcanic bombs. Pumice. Dust. Ash. Steam.
