Earthquakes And Volcanos Flashcards
What is an earthquake
Earthquake is the shaking of the earth
Earthquakes happen so suddenly because seismic waves, they pass through the Earth in all direction, shaking everything
Earth resulting from a sudden release of energy in the Earth’s lithosphere that creates seismic waves
Seismometer
Measures earthquakes
Crater
Opening at the top of the volcano
Magma chamber
Store of hot, molten rock beneath
Layers of ash and lava
Build up overtime to form the sides of the volcano
Main vent
The tunnel in which magma rises to the top iof the volcano
Secondary vent and cone
Allows magma to escape from the side of the volcano
Lava flow
Molten rock flowing down the side of the volcano
Volcanic cloud
Gas, steam and ash escaping from the volcano
Volcanic bombs
Large pieces of rock ejected from the volcano
Composite volcano
Are found at destructive plate boundaries.
They have very violent eruptions, which force volcanic bombs out of the vent.
Lahars (mudflows) can happen when rainwater mixes with ash
The lava running down the volcano is thick like treacle.
The lava escapes through an number of vents and parasitic cones
This viscous lava moves more slowly.
Composite volcanoes have a narrow base due to the slow moving lava. It cools and sets before it travels far.
There are also steep sides.
The volcano is made up of layers of ash and lava
Mount St. Helens in the USA is a composite volcano
Shield volcano
Shield volcanoes have are only made of lava.
Because the lava travels far before it sets the base of the volcano is very wide and the slopes very gentle.
Shield volcanoes have thin runny lava which moves quickly.
This lava runs down hill quickly and spreads over a long distance before it cools.
The lava escapes through one large vent which means lots of lava reaches the surface
Are found at constructive plate boundaries.
They have very gentle eruptions, and no volcanic bombs
Mauna Loa in Hawaii is a shield volcano
Why do people live near a volcano?
Crop growth and sale, tourism people mine minerals gives them well-paid job
What happens at the formation of a volcano at a destructive plate boundary?
At a destructive plate Boundry one goes underneath the other. The plate that subducts goes into the mantle, the subduction zone, plate melt, magma goes up
Icelandic volcano
March 20 2010 the volcano began erupting under a Glacier, producing ash in the sky. Constructive plate boundary and they moved apart.
The ash cloud reached 55000 feet
Its 1666 metres tall
The crater of the volcano measures 1.8 miles to 2.5 miles across