Volcanoes Flashcards
What is a volcano?
A volcano is an opening in the Earths surface. It is a tectonic land form created by tectonic plates. Many volcanoes occur at plate boundaries.
What is a volcanic eruption?
A volcanic eruption is the release of heat, lava, ash and gas through the earths crust. These are different types of eruptions not all with lots of lava.
What happens when magma reaches the surface?
When magma reaches the surface it is called lava and when it cools it forms rock
What boundaries can volcanic eruptions happen at?
Volcanic eruptions can happen at destructive and constructive boundaries but not at conservative boundaries.
Where can some volcanoes be found?
Some volcanoes are underwater on the sea bed or ocean floor
Active
Erupted recently likely to erupt again
Dormant
Hasn’t erupted for 2000 years could erupt again
Extinct
Highly unlikely to ever erupt again
What happens when lava cools?
Lava cools and gardens to form an igneous rock. The most common one is basalt. Glassy lava that explodes out forms pumice.
What consistency is magma?
Magma can be viscous (thick like tar) or as runny as thin custard. It depends on the rock that melted.
What is volcanic gas made up of?
Volcanic gas is mainly steam and carbon dioxide, plus some sulphur dioxide and other gases. It smells of rotten eggs and it can suffocate you.
Volcanic eruption:
- Red hot lava may flow down the side of the volcanoes through the secondary vent.
- If the lava is thick and gassy it can’t run out of the volcano easily the pressure builds up until it explodes.
- As it explodes it cools and hardens giving a cloud of particles of all sizes from dust and ash to big lumps mixed with scorching gas.
- The heavy cloud will collapse and rush down as a deadly pyroclastic flow.
- If this gets mixed with water (e.g. a river or melting snow) you get a river of mud called a mudflow.
Shield volcanoes
- Often at constructive plate margins
- Wide base
- Gently sloping sides
- Eruptions can be violent
- Lava is runny so can flow a long way
- Basic lava (opposite of acidic)
Composite Volcano
- Often at destructive plate margins
- Steep sided
- Steam, ash, lava and rock also ejected
- Made up of alternate layers of ash and lava
- Can be violent
- Sticky (viscous), ‘acidic’ lava which.can’t flow far
Give two volcanoes in Europe?
Mount Vesuvius and Mount Etna
Give a volcanoes from outside of Europe?
Yellowstone
Where is Eyjafjallajokull located?
The South West of Iceland
The North Atlantic Ridge
Why does Iceland experience volcanic eruptions.
The North American and Eurasian plate are pulling apart to magma wells up from underwater volcanoes. Over 70 million years the volcanoes have grown into a mountain ridge it’s called the mid Atlantic ridge. Most of the ridge is underwater but it sticks up into a few places forming Iceland. This is where it sticks out and forms Iceland. Iceland grew taller than the other parts of the ridge because extra magma spurts out fed by a current of magma called a plume. The plume is still there and the plates are still moving apart.
Facts about Eyjafjallajokull
It is one of the least active volcanoes in Europe
In April 2010 the volcano became headline news as it erupted and had impacts that were felt across Europe
The eruption happened underneath an ice sheet
Dissolved gases in the molten rock along with the steam generated from the melting ice caused a large column of volcanic ash.
What were the effects of the eruption in Iceland?
A 500m fissure opened up
Areas were flooded because of the glacier melt which lay above the volcano
Agriculture land was damaged and farms were damaged and farms were hit by heavy ash fall
The ash fall poisoned animals in nearby farms
Some roads were destroyed
People were asked to stay indoors because of the ash in the air
20 farming families were evacuated
The effects of the Eyjafjallajokull eruption in Europe
Flights had to be cancelled because of the ash cloud. It caused turmoil in the air for almost a month.
What is the main volcano in North America
Yellowstone
The social impacts of a Yellowstone eruption
SOCIAL IMPACTS 1 in 3 people affected will die All life up to 1000 km will die Peoples housing will be destroyed Due to crops getting destroyed people will starve Up to 5 billion people will be killed
The economical impacts of a Yellowstone eruption
ECONOMICAL ERUPTION
The ash would affect transport, electricity, businesses, water will be polluted, crops will fail
The economy will collapse
It would effect key transport
Businesses because of low customers and damage
Decrease in tourism
The environmental impacts of a Yellowstone eruption
ENVIROMENTAL IMPACTS
Likely to destroy 10,000km squared of land
The ash thrown up in the air would reduce the level of radiation from the sun causing freezing cold volcanic winters across the planet
Earth quakes
Ash cloud would cause climate change
