Volcanoes Flashcards
Characteristics shield volcanoes
They are very large because the lava is very runny and takes a while before turning solid (gentle slope)
Can be found at constructive boundaries
Characteristics Composite/strato volcano
Mix of cone and shield , eruption varies in strength made of layers ash
Unstable
They are dormant due to the time it need to build up
Form on destructive or compressional plate boundaries
How does the volcano works
The magma chamber is a large underground pool of secondary magma.
—> under pressure the magma in the chamber can rise up the main vent which is the central tube through the volcanoes
—> volcanoes typically have bowl shaped basin at the top of the volcanoes know as craters
When magma reaches the surface it is known as lava eruption from the other vents may lead to the formation of secondary
Constructive boundaries
When two continental plates move apart , leaving cracks
Allowing magma to rise up building pressure
Which then release and causing magma to erupt to the surface and cool as new land
E.g North American plate & Eurasian plate
Conservative boundaries
Two plates slide past each other on opposite direction along a fault
Become stuck causing lots of pressure
Finally release pressure the plates snap past each other, causing an earth quake
E.g North American plate and Pacific plate
Destructive boundaries
Continental plate is less dense and larger meaning the oceanic plate goes under it (subduction) . Friction causes melting of the oceanic plates and many trigger earth quakes
It may also cause magma to rise through cracks and erupt on to the surface
E.g Pacific plates and Eurasian plate
Volcanoes effects positive
Tourist attraction; income and employment
The lava and ash deposited during an eruption break down to provide valuable nutrients for the soil. This creates very fertile soil which is good for agriculture (creates fertile soil; good agriculture land to grow crop)
Geothermal heating: -> renewable resources ->heating (hot water) Tourism Minerals Fertile soil Hot springs
Volcanoes effects negative
Destruction of land property, jobs , homes transport
Many lives lost
Lava flow and Lamar can destroy settlements and clear areas of wood land or agriculture
Rebuilding cost
Unemployment
Fire breakout
Disease from poor sanitation
Gas from eruption suffocates
Pyroclastic flow
Volcanoes causes
Constructive margin- plates move away from each other; magma rises to fill the gap
Destructive margin- oceanic crust melts from friction and heat from mantle; newly formed magma is lighter so it rises to surface
Volcanoes effects on people and environment
People injured and hurt; loss of income
Water contamination
Closure of shops and increase in theft; loss of investment
Building damaged
Tsunami can follow
Accessibility difficult
Break out disease
Reconstruction costs
Volcanoes prediction
Tremors within volcano
Group temperature rises
Volcanoes swells and bulges
Emit gas and steam
Animal behavior changes
Volcanoes preparation
Set up warning systems
Create evacuation plan
Organise post-eruption plan
Emergency food supply train emergency services
Why live close to volcanoes
Mining
Tourism
Geothermal power
Friends/family
Work
Can’t afford to move
Scientists
Reduce the negative impact
Barrier walls- block and penetrates the flow of lava
Hazard mapping- map that tells where the lava goes through
—> you can tell exactly when the volcano will erupt by looking at the map
- this will provide enough time to evacuate the people from danger and death
Spraying water on the coming lava
—> spraying oncoming lava flow with seawater helps
—> citizen of Iceland poured cold water onto flowing lava down
Bomb the lava
—> if the bomb was shoot at a correct angle & correct place. The direction of the lava could divert
Volcano hazards
Ash falls- fire and ash is blasted into the atmosphere over a large area
—> blocks the sun, affecting plants
Pyroclastic flows- hot material travelling fast down slopes
—> destroys and kills the environment
Lahars- ash mixes with water and travels downstream
—> can crush and kill people
Acid rain- sulphur dioxide and hydrogen sulphide is released
—> damage buildings and ruins rock structures
