Volcanoes Flashcards
Divergent plate boundary
Where tectonic plates are pulled apart allowing molten rock to emerge at the earths surface
Vent
Opening in a volcano through which molten, rock and gas can escape
Ring of fire
Volcanoes which have formed around the Pacific Ocean
Hotspot
An area where mantle has melted resulting in rising magma
Magma
Hot fluid or semi fluid material below or within the earths crust
Pyroclastic flow
Mixture of rock, ash, gases and water that moves rapidly down slope
Caldera
Large, basin shaped depression
Pangaea
Wegners parent landmass( supercontinent )
Lava dome
A mound of viscous lava
Seafloor spreading
The separation of tectonic plates on the floor of the ocean
Plate tectonic theory
The idea that earths outer shell is divided into several plates. They slide over one another
Transform plate boundaries
Where plates slide past each other. Hey are often found on the sea floor
Volcanology
The study of volcanoes and the associated geomorphic processes
Lithosphere
One of the earths four spheres. Consists of the crust and mantle( rocks, Mountains ect. )
Phreatic eruption
Steam driven explosions. Occur when ash and steam are forced out of the vents
What is the difference between lava and magma
Magma is composed of molten rock and is stored in the earths crust. Lava is magma that reacher the surface of our planet grouch a vent
How is a dormant volcano different to an extinct volcano
A dormant volcano is active, it is not erupting but is likely to. Extinct volcanoes have not erupt in 10000 years and is not likely to
Why do earthquakes occur and why some areas are more prone to earthquakes than other
They occur because of the plates colliding, and some are more prone because they are closer to plate boundaries
If active volcanoes can be dangerous why do people live and work on their slopes
People still choose to stay there because of the advantages like minerals and fertile soil, geothermal energy and tourism. People believe that volcanoes are predictable, so they will know if it is going to erupt
Give two examples of how volcanic eruptions can cause damage to the surrounding environment
Many gases are emitted that are harmful, sulphur dioxide is converted to sulphuric acid in the stratosphere, this is the main cause of acid rain. CO2 is a green house gas that leads to global warming
Describe the social impact in Montserrat from the volcanic eruption
Decreasing population and infrastructure. In Plymouth 1995 it was home to about 4500 people- a third of the islands population. It also housed the main port, all the government buildings and most of the businesses. Now it is buried by debris and lava from the volcano above it. When the evacuation began prisoners were housed in a community center, the treasury and radio stations were run out of people’s homes. Many peoples homes became part of the exclusion zone and so they lost many possessions and could never live in their home again
Describe the economic impact in Montserrat
Many businesses closed down or were destroyed. Lots of people were living in the shelters and schooling was done in a church. Work was so unavailable many people chose to leave the island. Because of the fertile soil on the slopes of the volcano there were many farms that were completely destroyed by the pyroclastic flow
Describe the environmental impact in Montserrat
Ash in the water is damaging to the chicken frogs skin. Many habitats were wiped out by pyroclastic flow. The volcano releases gases that poison the plants and cause acid rain. The pyroclastic flow reached far enough to the damage a popular reef. The spot used to be popular with divers but it is expected never to recover
