Volcanoes Flashcards
Types of volcano
Shield, composite, super
Describe shield volcano formation, description, plates and example
Formation: low viscosity lava flows down (flows easily) this gives it the shallow sloping sides
Description: wide volcano, shallowly sloping sides
Found on constructive plate boundaries
E.g. Mauna Loa, Hawaii
Describe composite volcano formation, description, plates and give example
Formation: formed when different types of eruptions deposit different materials around sides. It has layers lf hardened ash and tephra. Lava cools and hardens before spreading far (high viscosity)
Description: coneshape volcano
Found on destructive plate boundaries
E.g. Mount St. Helens in Washington state
Supervolcano description formation etc
Description: a volcano on a massive scale which has had an eruption of VEI (volcanic explosivoty index) 8 and has to erupt at least 1000km3 of material
Formation: there is a magma chamber in the mantle. The magma starts to rise due to pressure and forms a bulge. Pipelines are formed which lead to earth’s surface. Eventually, pressure becomes too much and it explodes. As magma chamber is left empty, the ground/crust falls into the hole cresting a caldera.
E.g. Yellowstone
Volcano vocab
Liquid which flows out: lava
Place where lava flows out: vent
Place where lava is stored: magma chamber
Tube that gets lava from chamber to vent: conduit
Cloud of ash: ash cloud
Place where lava flows to the side: side vent
Four reasons people want to live near volcanoes
Minerals, tourism, fertile soils, geothermal energy
Explain minerals
Attractive to people because they are ideal, for large scale mining businesses and smaller scale local activities by individuals and small groups. Sell minerals to make money
Explain tourism
Earn money —> helps economy
More jobs
Explain fertile soils
Perfect for growing crops, so people can make money from selling them —> helps local economy
Explain geothermal energy
Can be used to produce electricity or to heat water supplies which provide household heating and hot water
Two types of hazards
Primary: caused by specific volcanic activity, such as ongoing eruptions
Secondary: occur as result of eruption, often because of instability of volcano
Two primary hazards
Pyroclastic flow: huge, fast moving clouds of hot rock fragments, lava particles, ash and hot gases. Can be 1000°C and move up to 430kph
Volcanic gases: volcanoes emit gases which can harm people and cause death. Gases such as carbon dioxide and sulfur dioxide can also cause global warming and acid rain
Two secondsry hazards
Lahars: mudflows of volcanic ash and debris mixing with water (on steep slopes can reach 22metres/second
Volcanic landslides: slides of rock and loose volcanic material which triggered by the movement of an eruption and slide downhill under gravity
Iceland volcano
Facts: strato volcano on spreading ridge in Iceland, Mid-Atlantic Ridge, ash reached 11000m in air
Causes: As ice started to melt, glacial water began flooding into volcano where it met the magma. The rapid cooling caused magma to shear into fine jagged ash particles
Social impacts: 500 fsrmers and their families evacuated, roads were shut down, ash contaminated water supplies
Env impacts: animals evacuated and could not drink water, a lot of CO2 emitted 30 000 tonnes, scientists feared climatic impact
Economic impacts: flights cancelled which meant jobs put on hold, lost £130 million a day, crops could not be flown or sold
Response: countries affected by hazard responded by themselves or colllectively and had capacity to do so. Tried to fly planes by using tests.
