Vulcanicity Content Flashcards
Name the potential hazards produced by volcanic eruptions
- Lava flows burn and bury crops
- Submarine/coastal eruptions can cause tsunami
- Ash falls ruin machinery and disrupt transport
- Ash can cause respiratory difficulties
- Lahars
- Flooding from lava and debris blocking rivers
- Pyroclastic flows
- Snow melt causing dangerous lahars
- Volcanic dust absorbs solar energy, lowering global temperatures
Name some potential benefits of volcanic eruptions
- Lava flows create new land
- Geothermal power
- Igneous rocks contain rare mineral deposits
- Volcanic sulphur is used in agricultural and pharmaceutical processes
- Igneous rocks make excellent building material e.g. Most of Aberdeen’s buildings are made from granite
- Extinct volcanoes make excellent defensive sights e.g. Edinburgh castle
- lava and ashes weather quickly into fertile soils
- Volcanoes can be great tourist attractions
What does vulcanicity refer to?
All volcanic activities related to magma being pushed into the crust
Where is volcanic activity mainly located?
Along plate margins in belts
What are the four types of boundary, process that can produce volcanoes? And give examples of these
- Spreading ridges- constructive plate margins- mid Atlantic ridge
- Subduction zones- destructive plate margins- Pacific ring of Fire
- Rift valleys- The Great African Rift Valley
- Hot spots e.g. Hawaii
How many active volcanoes are there in the world approximately?
1500
What differences are there in the lava at constructive and destructive plate margins?
Constructive- basaltic
Runny, less viscous, low in silica
Destructive- acidic (andesitic rhyolitic)
Slow flowing, viscous, high in silica
How do volcanic eruptions differ at constructive and destructive plate boundaries?
Constructive: little violence, gases easily escape
Destructive: potentially explosive, lava shatters into pieces
What are the differences in terms of material erupted at constructive and destructive margins?
Constructive: mainly lava
Destructive: lava, ash, dust
What are the differences in terms of the frequency of eruptions at constructive and destructive margins?
Constructive: regular and can be continuous
Destructive: from time to time, long dormant periods
What are the differences in terms of the form the volcano at constructive and destructive margins?
Constructive: lava plateau, shield volcano, lava only
Destructive: acid lava dome, composite cone, layers of ash and lava
Do extrusive landforms have finer or larger crystals in their resulting igneous rocks?
Finer- this is because they cool faster
Do rocks resulting from intrusive landforms have larger or finer crystals?
Larger crystals- this is because they cool slowly
Give an example of a fissure eruption
Heimay, Iceland 1973
What’s the name of the famous lava plateau in Northern Ireland on the edge of which the giants causeway is located?
The Antrim lava plateau
Where would you find fissure volcanoes?
Rifts and early constructive margins
Describe the eruptions of fissure volcanoes
Gentle and persistent
Give an example of a shield volcano
Maura loa, the largest volcano in the world
Do shield volcanoes usually have few or many vents?
Many
Where would you find shield volcanoes?
Hotspots and where oceanic meets oceanic crust
Describe the eruptions of shield volcanoes
Gentle and predictable
Give some examples of composite come volcanoes
- Mount Etna
- Mount Vesuvius
- Mount Fuji
Where would you find composite cone volcanoes?
Destructive margins
Describe the eruptions of composite cone volcanoes
explosive and unpredictable
