Hazards - Volcanic Flashcards
What lava is formed at destructive plate margins and what are its features? (4)
1 - Andesitic + Rhyolitic
a) Cooler
b) Viscous - flow slower
c) Eruptions are intermitent and short yet violent
What lava is formed at Constructive margins and what are its features? (4)
1 - Balsatic lava:
a) - Very hot
b) - Low viscosity (runny) - Flows quickly
c) - Eruptions of this lava are frequent and enduring but not explosive
How does Andesitic and Rhyolitic lava erupt? (3)
1 - At subduction zones, melting of the subducted plate forms magma which rises to the surface as volcanoes.
2 - The lavas are viscous and forms blockages in volcanic vents causing a build up of pressure
3 - The blockage is cleared by a violent eruption
How does Basaltic Lava erupt?
If margin on land, as plates pull apart they become thinner and magma breaks through the service
What is a pyroclastic flow and what is its effect? (3)
1 - Mixture of hot gas, ash and volacanic rock that flows down a volcanoe
2 - Causes widespread death and destruction as give little warning and travel fast and far
3 - Melt snow cause flooding
What are the effects of lava flows? (2)
1 - Most flows are slow so people have time to evacuate
2 - But destroy anything in its path
What are Volacanic gases and there effects? (3)
1 - Lava contains CO2 and sulfer dixoide which are released into atmosphere duirng eruption
2 - Harmful if breathed in
3 - Contribute to the enhanced greenhouse effect
What are Lahars and what are there effects? (3)
1 - Mudflows caused by volcanic material mixing with water
2 - Quick and travel far
3 - Can bury the environment
What is Acid rain and what are there effects? (3)
1 - Volcanic gases react with water to produce acid rain
2 - Can cause acidififiaction of aquatic ecosytems, killing some marine life
3 - Removes nutrients from the soil, damaging carbon cycle in forests
What is pyroclastic fallout?
Material that has been ejected from a volcanoe
What is the effect of fallout? (3)
1 - Large tephra can damage infastructure and kill people
2 - Harmful if breathed in
3 - Reduce the amount of sunlight hitting earth, decreasing temp over large areas
what is ash fallout?
Fallout consisting mainly of ash
How can the magnitude of eruptions be measured and what does this measure? (3)
1 - Volcanic Explosivity Index (0-8)
a) How much material ejected
b) How high the material is blasted
What type of volcanoes can Balsatic lava form and why?
1) Flows quickly so forms volcanoes with gentle slopes, shield volcanoes
What are the social impacts of volacanic hazards? (3)
1 - Kill people
2 - Mudflows and flooding from ice melts can further increase death toll
3 - Lava flows can start fires which can damage buildings - homelessness
What are the eonomic effects of volacnic hazards? (4)
1 - Ash clouds can prevent aircraft flying
2 - Ash clouds can damage crops
3 - Destroy businesses
4 - Eruptions can create curiosity and attract tourism
What are the political effects of volcanic hazards? (2)
1 - Damage to crops can cause food shortages leading to conflict and political unrest
2 - Gov has to fund for repairing damage rather than hospitals and schools - stunt development
How can the risks of volacnic hazards be prevented?
Prevent land being developed near volcanoes
How can the risks of volcanic eruptions be prepared agaist? (4)
1 - Install monitoring systems to give time for evacuation
2 - Stop people from enetering high risk areas
3 - Individuals can plan: finding out where the nearest shelter is, making an emergency kit
4 - Communities can set up search and resuce teams
How can people adapt to minimise the risks of volcanic hazards? (2)
1 - Strenghten buildings to prevent it collapsing under weight of ash fallout
2 - People can capatilse on the opportunities of living near a volcanoe:
- Farming - ash makes fertile soil
- Working in tourist industry
How can people adapt to minimise the effects of volcanic hazards? (2)
1 - Strenghten buildings to prevent it collapsing under weight of ash fallout
2 - People can capatilse on the opportunities of living near a volcanoe:
- Farming - ash makes fertile soil
- Working in tourist industry
