Volcanic Hazards Flashcards
(23 cards)
Tephra
Material ejected from a volcano
Can be fine ash or large rocks
Examples of a volcano with tephra involved within the eruption
2010 Eyjafjallajokul
How hazardous is tephra
Very hazardous
Covers agricultural land and destroys crops
Causes air space to close
What is ash fallout
Volcanic ash is ejected from the volcano
This creates an eruption column
This can travel long distances
Example of ash fallout
2010 ejyafjallajokul
How hazardous is ash fallout
Hazardous
Covers surfaces including buildings, roads and farms over thousands of km
Weight of ash can collapse buildings
How far can eruption columns be transported into the atmosphere
45km
Volcanic gases
Release wide range of toxic gases
Eg. CO, CO2, SO2
Example of volcanic gases - case study
1986 underwater volcano eruption
Lake Nios North Cameroon
1200 killed , 300 hospitalised
How hazardous are volcanic gases?
Silent and deadly threat to humans
Cause irritation to eyes, nose, throat
Mix with water to form acid rain
Mudflows / lahars
Form when deposits of ash, rock and water combine together
Example of mudflow / Lahar
November 13th 1985 Armero Tolima
25,000 deaths
Buried town of Armero
Known as Armero tragedy
How hazardous are mudflows
Very hazardous
Ability to consume everything in their paths
Either destroyed or buried under debris
Nueés ardentes
Similar to pyroclastic flow
Denser / slower
How hazardous are Nuées ardentes
Very hazardous
Contain poisonous gas and hot ash
Pyroclastic flow
Fast moving current of hot gas and rock which travels downhill due to gravity
Travels up to 700 km/h
Reach temperatures of 1000 degrees
How hazardous are pyroclastic flows
The inhalation of poisonous gas and hot ash can cause instant death
Destroys anything in their path
Lava flow
Flow of lava down the sides of the volcano
Can be viscous or runny
Travel speeds up to 40 km/h
1000-2000 degrees
How hazardous are lava flows
Depends on the speed
Can be out run
Lava flow example
2014 Fogo volcano eruption Cape Verde
Fast moving lava flow engulfed 75% of buildings within 3 villages
Acid rain
When sulphur dioxide from the volcano combines with water vapour to form acid rain
How hazardous is acid rain
Pollutes surface
Enhances weathering
Damages crops
Acid rain example
Tonga 2022
Volcano has been releasing toxic gases
