Volcanic Hazards Flashcards
Lists me 6 volcanic hazards
- lava
- gases
- pyroclastic & ash fallout
- pyroclastic flows
- lahars
- tephra
What is lava?
Magma above the surface
What is magma?
Molten rock
Give 3 facts about lava
- speed of a lava flow depends on the materials making up the lava
- thick lava flows are at risk of collapsing, which can cause pyroclastic flows
- in the 2018 Kilauea volcanic eruption, lava flows destroyed homes and cars
Give 2 types of lava flows
- Basalt flows are runnier and move faster
- andesite flows are thicker (more viscous) and move slower
Basalt flows SiO2 percentage
50%
Andesite flows SiO2 percentage
70%
What gases does a volcano eruptions contain (2 things)
Sulphur dioxide and carbon dioxide
What can sulphur dioxide do?
Cause acid rain
What is a pyroclastic fallout?
Any material that has been ejected from the volcano and has travelled through the aid or atmosphere and fallen to earth
What is ash?
Tiny pieces of burnt rock fragments that are blown into the atmosphere, usually at some force
Example of an ash fallout
2010: ash from Eyjafjallajokull eruption in Iceland caused flights to be grounded because of the risk of damage to the plane engines
What’s another word for pyroclastic flows?
Nuées ardentes
What is a pyroclastic flow?
- Currents of hot ash, lava and gas that can move downhill at speeds of up to 500km/h during an eruption
- reach temps up to 1000 degrees and can cover distances to 30km
What is a lahar?
If volcanic ash or lava mix with water, lahars (mudflows) may form
Where can a lahar also happen?
When a volcano has a glacier
What is tephra?
Rock fragments that are ejected from the eruption
How far can tephra travel up to?
80km