Volcanic Hazards Flashcards
(6 cards)
Pyroclastic Flow
Mix of hot rock, lava, ash and gases
More common with andesitic lava
Often occur at subduction zones
Move at around 200m/s
Can travel large distances
Temperatures of 350oC - 1000oC
Nuee Ardente
Means ‘glowing cloud’
Contain more dense material
Are normally only found 50km from source
Tephra
Rock fragments ejected during an eruption
Large fragments land close to the source
Small fragment (ash) can travel great distances
Ash can cause breathing difficulties, block sunlight and alter temperatures
Lahar
Ash and volcanic material mix with water
Commonly occurs in glaciated areas due to the rapid melting of the ice
Flows at speeds upto 60km/h
Can be highly erosive
Will engulf anything they pass over
Lava Flows
Lava flows down the side of a volcano
Low viscosity lava travels at 10km/h and may cover hundreds of kilometers
Slow flow rate allows for evacuation
Will destroy anything it passes over
Gases & Acid Rain
Co2 and SO2 are released upon eruption
Can cause breathing difficulties and harm wildlife
Gases react with water vapour creating acid rain
Damages ecosystems and infrastructure