Volcanic Hazards

Question 1

Pyroclastic Flow

Answer 1

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

Question 2

Nuee Ardente

Answer 2

Means ‘glowing cloud’

Contain more dense material

Are normally only found 50km from source

Question 3

Tephra

Answer 3

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

Question 4

Lahar

Answer 4

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

Question 5

Lava Flows

Answer 5

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

Question 6

Gases & Acid Rain

Answer 6

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