PMT - volcanic hazards (the hazards associated with volcanoes)

Question 1

what are the main 6 volcanic hazards?

Answer 1

lava flows
lahars
tephra
toxic gases
acid rain
pyroclastic flows

Question 2

what can determine the lava flow speed?

Answer 2

its viscosity

if there is a higher silica the lava is more viscous so its slower

Question 3

what makes lava more viscous and slow?

Answer 3

silica

Question 4

what is a lahar?

Answer 4

volcanic mudflows made up of volcanic debris and hot or cold water

Question 5

what is tephra?

Answer 5

any type of rock ejected by the volcano

Question 6

what is acid rain caused by?

Answer 6

when sulphur dioxide is released into the atmosphere mixing with precipitation

Question 7

what is a pyroclastic flow/nuees ardente?

Answer 7

clouds of burning hot ash and gas that collapses down a volcano at high speeds

Question 8

what is the average speed of a pyroclastic flow?

Answer 8

60mph but can reach up to 430mph

Question 9

what is a volcano?

Answer 9

an opening in the earths crust through which magma/lava, ash, gases erupt

Question 10

molten rock is igneous in origin but if it reaches the surface/or injected into the crust what is it described as? what are the two made from?

Answer 10

reaches the surface = extrusive = made from lava

injected into crust = intrusive = made from magma

Question 11

how many active volcanos does indonesia have?

Answer 11

76

Question 12

what is the worst recorded lahar event in history?

Answer 12

1985
23,000 died
Nevado del Ruiz volcano
Colombia