volcanoes- the hazards and effects

Question 1

What hazard is Lava flow and how is its speed determined

Answer 1

Primary hazard determined by the viscosity of lava and the amount of silicon dioxide it contains

Question 2

Effects of Lava flow

Answer 2

infrastructure and farmland covered in a layer of lava
very hot will destroy anything in its path

Question 3

Case study of lava flow

Answer 3

iceland 1873, molten material erupted from a fissure volcano causing 22% of pop to die from famine

Question 4

What is pyroclastic flow

Answer 4

mix of hot rock, lava ash and gas moving at a very high temp and speed in air

Question 5

Effects of pyroclastic flow

Answer 5

destroy anything in its path, caused most death as direction of path is unpredictable, most hazardous when side of volcano as closer to ground

Question 6

What hazard is a Jokulhlaup

Answer 6

A secondary hazard

Question 7

What is a Jokulhlaup

Answer 7

When an eruption under an ice sheet/ glacier causes it to melt a large volume of ice and water consequently flows downhill pushing out from under ice

Question 8

Effects of Jokulhlaup

Answer 8

extremely large floods

Question 9

spacial extent

Answer 9

how much room a hazard takes up, pyroclastic flow and gases beyond lahars and lava flows

Question 10

Shield volcanos- where do they form and what kinda eruptions

Answer 10

form at divergent (constructive) boundaries with relatively gentle and effuse eruptions

Question 11

Composite (strato) volcanos- where do they form and what do they involve

Answer 11

convergent (destructive) boundaries with pyroclastic flows and lava/ash

Question 12

Super volcanos, how to identify and requirements

Answer 12

erupt at least 1000km cubed of material, form caldera (cone shape) and less frequent

Question 13

What type of hazard is Ash fall/ tephra

Answer 13

Primary hazard

Question 14

What is Ash fall/ Tephra

Answer 14

All the pieces of all fragments of rock ejected into the air by erupting volcano

Question 15

Effects of Ash falls/ Tephra

Answer 15

Very disruptive
Can build up and cause:
-collapse of roofs
-poor visibility
-damage to crops
-respiratory problems

Question 16

Case study of Ash fall/ Tephra

Answer 16

Eyjafjallajokull (2010) caused 100,000 flights cancelled worldwide

Question 17

What type of hazard are volcanic gases

Answer 17

Primary hazard

Question 18

What are volcanic gases and what are they composed of

Answer 18

Explosive eruptions, mix of gas involves water vapour, sulphur dioxide, hydrogen and carbon monoxide

Question 19

Effect of volcanic gases

Answer 19

When they sink (after travelling) and accumulate it can be deadly

Question 20

Case study of volcanic gases

Answer 20

In 1986 in Cameroon, co2 emissions killed 1700 people

Question 21

What hazard is lahar

Answer 21

A secondary hazard

Question 22

What is Lahar

Answer 22

A mass of rock, mud and water that travels quickly down the sides of a volcano caused when an eruption melts snow and ice or due to heavy rainfall

Question 23

Effects of Lahar

Answer 23

Can erode away material and infrastructure in their path, serious economic and land damage

Question 24

Case study of Lahar

Answer 24

Killed 20,000 people in 1985 Nevado del ruiz