Volcanic Hazards

Question 1

Volcanic hazards can be…

Answer 1

primary and secondary

Question 2

Primary hazards include

Answer 2

1. Tephra
2. Pyroclastic flows
3. Lava flows
4. Volcanic gases.

Question 3

Secondary hazards include….

Answer 3

1. Lahars
2. Floods
3. Tsunamis
4. Landslides
5. Climate change.

Question 4

Tephra is..

Answer 4

the general term for fragments of rock and solidified lava blasted into the air.

Question 5

Pyroclastic flows are

Answer 5

fluid mixtures of semi-solid fragments of rock and hot gases.
move similar to avalanches, up to 100km/h
can be up to 900*C

Question 6

Lava flows are

Answer 6

least hazardous and depends on distance travelled.

dangerousness depends on viscosity, temperature, silica content, gradient of flank.

Question 7

Volcanic gases can include…

Answer 7

Carbon dioxide and monoxide, hydrogen sulphide H2SO4, Sulphur Dioxide SO2 and Chloride Gases Cl2

Question 8

Lahars form when…

Answer 8

water content of pyroclastic flows increases.

contain debris from trees rocks and buildings.

Question 9

Flooding occurs when…

Answer 9

Glaciers near the erupting volcano melt and increase the discharge of rivers which burst their banks and flood the surrounding plain
e.g. the Grimsrotin glacial burst, Iceland

Question 10

Tsunamis are created as..

Answer 10

large bodies of water is displaced as a result of either a landslide, pyroclastic flows, submarine eruptions, or violent Caldera-forming events