2.a extrusive and intrusive landforms

Question 1

What are the 8 hazards produced by volcanos?

Answer 1

1. lava flows
2. pyroclastic flow
3. gas emissions
4. Tephara
5. Ash
6. lahars
7. Flooding
8. Tsunami

Question 2

Explain lava flows as a hazard produced by volcanos?

Answer 2

Basaltic lava is free flowing and can run for considerable distances - low viscosity /Andesitic lava flow - does not flow as far /Everything in the path of the lava is burned,bulldozed,buried

Question 3

Define pyroclastic flows?

Answer 3

A combination of very hot gases (500*c) + ash and rock fragments traveling at a high speed 100km/h+.

Question 4

How can pyroclastic flows be a hazard?

Answer 4

Destroys everything within their path /Damaging to people due to inhalation due to poisonous gas + ash - causing fatalities

Question 5

Explain the gas emissions hazards

Answer 5

Carbon . CO2, sulphur dioxide, carbon monoxide
* Deadly but silent threat as are not able to be seen /Sulphic acid combines with atmospheric water and acid rain is produced.

Question 6

Define the term tephra

Answer 6

Material ejected from a volcano into the air that ranges in size

Question 7

How are tephras hazardous

Answer 7

Potentially very hazardous
Can destroy crops
Columns of it can eject into the atmosphere - insanely hot

Question 8

Identify a place where tephras are located

Answer 8

Iceland

Question 9

Define the term lahar

Answer 9

A type of mudflow with consistency of wet concrete → but water is needed so when snow melts during eruption causes this rapid movement

Question 10

How can lahars be a hazard

Answer 10

Picks up rock fragments as it moves down the volcano /Speeds of 50 km / hr /Everything in its path is destroyed or buried

Question 11

explain flooding as a hazard

Answer 11

Volcanic eruptions beneath a field or glacier causes rapid melts e.g Iceland → due to this glacial melt

Question 12

Explain tsunami as a hazard

Answer 12

Violent eruption of some island mass can cause massive displacement of ocean water causing speeds of up to 600km/hr / When they break send vasts amount of energy onto shore.

Question 13

What is meant by etrusive landforms?

Answer 13

Extrusive → activity that occur on the surface of the earth

Question 14

What are the four etrusive landforms you need to know?

Answer 14

geysers / hot springs and mud pools mud volcanoes fumaroles

Question 15

What is a geysers?

Answer 15

There Is a fountain of both hot (often boiling) and cold water as well as steam ejected from the ground.
There has to be a powerful heat source beneath them relatively close to the surface and a source of water.

Question 16

Facts about geysers

Answer 16

Rarest form of geothermal activity / Can rise to over 100m in height As the water moves towards the surface pressure decreases which reduces the boiling point of the water causing the eruption

Question 17

What are the two other types of geysers

Answer 17

Fountain geysers are more violent eruptions whilst Cone geysers are where it erupts from silica and other sediments (sinter)

Question 18

Explain hot springs and mud pools

Answer 18

Natural spring where the temperature of water is above body temperature which are not explosive / Surface material is rich in permeable volcanic ash and clay and when with a source of water = mud pools

Question 19

Explain mud volcanoes landform

Answer 19

Mud pools splatter outwards to the sides which can result in the formation of ‘mini volcanoes’ 2m tall
Hot water mixes with mud and is deposited at the surface –> Tend not to be violent

Question 20

What is a fumarole?

Answer 20

Vents that give off gases - CO2, Sulphur dioxide, hydrogen sulphide & steam that occur in areas of little water but lots of heat.

Question 21

Facts about fumaroles

Answer 21

Created when super heated water reaches the surface
and Decrease in pressure changes water to steam
They are also accompanied by a roaring sound