Volcanic Hazards

Question 1

What is a volcano

Answer 1

a cone shaped structure with a central vent connected by a pipe

Question 2

other word for pipe

Answer 2

conduit

Question 3

what does the conduit do

Answer 3

connects the interior of the Earth to the surface

Question 4

What is found in the interior of the Earth

Answer 4

molten rock known as magma

Question 5

What movement causes a great build up of pressure and heat

Answer 5

when tectonic activity such as convergence or divergence takes place

Question 6

When this (previous question) happens, what happens to the magma

Answer 6

it is forced up with hot gases such as water vapour and carbon dioxide until it exits through the vent of the volcano as lava on the surface of the Earth

Question 7

difference between magma and lava

Answer 7

magma for molten rock that is underground and lava for molten rock that breaks through the Earth’s surface

Question 8

volcanoes are found near

Answer 8

the plate boundaries where plates slide beneath each other or where they move away from each other

Question 9

flanks

Answer 9

sides of the volcano

Question 10

crater

Answer 10

a funnel shaped depression at the top of the volcano

Question 11

vent

Answer 11

opening or hole through which volcanic materials are ejected

Question 12

pipe

Answer 12

the main conduit via which magma is transported through the volcano

Question 13

sill

Answer 13

a horizontal intrusion of magma within the volcano

Question 14

dike/dyke

Answer 14

a vertical intrusion which cuts through layers in the volcano

Question 15

parasitic cone

Answer 15

a smaller cone found on the flanks of the volcano

Question 16

magma chamber or batholith

Answer 16

the main reservoir where a large amount of magma is stored

Question 17

how are volcanoes formed

Answer 17

they’re formed at plate tectonic boundaries where the plates undergo different types of movements

Question 18

these different types of movements include

Answer 18

where plates collide at convergent plate boundaries resulting in the heavier plate (oceanic) being subducted below the lighter (continental) plate

Question 19

What does this subduction result in

Answer 19

the grinding of both plates…👀

Question 20

What does the grinding cause (…)

Answer 20

increased amounts of heat and pressure, causing the rock to melt into magma

Question 21

how is the molten rock stored

Answer 21

under intense heat and pressure until it finds a way to escape to the surface as a volcanic ERUPTION

Question 22

What is another way volcanoes are formed

Answer 22

at divergent plate boundaries

Question 23

What happens at divergent plate boundaries

Answer 23

the two plates (usually oceanic) move away from each other in opposite directions. the oceanic/continental crust stretches until molten rock or hot magma rises to fill the gap between the diverging plates

Question 24

when oceanic plates diverge, what occurs

Answer 24

sea floor spreading

Question 25

eg of sea floor spreading (probs dont have to learn off)

Answer 25

the Mid-Atlantic Ridge found in the middle of the Atlantic Ocean. Volcanoes have formed the island and country of Iceland

Question 26

When continental plates move apart they form

Answer 26

rift valleys e.g. the Great Rift Valley in Kenya

Question 27

the following are

Answer 27

material emitted by the volcano

Question 28

tephra

Answer 28

solid materials ejected from a volcano (ash, dust and rocks called bombs)

Question 29

tuff

Answer 29

ash and dust cemented together

Question 30

lapilli

Answer 30

small rock fragments

Question 31

lahar

Answer 31

volcanic ash saturated with water so that it moves downhill very rapidly like a mudflow

Question 32

pyroclastic flow

Answer 32

lava, cinder, ash, dust and gases carried down a hill. The gases are so hot the material glows as it moves downhill like a glowing cloud

Question 33

Life cycles of a volcano-

The volcano has how many stages

Answer 33

3

Question 34

1. Active stage

Answer 34

eruptions are still in progress

e.g La Soufriere in Montserrat

Question 35

2. Passive or Dormant

Answer 35

they have not erupted within recent times. Such volcanoes can erupt without warning such as Mt. Pelee in Martinique

Question 36

3. Extinct

Answer 36

there are no historical records of volcanic eruptions

eg the Gran Etang in Grenada

these are classified as dead volcanoes because pressure has changed inside the earth

Question 37

Are volcanoes serious potential disasters

Answer 37

yea. and so is yuh mo…

Question 38

they are found near where and can do what

Answer 38

plate boundaries and can cause so much damage when they erupt especially if they are located near communities where people live

Question 39

Some hazards include

Answer 39

those which affect the natural environment

loss of crops and vegetation, landslides, displacement of populations, air pollution

Question 40

Can volcanoes be beneficial to the human environment and this explains what

Answer 40

yes which may explain why many communities have been established at the foot of volcanoes

Question 41

benefits of volcanic activities

Answer 41

provision of rich volcanic soils which are fertile for farming
tourist attractions (geysers, hot springs- eg Dominica, St. Lucia and Grenada)
minerals (gold, zinc, silver) may be ejected during eruptions -eg in St. Lucia and dominica, there are plans to harness the energy from volcanoes

Question 42

what is this energy

Answer 42

geothermal energy which will be used to improve electricity supplies