Vulcanicity

Question 1

Define vulcanicity

Answer 1

Most commonly associated with natural hazards which has hazards and benefits

Question 2

Define a hazard and give some examples

Answer 2

Something that poses a threat to human life
Lava flows burn and bury crops
Ash falls and ruins crops
Volcanic melting of snow creates dangerous Lahars

Question 3

What are some benefits of vulcanicity

Answer 3

Lava flows can create land

Lava and ash weather into fertile soil

Question 4

Describe the distribution of volcanoes

Answer 4

-along plate boundaries
-long narrow belts
-linear patterns
-Pacific ring of fire
-oceanic ridges-mid Atlantic ridge Iceland
-rift valleys- great African Rift Valley (continent ripping apart) my Kenya
Subduction zones
Over hot spots
-

Question 5

What are volcanoes

Answer 5

Openings in the earths crust through which lava, ash and gases erupt.

Question 6

What is molten rock under the surface called

Answer 6

Magma

Question 7

What is it called once manga is ejected

Answer 7

Lava

Question 8

What are volcanoes built upon

Answer 8

The accumulation of their own erupt ice products:lava

Question 9

Volcanic frequency

Define active, dormant and extinct

Answer 9

A- erupted in living memory
D-erupted in historical records
E-will not erupt again

Question 10

Constructive plate margins 
Type of magma 
Characteristics 
Type of eruption 
Materials erupted 
Frequency 
Form

Answer 10

Basaltic 
Runny, less viscous 
Little violence 
Mainly lava 
Regular and can be continuous 
Shield volcano

Question 11

Destructive plate margin
Type of magma 
Characteristics 
Type of eruption 
Materials erupted 
Frequency 
Form of the volcano

Answer 11

Acidic (andesitic) 
Slow flowing, viscous
Potentially explosive 
Lava bombs, ash 
Long dormant periods
Composite cone

Question 12

Extrusive volcanic features

Answer 12

Magma cools and crystallises from surface lava,

In contrast with the air lava cools quicker than magma

Question 13

Gaseous emissions

Answer 13

Dominated by steam
Highly dangerous
Often superheated
Carbon monoxide

Question 14

Solids

Answer 14

Ash, dust and glassy cinders.

Blocks of material- shattered remains of solidified lava

Question 15

Liquids

Answer 15

Include lava bombs which solidify in mid-air

Question 16

Name the three firms of lava

Answer 16

Basaltic
Andesitic
Rhyolithic

Question 17

Basaltic lava

Answer 17

• formed from upward movement of manta, material
• found along spreading ridges and hot spots
• magma is low in silica- more fluid
• gas bubbles expand on the way up
• prevents sudden explosive activity

Question 18

Andesitic lava

Answer 18

• formed at destructive plate margins where crust is being destroyed
• silica-rich magma +very viscous
• often solidifies before reaching the surface
• build up of pressure and a violent explosion

Question 19

Rhyolithic lava

Answer 19

• formed at destructive and collisions margins
• silica-rich magma and is very viscous
• often solidifies before reaching the surface leading to build up of pressure and a violent explosion

Question 20

Major extrusive landforms

And name all the different types

Answer 20

• volcanoes
• fissure
• shield
• composite
• acid/dome
• caldera

Question 21

Fissure volcano

Answer 21

• rock type- basaltic
• location- rifts and early constructive margins
• eruptions- gentle
• occur where there is a long crack in the crust which allows lava to spill out onto a large area
• results in extensive flat features

Question 22

Shield volcanoes

Answer 22

• rock type- basaltic
• location- hot spots and where oceanic meets oceanic
• -eruptions gentle
• gentle slopping sides (5/10)

Question 23

Composite cone volcanoes

Answer 23

• rock type- andesitic
• location- destructive margins
• eruptions- explosive and unpredictable
• steep sides
• layers of ash

Question 24

Acid or dome volcanoes

Answer 24

• rock type: rhyolitic
• location: continental crust
• eruptions: explosive
• slopes are steep and convex

Question 25

Caldera

Answer 25

- rock type : andesitic - location: destructive margins - eruptions: very explosive - build up of gases - big crater where later eruptions may make smaller cones

Question 26

Ash and cinder cones

Answer 26

- simplest form of a volcano - formed from ash, volcanic bombs and cinders - gas charged lava is blown violently into the air and breaks into small fragments that solidify

Question 27

Classification of violence of eruption ``` I H S V V P P ```

Answer 27

``` Icelandic (I) Hawaiian (HATE) Strombolian (SILLY) Vulcanian (VIOLENT) Vesuvian (VOLCANOES) Peléean (PLAYING) Plinian (PEEWEE) ```

Question 28

Which classification of volcanoes are basaltic and have a steady flow

Answer 28

Icelandic Hawaiian

Question 29

Which classification of volcanoes have thicker basaltic lava with frequent explosive eruptions

Answer 29

Strombolian

Question 30

Which classification of volcanoes has basaltic, andesitic and rhyolitic lava and are less frequent but very violent

Answer 30

Vulcanian Vesuvian

Question 31

Which classification of volcanoes has basaltic andesitic and rhyolitic lava with very violent eruptions

Answer 31

Peléean Plinian

Question 32

What are some of the minor forms of volcanic activity

Answer 32

Geysers Fumaroles Hot springs Boiling mud

Question 33

What is a geyser and describe it

Answer 33

An intermittent, forceful discharge of superheated water ejected from the surface. Even with no volcanoes water can be heated Water is heated through contact with hot rocks Pressure builds until explosive eruption takes place Refills with water Cycle repeated

Question 34

What is a fumarole and describe it

Answer 34

Found in areas where superheated water turns into steam Associated with both active and dormant volcanoes Mainly steam Yellow deposits of sulphur

Question 35

What are hot springs and boiling mud

Answer 35

Hot springs are not under pressure so don't explode Common in Iceland - tourist attraction Some are Alcibiades and some are alkaline Hot water on its way up mixes with mud and minerals near the surface and a boiling mud volcano may form

Question 36

Intrusive volcanic landforms: Magma

Answer 36

Magma cools crystallises and solidifies into igneous rocks below the surface Slow cooling results in large interlocking crystals May become part of the landscape and then may be eroded removing overlying rocks

Question 37

Intrusive volcanic landforms: What and how are batholiths formed

Answer 37

Formed deep below the surface Large masses of magma cool and solidify Magma cools slowly large crystals formed in the rock Dome shaped and exposed by later erosion Can be several hundreds of kilometres in diameter Areas surrounding can be altered by heat and pressure

Question 38

Intrusive volcanic landforms: Dykes

Answer 38

Vertical intrusions with horizontal cooling cracks Cut across the bedding plane Occur in groups= dyke swarms Erosion of surrounding rocks can lead to exposed dykes

Question 39

Intrusive volcanic landforms: Sills

Answer 39

Horizontal intrusions along the lines of the bedding planes of pre existing rocks Vertical cooling cracks Great Whin sill Made up of dole rite

Question 40

Intrusive volcanic landforms: What are surrounding rocks known as

Answer 40

Country rocks