Module 1.4 - Volcanoes

Question 1

What is a volcano

Answer 1

a rupture in the earths crust that allows magma to flow upwards

Question 2

Where are volanoes usually located

Answer 2

along divergent/convergent boundaries or at hotspots (areas where underlying mantle is much hotter than in other areas)

Question 3

What is an ash cloud

Answer 3

a cloud of ash that forms in the air after some volcanic eruptions

Question 4

What is a magma chamber

Answer 4

contains molten rock (magma) deep within earths crust

Question 5

What is a conduit

Answer 5

a passage through which magma (molten rock) flows up in volcanoes

Question 6

What is a vent

Answer 6

an opening in earths surface through which molten rocks rise to the surface

Question 7

What is lava

Answer 7

magma coming to the surface from a volcanic eruption

Question 8

What is pyroclastic flow

Answer 8

clouds of ash and lava fragments

Question 9

What is the definiton of an erupting volano

Answer 9

the sudden occurance of a discharge of steam and volcanic material

Question 10

What is the definiton of an active volcano

Answer 10

any volcano that has erupted in the last 10000 years

Question 11

What is the definiton of an dormant volano

Answer 11

an active volcano that is not erupting, but will soon

Question 12

What is the definiton of an extinct volano

Answer 12

a volcano that has not erupted in the last 10000 years

Question 13

At what plate boundary to strato volcanoes form

Answer 13

converging subduction boundaries

Question 14

what type of lava do strato volcanoes produce

Answer 14

because the subduction forces basalt oceanic crust into the mantle the lava created is much more viscous (thick) and the flow is slower

Question 15

what type of explosion do strato volcanoes have?

Answer 15

because of the high viscosity (thickness) of the lava the volcano is explosive

Question 16

what type of form do strato volcanoes take

Answer 16

conical mountain with steep slopes, short lava flows (because of thickness) and have a crater at summit created by explosion

Question 17

At what plate boundary to shield volcanoes form

Answer 17

diverging boundaries and hotsports magma moves up through rift

Question 18

what type of lava do shield volcanoes produce

Answer 18

molten, mantel rock comes to surface (mainly granite) and has a lower viscosity so the lava flows easier

Question 19

what type of explosion do shield volcanoes have?

Answer 19

non-explosive because lava is runny and not sticky

Question 20

what type of form do shield volcanoes take

Answer 20

gently sloping, broad summits low silica lava (spread easily, low viscous - less explosive)

Question 21

Explain hot spot volcanoes (where they form how the lava comes up and island arcs)

Answer 21

hot spot forms away from plate boundaries over a mantle plume (hot columns of solid rock that rise through mantle by convection) When plume reaches base of lithosphere the magma over time plates moves but hotspot stay creating islands arcs

Question 22

more silica =

Answer 22

slower flow

Question 23

low viscousity

Answer 23

less explosive