Volcanism

Question 1

phenomenon of eruption of molten lava

Answer 1

Volcanism

Question 2

Underground molten rocks

Answer 2

Magma

Question 3

Why does magma rise to the surface?

Answer 3

Because molten rocks are dense, they are more likely to rise to the surface due to the pressure.
A magma chamber may be squeezed by tectonic plates which will then rise because of the pressure.

Question 4

a hill, mountain, or fissure that ejects molten rocks, hot gases, and ash.
a crater formed by the removal of pre-existing materials/ejected materials.

Answer 4

Volcano

Question 5

opening of a volcano that ejects materials. It is connected to the magma chamber.

Answer 5

Vent

Question 6

long narrow cracks in the crust.

Answer 6

Fissures

Question 7

secondary vents. Only emits gases

Answer 7

Fumaroles

Question 8

circular depression over a vent.

Answer 8

Crater

Question 9

Unusually large depressions that exceed 1km in distance.

Answer 9

Calderas

Question 10

underground pool of liquid rock.

Answer 10

Magma chamber

Question 11

the most striking part.

Answer 11

Cone

Question 12

intrusive sheets

Answer 12

Sills

Question 13

the rock or magma expelled during a volcano

Answer 13

Lava

Question 14

The barrier of a volcano

Answer 14

Dikes

Question 15

pipe conveying liquid materials.

Answer 15

Conduit

Question 16

side of a volcano

Answer 16

Flank

Question 17

Highest point.

Answer 17

Summit

Question 18

Entrance

Answer 18

Throat

Question 19

composed of pulverized rock and glass that is expelled in the atmosphere.

Answer 19

Ash cloud

Question 20

chunks of lava blasted into the air.

Answer 20

Volcanic bombs

Question 21

fast moving currents of hot gasses and rock

Answer 21

Pyroclastic flow

Question 22

fragmented material

Answer 22

Tephra fall

Question 23

mudflows, mixture of volcanic debris and water.

Answer 23

Lahar

Question 24

Types of volcanoes

Answer 24

Cinder, composite, shield, volcanic domes

Question 25

aka scoria cones; simplest type. Built from ejected lava fragments. Examples: Taal and Paricutin

Answer 25

Cinder cones

Question 26

stratovolcano; Produced when viscous lava of andesite composition flows out over a long time. Examples: Mayon and Fuji

Answer 26

Composite volcano

Question 27

board and gently sloping. Formed by less viscous basaltic lava flows. Examples: Kilauea and Mauna Loa

Answer 27

Shield volcano

Question 28

aka lava dome; round, steep-sided mound.

Answer 28

Volcanic Domes

Question 29

Types of volcanic eruptions

Answer 29

Phreatic, vulcanian, strombolian, pelean, phreatomagmatic. Plinian

Question 30

driven by steam when groundwater is heated.

Answer 30

Phreatic

Question 31

results from the release of large amounts of accumulated magmatic gas.

Answer 31

Vulcanian

Question 32

lava fountains and outbursts of molten lava

Answer 32

Strombolian

Question 33

occurs when gas rich lava accumulates to form a dome.

Answer 33

Pelean

Question 34

results from the eruption of magmatic gases

Answer 34

Phreatomagmatic

Question 35

a violent explosion with voluminous ejections of pumice and ash flows

Answer 35

Plinian

Question 36

How do volcanoes form?

Answer 36

Volcanoes are formed when there is a rich source of magma on the surface or underwater.

Question 37

Where are they formed?

Answer 37

On Convergent plate boundaries, divergent plate boundaries, and hot spots

Question 38

Volcanoes are often formed here because magma is abundant in subduction zones. Subduction zones are places where a heavier plate moves under another causing it to form trenches, a long narrow depression. As one plate descends, the pressure and temperature increases causing rocks to melt and become magma and the magma will then be pushed out of the surface.

Answer 38

Convergent Plate Boundaries

Question 39

long narrow depression

Answer 39

trenches

Question 40

places where a heavier plate moves under another causing it to form trenches

Answer 40

Subduction zones

Question 41

The most active chain of volcanoes can be found in

Answer 41

the Pacific Ring of Fire.

Question 42

Volcanoes can be formed along the oceanic ridge system.

Answer 42

Divergent Plate Boundaries

Question 43

long, narrow chain of folds in the oceanic crust produced by diverging plate boundaries in the asthenosphere.

Answer 43

Ridge

Question 44

zone with weak materials below the lithosphere.

Answer 44

Asthenosphere

Question 45

a valley that separates ridges.

Answer 45

Rift

Question 46

location of active seafloor spreading located in the middle of the Atlantic Ocean.

Answer 46

Mid-atlantic ridge

Question 47

volcanic regions like the island of Hawaii.

Answer 47

Hot spots

Question 48

the resistance of fluid to flow

Answer 48

Viscosity

Question 49

Types of Magma According to Viscosity

Answer 49

Granitic, Basaltic, Andesitic

Question 50

most silica. Highest viscosity

Answer 50

Granitic

Question 51

least silica. Lowest viscosity

Answer 51

Basaltic

Question 52

inbetween

Answer 52

Andesitic

Question 53

Triggering of the eruptions

Answer 53

Landslides and earthquakes Confining pressure decreases from the rising magma Vapor pressure increases