Chapter 4- Valcanos

Question 1

Atmosphere

Answer 1

Originally created from gasses released from volcanic eruption

Question 2

Hydrosphere

Answer 2

Produced by condensation of volcanic water vapor.

Question 3

Hydrosphere

Answer 3

Produced by condensation of volcanic water vapor.

Question 4

Biosphere

Answer 4

Both positively✔️ and negatively❌️ influenced by volcanism
✔️-Lava flows and ash weather to produce fertile soils
❌️-Violent eruptions can destroy nearly all life in their paths.
❌️- Large amounts of ash and volcanic gasses in the atmosphere can trigger rapid climate changes and contribute to mass extinctions

Question 5

Volcanism

Answer 5

Occurs when magma makes it’s way to the Earth’s surface

Question 6

Volcanos

Answer 6

Landforms formed by the extrusion of lava

Question 7

Volcanos

Answer 7

Landforms formed by the extrusion of lava

Question 8

Lava

Answer 8

Produced when magma reaches Earth’s surface

Question 9

Explosive eruptions

Answer 9

Produces rapidly cooled rock fragments called pyroclasts

Question 10

Pyroclasts

Answer 10

Size can range from dust (ash) to boulders (blocks and volcanic bombs)

Question 11

Effusive eruptions

Answer 11

Calm oozing of magma out of the ground (flowing lava) (volcanos in Hawaii)

Question 12

Creation of land

Answer 12

Lava flows build up volcanic islands (Hawaii)

Question 13

Geothermal Energy

Answer 13

Underground heat generated by igneous activity

Question 14

Effect on Climate

Answer 14

Very large eruptions can result in measurable global cooling resulting in crop failures and famines.

Question 15

Violence of eruptions is controlled by

Answer 15

-Dissolved gasses in magma
-Ease or difficulty of gasses escaping to atmosphere

Question 16

Viscosity

Answer 16

A fluids resistance to flow
-higher silica contents produce higher viscosities
-Cooler lavas have higher viscosities
-Amount of dissolved gases, the more dissolved gases,the more fluid the lava.

Question 17

Mafic Lava Flows

Answer 17

Low viscosity and flows easily
(Pahoehoe, A’a, Lava Tube)

Question 18

Flood Basalts

Answer 18

Very low viscosity and flows very easily frome erupting fissures

Question 19

Columnar Jointing

Answer 19

Parallel mostly six-sided vertical columns

Question 20

Submarine Lava flows

Answer 20

Pillow structure formed as lava flows into water.

Question 21

Intermediate and Felsic Lava Flows

Answer 21

Thicker viscous lavas that flow short distance

Question 22

Pyroclastic Materials

Answer 22

Dust, ash, cinders, lapillus, blocks, and volcanic bombs

Question 23

Pyroclastic Flows

Answer 23

Mixture of gas and pyroclastic debris that flows rapidly down slope.

Question 24

Shield Volcanoes

Answer 24

-Broad and gently sloping
-Composed of solidified basaltic lava flows
-flows often contain lava tubes

Question 25

Cinder cones

Answer 25

-Small and steeply sloping -composed of a pile of loose cinders; basalt is common.

Question 26

Composite Valcanoes

Answer 26

-moderately to steeply sloping -constructed of alternating layers of pyroclastic debris and solidified lava flows -composed primarily of intermediate composition volcanic rocks (Andesite) -Most common type of volcano on convergent plate boundaries -Mainly located around Pacific Ocean (Ring of fire) and Mediterranean sea.

Question 27

Lava Domes

Answer 27

-extremely high viscosity -degassed -felsic lavas (Often glassy, obsidian)

Question 28

Calderas

Answer 28

-volcanic depression of at least 1km in diameter -result of very violent eruptions (Crater Lake in Oregon)

Question 29

Volcanic hazards

Answer 29

-Pyroclastic flows: account for the largest number of deadly events (Pompeii) -volcanic gases: Carbon dioxide (Nyos Cameroon) -volcanic mudflow: Lahars (Armero Colombia -Indirect hazards: famine and lightning -Eruption times correspond with largest mads extinction events

Question 30

Volcanos status

Answer 30

Approximately 1,500 active volcanos worldwide

Question 31

Active volcano

Answer 31

Currently or recently eruptive (About 500 In world today)

Question 32

Dormant volcano

Answer 32

Hasn't erupted I'm thousands of years, but is expected to erupt in the future

Question 33

Extinct volcano

Answer 33

Hasn't erupted in many years and shows no signs of any future eruptions

Question 34

Volcanic activity at divergent Boundaries

Answer 34

-decompression melting -effusive eruptions of basalt magmas and pillow lavas -formation of most of the sea floor -mid-oceantic ridges, iceland

Question 35

Volcanic activity at convergent boundaries

Answer 35

-Most large well known volcanoes -explosive composite volcanoes -viscous andesitic lavas

Question 36

Within plate volcanic activity

Answer 36

-Mantle Plumes (hot spots): Hawaii, Yellowstone -Basaltic magma/lava