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ESCI1000 Natural Hazards and Disasters > Test 2: Volcanism > Flashcards

Test 2: Volcanism Flashcards

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1
Q

What are Pyroclastic Materials?

A

Magma fragments that are explosively ejected by volcanoes, most are solid.

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2
Q

Which Volcano?

Rhyolitic lava flows-most viscous
Very Explosive

A

Lava Domes

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3
Q

Which Volcano?

Layers of lava flows and pyroclastic debris
Steep Cone Shaped
Intermediate compositions-andesite
Explosive
“Ring of Fire”`
A

Composite Volcanoes

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4
Q

Which Volcano?

```
Gentle slopes and rounded shapes
Basaltic lava flows
Non-Explosive
Hawaiian Volcanoes
Komotilite
~~~

A

Shield Volcanoes

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5
Q

Which Volcano?

Pyroclastic materials
Steep cones
Rarely exceed 400 m high

A

Cinder Cones

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6
Q

True or False?

The shape and eruptive style of volcanoes are related to the chemistry and viscosity of their magmas.

A

True

The shape and eruptive style of volcanoes are related to the chemistry and viscosity of their magmas.

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7
Q

Rhyolitic lava flows:

A

Creates Lava Dome
Lava Dome holds in gases
Flows have broken and blocky surfaces

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8
Q

Andesitic lava flows:

A

Flows slowly
Cone shape
Made up of Pyroclastic and lava

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9
Q 
Basaltic lava flows:
Flows fast (30-50km/hr)
A

Flows fast (30-50km/hr)

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10
Q

Komatiite lava flows:

A

Has not erupted in about 2.5 billion years

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11
Q

Silica Content

Rhyolite:

A

High silica content (70-75%)

High Viscosity

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12
Q

Silica Content

Andesite:

A

Intermediate silica content (60-65%)

Intermediate Viscosity

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13
Q

Silica Content

Basalt:

A

Low silica content (50-55%)

Low Viscosity

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14
Q

Silica Content

Komatiite:

A 
Limited Silica (Below 40%)
Very Low Viscosity
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15
Q

Fine: (No big crystals) (It’s lave) (Came to the surface) (Cooled first, causing crystals not being able to grow)

Extrusive Igneous Rock

A

Basalt, Andesite, Rhyolite, Komatiite

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16
Q

Course: (Big Crystals) (Didn’t come to the surface)

Intrusive Igneous Rock

A

Granite, Diorite, Gabbro, Peridotite

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17
Q

What does Viscosity affect?

A

Viscosity affects the flow of lava and therefore the shape of the resulting volcano

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18
Q

In explosive eruptions, _____is ejected

A

In explosive eruptions, tephra is ejected

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19
Q

What is an accumulation of tephra called?

A

An accumulation of tephra is a Pyroclastic deposit

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20
Q

What is the term for anything that explodes out of the volcano?

A

Pyroclastic is anything that explodes out of the volcano

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21
Q

Molten rock material below the earth’s surface

A

Magma

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22
Q

Magma turns into a liquid when the surface is reached, creating lava

A

Lava

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23
Q

The viscosity of Magma is controlled by ______?

A

The viscosity of Magma is controlled by Silica Content

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24
Q

More Silica causes a ______explosion

A

More Silica causes a bigger explosion (Builds up pressure)

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25
Less Silica makes for a ______explosion
Less Silica makes for a smaller explosion
26
How do we have magma?
Decompression (Weight onto of it, prevents it from being liquid) Addition of volatiles (Adding water breaks chemical bonds, creating fluid) Addition of heat (When magma comes up it warms adjacent material, turning it into liquid)
27
The tectonic setting determines the type of volcano Mid-ocean ridges, subduction zones, hot spots Mixing of Basalt and Granite create andesite which makes cone volcanoes
Subduction Zones
28
The tectonic setting determines the type of volcano Mid-ocean ridges, subduction zones, hot spots One section is moving one way and another section is moving a different way, the magma pushes through the weak spot creating lava.
Mid-Ocean Ridges
29
The tectonic setting determines the type of volcano Mid-ocean ridges, subduction zones, hot spots Magma is stationary, but the plates are moving so there is a build-up of magma pressure which creates small islands.
Hot Spots
30
Where does the Ring of Fire surround?
The Ring of Fire surrounds the Pacific Ocean. (Surrounds Pacific Ocean) (Subduction zones)
31
How many of all active volcanoes on land are located along the Ring of Fire which surrounds the Pacific Ocean?
2/3
32
Popular Volcanoes Still active (Pompeii)
Mount Vesuvius, Italy
33
Popular Volcanoes “Year without summer” (Ash shot in the air everywhere)
Tambora, Indonesia
34
Popular Volcanoes | 57 people died) (Internal Explosion
Mount St Helens, United States
35
Popular Volcanoes | Airline disaster, ash coverings in sky
Mt. Eyjafjallajökull, Iceland
36
What are the volcanoes in Japan, Mexico, the Philippines, and Indonesia known as?
(Killer Volcanoes)
37
How many volcanoes erupt each year on Earth?
50-60 volcanoes erupt each year
38
Where are the most active volcanoes located in our solar system?
Jupiter's moon - IO has the most active volcanoes
39
Tidal Forcing:
Moon’s gravitational pull on a planet Jupiter's mass is so massive that it squeezes the moon (IO), it heats up the moon causing lava flows.
40
Where is the largest volcanic mountain?
Olympus Mons has the largest volcanic mountain (Mars) While Earth has more volcanic features, Mars has the largest Magma pushes and silicifies, this creates a large pile up creating big volcanic features. Volcanoes - Dormant
41
True or False: | All volcanoes are destructive
False: | Not all volcanoes are destructive
42
True or False: | Pyroclastic material is the most dangerous
True | Pyroclastic material is the most dangerous
43
How to get an accurate representation of the surface on Venus?
Radar can go through cloud cover (Gives an accurate representation of the surface)
44
How many major volcanoes or volcanic features are there on Venus?
1,600 major volcanoes or volcanic features
45
Is volcanism still on Venus?
Evidence shows that in the volcanic mountains there is still heat, meaning volcanism might still be on Venus.
46
What are volcanic gases primarily made up of?
Water Vapor (lesser amounts of carbon dioxide)
47
Craters:
Depressions formed by explosions or collapse of volcano top. (1km wide)
48
Calderas:
Volcano colossus into magma chamber following violent eruptions (thousands of metres across, hundreds of metres deep).
49
Lava Tubes:
Forms a crust which silicifies, causing the creation of a tunnel (50 km/hr)
50
Vents:
Any opening for lava and debris Can produce flood basalts Both on water and on land (Along mid-ocean ridge)
51
Hot Springs:
Hot rocks heat groundwater; discharge at the surface | Blue Lagoon
52
Geysers:
Groundwater boils, erupting at the surface. Water turns into steam and erupts Yellowstone national park
53
Pyroclastic Sheet Deposits:
Huge sheet-like eruptions of pyroclastic materials
54
Where would you find Lava Lakes?
In Africa
55
Erupt beneath or against glaciers Subglacial volcanoes erupt, rapidly melting ice and produce huge floods known as Jokulhlaups Huge flood from glacier volcanoes (Iceland, Mt. Garibaldi)
Ice Contact Volcanoes:
56
Volcanic Hazards Primary Effects:
Lava flows, ashfall, volcanic bombs, pyroclastic flows, pyroclastic surges, lateral blast (Mt.St.Helens), and poisonous gases.
57
Volcanic Hazards Secondary Effects:
Lahars, debris avalanches, landslides, groundwater and surface contamination, floods, fires, and tsunamis.
58
The size of an eruption can be quantified using a scale called the ______?
Volcanic Explosivity Index (VEI)
59
Volcanic Hazards: Ash
Ash is blown high into the air and falls onto areas. Ash can cause its own lightning from rubbing against each other. Causes health hazards (It can burn you) (Mt. Eyjafjallajokull)
60
Causes of volcanic ash
Vegetation Destroyed Contaminates Surface Water Damage to buildings Aircraft Engine Failure
61
British Airways Flight 009:
Flew into a cloud of volcanic ash (Mt. Galunggung near Jakarta, Indonesia) All 4 Engines went out
62
Biggest flight distribution since 9/11 | The ash plume drifted between 6,700 m and 11000m (2000 km away)
Mt. Eyjafjallajokull:
63
Occurs when magma reaches the surface | Can move slowly or rapidly depending on viscosity and temperature
Lava Flows:
64
What is the most common lava flow?
Basaltic lava flows are the most common
65
Types of Lava Flows Pahoehoe:
Hardens with a smooth ropy texture | Travels at speeds up to a few kilometres per hour
66
Types of Lava Flows Aa:
Harden's with a rough, blocky texture | More vicious travels at rates of a few metres per day
67
3 ways to Divert Lava Flows:
Bombing: Hydraulic Chilling: Wall Construction:
68
Diverting Lava Flow: Bombing:
Block channels to cause low flows to take a less damaging route
69
Diverting Lava Flow: Hydraulic Chilling:
Water used to chill and control lava flows (Iceland)
70
Diverting Lava Flow: Wall Construction:
Walls are used to redirect lava flows
71
What is the most dangerous lava flow?
*Pyroclastic flows are most dangerous (400 km per hour) Pompeii*
72
Avalanches of hot rock, Ash, volcanic rock fragments
Flows
73
Dense clouds of hot gas and rock debris produced by explosive interaction of water and magma
Surges
74
Nuée Ardente:
A turbulent, fast-moving cloud of hot gas and ash erupted from a volcano
75
Lateral Blasts:
Rock fragments, gas, and ash that are blown horizontal from the side of the volcano For example: Mount St. Helens Lahars: Aftermath of Mt. St. Helens Forecast eruptions but can’t predict them
76
Who believed the situation was over-exaggerated and ended up dying from not evacuating?
Harry Truman (Spirit Lake Lodge)
77
Poisonous Gas Odourless, heavy gas that can displace breathable air.
Carbon dioxide (CO2):
78
Poisonous Gas Odorous gas that causes acid rain and can contaminate rock and soil.
Sulphur Dioxide:
79
Lahars?
Large amounts of loose volcanic ash and other pyroclastic material become saturated with water and rapidly move downslope
80
Why Do People Live Near Volcanoes?
``` Place of birth On some islands, all land is volcanic Fertile land for farming Believe Interruption is unlikely Unaware of risk Economic limitations ```
81
Natural Service Functions:
Volcanic Soils: Good for coffee, maize, pineapples, sugar cane, and grapes Geothermal Power: Can create energy for nearby urban areas Mineral Resources: Gold, silver, etc. And non-metallic rocks Used for soap, building stone, aggregate for roads, railroads, etc Recreation: Health Spas in Hot Springs Hygiene, snow sports, and education Kilauea National Park Creation of New Land: Hawaiian Islands
82
Is it possible to Forecast Eruptions?
YES! Monitoring involves recording and analyzing both physical and chemical changes at volcanoes. Tiltmeters and geodimeters to detect changes in slope, elevation, and shape. Seismometers to detect harmonic tremors Gas emissions, thermal, magnetic and hydrologic monitoring are also measured

ESCI1000 Natural Hazards and Disasters (5 decks)

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