Download Volcano Notes

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How many active volcanoes are in the world?
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About 1500
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Begin volcano video and questions
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Pick one way to trigger a tsunami (1)
◦ Include one real life example (1)
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Describe how a tsunami wave is different from a
wind wave (2)
Describe at least three ways the tsunami causes
destruction (3)
Describe at least three ways to increase your
chances of survival during the tsunami (3)
Include at least two pictures or drawings (2)
http://www.pbs.org/wgbh/nova/earth/deadli
est-volcanoes.html
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What triggers volcanic eruptions?
What is an ash cloud and how can it impact the world?
How is Yellowstone a super volcano if it’s not on a plate
boundary?
How are cosmic rays used to investigate volcanoes?
Why is the ground in Naples moving up?
What can the different volcanic gases tell us about
upcoming volcanic eruptions?
What is a “Lahar”, how are they created, and why are they
dangerous?
Can we do anything but hope these dangerous volcanoes
don’t erupt soon?
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Tsunami Questions
Volcano quiz
Final exam is next Thursday, 6/5 (20%)
◦ 50MC questions
◦ Open notebook
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Astronomy (quiz?)
Safety Video Due 6/13
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Groups of up to 4
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Nothing illegal
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4 minutes (including intro, video, outtakes,
and credits)
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Printed list of proper safety procedures
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What is an ash cloud and how can it impact
the world?
What can the different volcanic gases tell us
about upcoming volcanic eruptions?
Can we do anything but hope these
dangerous volcanoes don’t erupt soon?
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Know where and why volcanoes form.
Know the different features and types of
volcanoes.
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A rupture on the crust which allows hot lava,
volcanic ash, and gases to escape from a
magma chamber below the surface.
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Generally found at convergent and divergent
plate boundaries.
Also found at “hot spots”, located above
mantle plumes.
◦ Where magma rises to the surface
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What is a volcano?
What are three types of places where
volcanoes are commonly found?
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Thin crust from the
spreading boundary
Release in pressure
Magma rises and
forms new rock
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The center of the ridge is new rock from
rising magma
Not a line of typical volcanoes
“Black Smokers”: Deep sea vents where the
magma rises and cools to become ocean floor
Iceland is part of the ridge that is above sea
level.
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https://www.youtube.com/watch?v=y6iK19x
aYJg
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Usually between an oceanic plate and a
continental plate
The oceanic plate becomes magma as it is
run over by the continental plate
This magma tends to be very viscous and
cools at depth before reaching the surface
When it does reach the surface it creates a
volcano
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https:
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Name given to areas believed to be formed by
mantle plumes.
◦ Columns of hot material rising from the coremantle boundary in a fixed space
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https://www.youtube.com/watch?v=g7OTVU
Y_PdQ
Start 3:40
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Where does the magma come from at a
divergent boundary?
Where does the magma come from at a
convergent boundary?
Where does the magma come from at a
hotspot?
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Volcanoes are
described by their
different features.
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Volcanic
fissure vents
are flat, linear
cracks through
which lava
emerges.
https://www.youtub
e.com/watch?v=VG
3YunIcZ54
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Built by slow eruptions of highly viscous lava
They are sometimes formed within the crater
of a previous volcanic eruption (Mt. St. Helen)
Can produce violent, explosive eruptions
Generally lava does not flow far from the
originating vent.
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What is a fissure vent?
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How is a lava dome formed?
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Why are lava domes dangerous?
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Shield
Cinder Cone
Composite (Stratovolcanoes)
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Broad shield-like profile
Formed by the eruption of low-viscosity
(watery) lava that can flow a great distance
from a vent.
Generally don’t explode catastrophically
Hawaii is a chain of shield cones
Common in Iceland as well
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How are shield volcanoes formed?
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Result from eruptions of small cinders
Short-lived eruptions
Produce a cone-shaped hill 30 to 400 meters
high
Most only erupt once
May form off side of larger volcanoes
Based on satellite images they might occur on
other terrestrial bodies in our solar system
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How are shield volcanoes formed?
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What are cinder cones the result of?
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Tall conical mountains composed of lava
flows and other ejecta in alternate layers.
Different layers are made of cinders, ash, and
lava.
Cinders and ash pile on top of each other,
lava flows on top of the ash, where it cools
and hardens, and then the process repeats.
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Greater pressure build up than shield
volcanoes from the underlying lava flow
More powerful eruptions from fissure vents
and cones
Steeper than shield volcanoes
Ash produced from these have posed the
greatest volcanic hazard to civilizations.
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How are shield volcanoes formed?
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What are cinder cones the result of?
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How do the different layers of a
strato/composite volcano form?
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Supervolcanoes
Submarine Volcanoes
Subglacial Volcanoes
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Another way of classifying volcanoes is by the
composition of lava
Lava can be broadly classified into 4 different
compositions.
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Two ways
Smart Way: Wait for it to cool, pick it up, bring it
to a lab for testing.
Not So Smart Way: Get it while it’s hot!
◦ https://www.youtube.com/watch?v=egEGaBXG3Kg
◦ http://petapixel.com/2014/05/28/swimming-fire-btsvideo-qa-two-daredevil-lava-photographers/
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Erupted magma contains >63% of silica
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Highly viscous (not very fluid)
◦ Not vicious (spiteful)
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Trap gases which cause violent eruptions
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Erupted magma contains 52-63% silica
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Generally occur above subduction zones
◦ Typically formed at convergent boundaries
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Intermediate because the magma is a mixing
between felsic and mafic magmas.
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Erupted magma contains 45-52% silica
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Tend to be hotter and less viscous than felsic
lavas.
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Occur in a wide range of settings:
◦ Mid-ocean ridges
◦ Shield volcanoes
◦ Continental flood basalts (eruptions where lava covers a
very large area)
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Erupted magma contains <45% silica
Very rare, has only happened a few times in
the past 550 million years
Hottest lavas, even more fluid than common
mafic lavas
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What are the four types of lava?
What determines which type of lava a sample
is?
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http://www.nytimes.com/video/science/100
000003431211/how-it-happens-volcaniceruptions.html?playlistId=100000002963017
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A popular way of classifying volcanoes is by
their frequency of eruption.
Active
Dormant
Extinct
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Erupt frequently
◦ No agreement among scientists about this
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Volcanoes that are erupting or show signs
that it is likely to erupt
About 1,500 active volcanoes in the world
◦ About 50 of these erupt each year
◦ An estimated 500 million people live near active
volcanoes
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Kilauea, the famous Hawaiian volcano, has
been in continuous eruption for thirty years,
and has the longest-observed lava lake.
Mount Etna and nearby Stromboli, two
Mediterranean volcanoes in almost
continuous eruption since antiquity.
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Volcanoes that have erupted in recorded
history, but show no activity now are dormant
or inactive.
Can become active seemingly out of the blue.
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Vesuvius is the most infamous dormant volcano.
Yellowstone never erupted in recorded history,
but we know its recharge period is around
700,000 years.
Dormant volcanoes tend to have a worse effect
on civilizations because people are surprised
when they erupt.
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Considered to be very unlikely to erupt again
because the volcano no longer has a magma
supply.
The smaller Hawaiian islands are extinct because
they are no longer above the hot spot that
supplies the fresh magma.
Supervolcanoes sit on massive magma supplies
that can stay hot for millions of years, so many
scientists won’t consider them extinct.
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Name one example of an active, a dormant,
and an extinct volcano.
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Destroying stuff
https://www.youtube.com/watch?v=gzainwT1mr
A
https://www.youtube.com/watch?v=Fcz3vBdI7Nc
&feature=kp
https://www.youtube.com/watch?v=Zf4wKY8PJtg
Creating energy
https://www.youtube.com/watch?v=Q1UaOCe0E
CI
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Ash clouds
Earthquakes
Hot springs
Fumaroles
Mud pots
Geysers
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Consists of fragments of pulverized rock,
minerals, and volcanic glass created during
volcanic eruptions.
◦ Less than 2mm in diameter
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It can be dispersed thousands of miles away
from the volcano.
◦ Causing crops to die, flights to be cancelled, water
to be contaminated, etc.
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What happens on the ground?
https://www.youtube.com/watch?v=TK7JAKP
66kY
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A spot where hot water flows to the surface
of the Earth from the ground.
The water is heated from coming into contact
with the magma below the surface of the
Earth.
Occur all over the world.
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https://www.youtube.com/watch?v=HOuiI9N
5miY
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An opening in the Earth’s crust which emits
steam and gases.
◦ Carbon dioxide, sulfur dioxide, hydrogen chloride,
and hydrogen sulfide.
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Superheated water turns to steam as its
pressure drops when it emerges from the
ground.
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A hot spring with limited water in the form of
a pool of bubbling mud.
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The acid and microorganisms decompose
surrounding rock into clay and mud.
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https://www.youtube.com/watch?v=a9hUsVq
9q7U
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A spring characterized by intermittent
discharge of water ejected turbulently and
accompanied by steam
◦ https://www.youtube.com/watch?v=X4zA_YPCyHs
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Water in contact with the hot magma boils
and pressurizes, eventually shooting out of a
vent on the surface.
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https://www.youtube.com/watch?v=H8lF3f4R
vGo
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https://www.youtube.com/watch?v=CRoNhfL
ufDA
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Geyser Guy
◦ https://www.youtube.com/watch?v=_gyhvqbIaOE
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Describe the 6 effects of a volcano we went
over?
Pick one of the effects of a volcano we talked
about and explain what possible dangers it
poses to people.
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Pick up a piece of paper and read through the
questions.
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Complete the online activity
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Hawaii is made from which type of volcano?
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Begin volcano quiz