how many active volcanoes are in the world? about 1500
TRANSCRIPT
Pick one way to trigger a tsunami (1)◦ Include one real life example (1)
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)
Mini Posters (12 pts)
Volcanoeshttp://
www.pbs.org/wgbh/nova/earth/deadliest-volcanoes.html
1. What triggers volcanic eruptions?2. What is an ash cloud and how can it impact the world?3. How is Yellowstone a super volcano if it’s not on a plate
boundary?4. How are cosmic rays used to investigate volcanoes?5. Why is the ground in Naples moving up?6. What can the different volcanic gases tell us about upcoming
volcanic eruptions?7. What is a “Lahar”, how are they created, and why are they
dangerous?8. Can we do anything but hope these dangerous volcanoes don’t
erupt soon?
NOVA Video: Deadliest Volcanoes
Tsunami Questions Volcano quiz Final exam is next Thursday, 6/5 (20%)
◦ 50MC questions◦ Open notebook
Astronomy (quiz?) Safety Video Due 6/13
Grades/Time Left
Groups of up to 4
Nothing illegal
4 minutes (including intro, video, outtakes, and credits)
Printed list of proper safety procedures
Safety Video
1. What is an ash cloud and how can it impact the world?
2. What can the different volcanic gases tell us about upcoming volcanic eruptions?
3. Can we do anything but hope these dangerous volcanoes don’t erupt soon?
Bellringer – Start New
A rupture on the crust which allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface.
Volcano
Generally found at convergent and divergent plate boundaries.
Also found at “hot spots”, located above mantle plumes.◦ Where magma rises to the surface
Where do they come from?
1. What is a volcano?
2. What are three types of places where volcanoes are commonly found?
Checkpoint
Thin crust from the spreading boundary
Release in pressure Magma rises and
forms new rock
Divergent Plate Boundaries
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.
Mid Atlantic Ridge
https://www.youtube.com/watch?v=y6iK19xaYJg
Black Smokers
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
Convergent Plate Boundaries
https://www.youtube.com/watch?v=It7107ELQvY
Ring of Fire
Name given to areas believed to be formed by mantle plumes.◦ Columns of hot material rising from the core-
mantle boundary in a fixed space
Hotspots
https://www.youtube.com/watch?v=g7OTVUY_PdQ
Start 3:40
Hawaii
1. Where does the magma come from at a divergent boundary?
2. Where does the magma come from at a convergent boundary?
3. Where does the magma come from at a hotspot?
Checkpoint
Volcanic fissure vents are flat, linear cracks through which lava emerges.
https://www.youtube.com/watch?v=VG3YunIcZ54
Fissure Vents
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.
Lava Domes
1. What is a fissure vent?
2. How is a lava dome formed?
3. Why are lava domes dangerous?
Checkpoint
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
Shield Volcanoes
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
Cinder Cone
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.
Composite Volcanoes (Stratovolcanoes)
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.
Strato/Composite Volcanoes
1. How are shield volcanoes formed?
2. What are cinder cones the result of?
3. How do the different layers of a strato/composite volcano form?
Checkpoint
Another way of classifying volcanoes is by the composition of lava
Lava can be broadly classified into 4 different compositions.
Erupted Material
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-bts-vide
o-qa-two-daredevil-lava-photographers/
Sampling Lava
Erupted magma contains >63% of silica
Highly viscous (not very fluid)◦ Not vicious (spiteful)
Trap gases which cause violent eruptions
Felsic Lava
Erupted magma contains 52-63% silica
Generally occur above subduction zones◦ Typically formed at convergent boundaries
Intermediate because the magma is a mixing between felsic and mafic magmas.
Intermediate Lava
Erupted magma contains 45-52% silica
Tend to be hotter and less viscous than felsic lavas.
Occur in a wide range of settings:◦ Mid-ocean ridges◦ Shield volcanoes◦ Continental flood basalts (eruptions where lava covers a
very large area)
Mafic Lava
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
Ultramafic Lava
http://www.nytimes.com/video/science/100000003431211/how-it-happens-volcanic-eruptions.html?playlistId=100000002963017
New York Times
A popular way of classifying volcanoes is by their frequency of eruption.
Active Dormant Extinct
Volcanic Activity
Erupt frequently◦ No agreement among scientists about this
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
Active Volcanoes
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.
The Most Active Volcanoes
Volcanoes that have erupted in recorded history, but show no activity now are dormant or inactive.
Can become active seemingly out of the blue.
Dormant Volcanoes
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.
Famous Dormant Volcanoes
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.
Extinct Volcanoes
Destroying stuff https://www.youtube.com/watch?v=gzainwT1mrA https://
www.youtube.com/watch?v=Fcz3vBdI7Nc&feature=kp
https://www.youtube.com/watch?v=Zf4wKY8PJtg Creating energy https://www.youtube.com/watch?v=Q1UaOCe0ECI
Uses of Lava
Consists of fragments of pulverized rock, minerals, and volcanic glass created during volcanic eruptions.◦ Less than 2mm in diameter
It can be dispersed thousands of miles away from the volcano.◦ Causing crops to die, flights to be cancelled,
water to be contaminated, etc.
Ash Cloud
What happens on the ground?
https://www.youtube.com/watch?v=TK7JAKP66kY
Ash Cloud
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.
Hot springs
https://www.youtube.com/watch?v=HOuiI9N5miY
Snow Monkeys
An opening in the Earth’s crust which emits steam and gases.◦ Carbon dioxide, sulfur dioxide, hydrogen chloride,
and hydrogen sulfide.
Superheated water turns to steam as its pressure drops when it emerges from the ground.
Fumaroles
A hot spring with limited water in the form of a pool of bubbling mud.
The acid and microorganisms decompose surrounding rock into clay and mud.
https://www.youtube.com/watch?v=a9hUsVq9q7U
Mud pots
A spring characterized by intermittent discharge of water ejected turbulently and accompanied by steam◦ https://www.youtube.com/watch?v=X4zA_YPCyHs
Water in contact with the hot magma boils and pressurizes, eventually shooting out of a vent on the surface.
Geysers
https://www.youtube.com/watch?v=H8lF3f4RvGo
https://www.youtube.com/watch?v=CRoNhfLufDA
Geyser Guy◦ https://www.youtube.com/watch?v=_gyhvqbIaOE
BeeHiva Geyser and Old Faithful
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.
Checkpoint - Collected