How many active volcanoes are in the world? About 1500.

How many active volcanoes are in the world?

About 1500

Bellringer

Begin volcano video and questions

Objective

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

Know where and why volcanoes form.

Know the different features and types of volcanoes.

Objectives

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?

Mantle Plumes

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

Mid Atlantic Ridge

https://www.youtube.com/watch?v=y6iK19xaYJg

Black Smokers

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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

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

Volcanoes are described by their different features.

Volcano Features

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

Lava Dome

1. What is a fissure vent?

2. How is a lava dome formed?

3. Why are lava domes dangerous?

Checkpoint

1. Shield 2. Cinder Cone 3. Composite (Stratovolcanoes)

Types of Volcanoes

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

Shield Volcanoes

1. How are shield volcanoes formed?

Checkpoint

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

Cinder Cones

1. How are shield volcanoes formed?

2. What are cinder cones the result of?

Checkpoint

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

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

1. Supervolcanoes2. Submarine Volcanoes3. Subglacial Volcanoes

Other Types of Volcanoes

Another way of classifying volcanoes is by the composition of lava

Lava can be broadly classified into 4 different compositions.

Erupted Material

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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-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

What are the four types of lava?

What determines which type of lava a sample is?

Checkpoint

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

Name one example of an active, a dormant, and an extinct volcano.

Checkpoint

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

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Ash clouds Earthquakes Hot springs Fumaroles Mud pots Geysers

Effects of Volcanoes

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

Ash Cloud

What happens on the ground?

https://www.youtube.com/watch?v=TK7JAKP66kY

Ash Cloud

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

Grand Prismatic Spring

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

Pick up a piece of paper and read through the questions.

Bellringer

Complete the online activity

Objective

Hawaii is made from which type of volcano?

Bellringer

Begin volcano quiz

Objective

Volcano quiz