Activity 1
All about Volcanoes
The basics
About this unit
Volcanoes in Tucson: how did A-Mountain form?
You’re going to investigate what Tucson was like when it was a
hotbed of volcanic activity around 27 million years ago. From your
own research you’ll figure out how A-Mountain formed. But first we
need to cover some background information. In this unit, you will:
✓ Review the basics of volcanoes (Activity 1)
✓ Research an active volcanic system (Activity 2)
✓ Study some actual volcanic rocks (Activity 3)
Who Cares?
A January 20, 2002 CNN Headline described the eruption of Mount
Nyiragongo in the Democratic Republic of Congo:
“Lava edged with black crust inched through the eastern
Congolese city of Goma on Saturday, nearly two days after
Mount Nyiragongo erupted, killing more than 40 people and
forcing thousands to flee.”
What caused these deaths and why?
? Above. The World Health
Organization’s compound in
Goma. AP photo from
CNN.com
Why was the death toll so small for a city of roughly half a million
residents?
What kinds of eruptions would have caused more deaths? For example, when Vesuvius erupted in 79 AD, debris buried the town of
Pompeii, killing 3500 people.
Getting Down to Business
The questions in this exercise help you fill out the chart on the
following page that will be your primary resource for information on
volcanoes. Use the internet and any reference materials provided by
your teacher to get the necessary information for your chart. Be as
thorough and detailed as you can here; it will make the rest of the
volcano research much easier.
4
A Sense of place · Earth and Environmental Science in the Community
Type
Strato or
Composite
Cinder
Cone
Shield
Giant
Caldera or
Rhyolite
Caldera
Complex
Fissure or
Flood
Basalts
1 - Shape
2 - Eruption Style
3 - Lava Type
4 - Hazards
5 - Rocks
Columns 1 and 2: Volcano Shape and Eruption Style
Use the following websites for reference:
http://www.cotf.edu/ete/modules/volcanoes/vtypesvolcan1.html
http://volcano.und.nodak.edu/vwdocs/vwlessons/volcano_types/type_can.htm
For each of the 5 volcano types listed in the chart fill out Columns
1 and 2.
Column 1
Shape (column 1)
Describe what the volcano type looks like. Are these volcanoes usually high mountains with snowy peaks or flat features? Where are
these kinds of volcanoes are usually found? Draw a little cartoon it if
helps you remember the shape.
Column 2
Eruption style (column 2)
When these volcanoes erupt, what is it like? Is there a lot of lava,
gas or ash? Is the eruption violent or calm? Is it a big or small
event? Would you feel safe watching the volcano erupt close-up or
would you want to be far far away?
Column 3
Column 3: Lava Type
Use the following website for reference:
http://www.cotf.edu/ete/modules/volcanoes/vtypeslava1.html
The type of lava (or magma) determines the way that a volcano will
erupt. Once you learn about lava types, assign a lava type to each
volcano type. You won’t find the answers in the reading; you’ll have
to connect what you learn about lava type to what you know about
volcano shape and eruption style.
1. a) In one sentence, what is viscosity?
b) What word that you know would describe your definition
of viscosity?
2. High viscosity will make lava flow faster / slower (circle one)
3. Silica makes a lava more / less viscous (circle one)
A Sense of place · Earth and Environmental Science in the Community
5
? Hint: think about shaking
a bottle of soda vs. shaking a
bottle of milk and opening the
cap, which one will explode?
4. Gas in lava makes it more / less explosive (circle one)
[See hint at side]
5. Describe the behavior of the lava with the following features:
a. High viscosity and low gas content:
b. High viscosity and high gas content:
c. Low viscosity and low gas content:
d. Low viscosity and high gas content:
? Above. Mt. St. Helens 1980
eruption. USGS photo.
Lava types
?
?
?
?
High viscosity & low gas
High viscosity & high gas
Low viscosity & low gas
Low viscosity & high gas
Column 4
In Column 3, write the lava types that would create the eruption
types listed in Column 2.
Use the combinations of high/low viscosity and high/low gas content
as your lava types [see sidebar]. Remember that some of the volcano
types may have multiple eruption styles and therefore have more
than one lava type.
Column 4: Volcanic hazards
Use the following website for reference:
http://www.cotf.edu/ete/modules/volcanoes/vhazards.html
Lava flows, ash flows, ash falls, earthquakes, tidal waves, poisonous
gases, mudflows, rock avalanches and explosive blasts cause a lot
of damage.
For each hazard, think about the kind of volcano that produces it.
In Column 4 of the chart list the potential hazards associated with
each volcano type - there’s often more than one.
Column 5
6
Column 5: Rocks
What kinds of rocks do each of these volcanoes produce? The answers
might not be obvious now; write down what you do know, include
your guesses, and you can complete this column later.
A Sense of place · Earth and Environmental Science in the Community