So You Want to see a Super Volcano?

So You Want to see a Super
Volcano?
Types of Lava
„ Mafic
„ high
Mg and Fe content, dark color, runny
lava
„ Felsic
„ high
feldspar and Si content, light color,
viscous/thick lava
How do volcanoes affect human
life?
Climate
Crop productions
Property damage
Health risks
Fatalities
Any others?
VEI Scale
VEI
Description
Plume Height
0
non-explosive
< 100 m
1
gentle
2
Volume
Classification
How often
1000s m3
Hawaiian
daily
100-1000 m
10,000s m3
Haw/Strombolian
daily
explosive
1-5 km
1,000,000s m3
Strom/Vulcanian
weekly
3
severe
3-15 km
10,000,000s m3
Vulcanian
yearly
4
cataclysmic
10-25 km
100,000,000s m3
Vulc/Plinian
10's of years
5
paroxysmal
>25 km
1 km3
Plinian
100's of years
6
colossal
>25 km
10s km3
Plin/Ultra-Plinian
100's of years
7
super-colossal
>25 km
100s km3
Ultra-Plinian
1000's of years
8
mega-colossal
>25 km
1,000s km3
Ultra-Plinian
10,000's of years
Displaced Material=Volume
„ All the “stuff” that
comes out of a
volcano:
† Gas
† Ash
† Pumice
† Lava
† Pyroclastic flow
† Etc.
1
2
3
4
5
6
Volcano
7
8
9
10
(1902)
0.9
Pelee
(1707)
1.0
St. Helens
(1980)
1.3
St Helens
2.0
Fugi (1500)
(1104)
2.7
Hekla
(79)
3.3
Vesuvius
(1900 BC)
10.0
St Helens
(1883)
Kraktoa
(1912)
Katmai
(4600 BC)
Mazama
(1815)
Tambora
Volume (Cubic Kilometers)
Displaced Material
90.0
80.0
80.0
70.0
60.0
50.0
40.0
40.0
30.0
30.0
20.0
20.0
0.3
0.0
11
Human F at alit ies
40,000
36,000
35,000
30,000
30,000
25,000
20,000
Series1
20,000
15,000
12,000
10,000
4,000
5,000
2,000
1,584
60
0
Krakatoa
(1883)
Mount Pelee Mount Etna
(1902)
(1669)
Tambora
(1815)
Mount
Vesuvius
(1631)
Mount
Vesuvius
(AD 79)
Mount
Agung
(1963)
Mount St.
Helens
(1980)
-only deaths due to single event, does not
include famine or disease after
Examples of Displaced material
What If…
„
There is a “new” hot spot in lower Montana
„
It is called Super Zit
„
„
Same hot spot that used to be in NE Nevada
and has arched across southern Idaho
Past Yellowstone
SUPER ZIT
Do we need to worry about
an eruption like Yellowstone
or Super Zit?
What natural disasters do we need to
worry about?
What plans do we need to create to
deal with such disasters?
How can we prepare?
zAs an individual?
zAs a city?
zAs a state?
zAs a nation?
Name: ___________________
Date: ______________
Comparing volcanoes is very difficult because of the many different types of
volcanic eruptions. Geologists have devised the Volcanic Explosivity Index (VEI) in
an attempt to rate volcanoes on a single universal scale. Read the explanation above
the VEI scale. Then use the bar graph showing the displaced material and the VEI
index to answer the following questions.
1.
Where do each of the following volcanoes fit on the VEI scale:
Mt. St. Helens (1980)Tambora (1815)Krakatoa (1883)Vesuvius (AD 79)Pelee (1902)2. What is the relationship between the displaced material and the magnitude (VEI
rating) of a volcano?
3. The May 18th eruption of Mt. St. Helens ejected 1 km³ of material. How many
more times displaced material did each of the following volcanoes erupt:
KrakatoaTambora4. How much less material was ejected from Pelee then the May 18, 1980 eruption
of Mt. St. Helens?
Name: ___________________
Date: ______________
Use the bar graphs showing Displaced Material and Human Fatalities to answer the
following questions.
5. How many people were killed in the eruption of Krakatoa?
How many people were killed in the 1980 eruption of Mt. St. Helens?
6. Explain why the numbers of fatalities do not increase with size of eruption.
Include in your answer 3 factors that may affect fatalities due to volcanic
eruptions?
Match the volumes to the eruptions they represent by filling in the blanks using the
table below. *Note they are in cubic miles.
Volcano
Mt. St.
Helens 1980
Displaced
Material
0.24 cubic
miles
Krakatoa
4.3 cubic
miles
Tambora
36 cubic
miles
Yellowstone
caldera
630,000
years ago
240 cubic
miles
7. According to the information above, how many times more displaced material
erupted from Yellowstone (2 million years ago) than erupted from Krakatoa?
(Show your work)
Name: ___________________
Date: ______________
Let’s make our own docudrama! Suppose a new hot spot is discovered east of Idaho
in the southern part of Montana. Geologists are just starting to research this new
hot spot. They have not disclosed much information about this new find because
they want to be sure of their data before they publish it. Based on our knowledge of
volcanoes, we can decipher the available information to better understand this
“new” hot spot.
8. Think about the volcanic rocks that we have observed so far in this class.
a. Was the magma that produced this rock mostly mafic or felsic?
b. How can you tell?
9. The estimated amount of material within the hot spot is just over 20,000 km³ and
is located 5-6 km under the surface. Based on the rock from #8 and your
knowledge of volcanism, what kind of eruption could this hot spot produce? (use
the descriptions found in the VEI table)
10. Use the map on the back of this page to answer the following questions:
a. Use an arrow on the map to show the most likely wind direction.
b. Sketch your predicted ash cloud coverage based upon the wind direction
and possible eruption magnitude.
11. List 2 precautions that could be taken to reduce fatalities and promote survival
during and after an eruption for each of the levels listed below:
Individual-
City (local)-
State-
National-
Name: ___________________
Date: ______________
West US Region
SUPER ZIT
How BIG are Volcanic Eruptions?
Every year about 60 volcanoes erupt, but most of the activity is pretty weak. How do
volcanologists measure how big an eruption is? There is not any single feature that
determines the "bigness", but the following eruption magnitude scale - called the
Volcanic Explosivity Index or VEI - is based on a number of things that can be
observed during an eruption. According to this scale, really huge eruptions don't happen
very often, luckily!
VEI Description
Plume
Height
Volume
Classification
How
often
Example
daily
Kilauea
0
nonexplosive
< 100 m 1000s m3
Hawaiian
1
gentle
1001000 m
10,000s m3
Haw/Strombolian daily
Stromboli
2
explosive
1-5 km
1,000,000s
m3
Strom/Vulcanian weekly
Galeras, 1992
3
severe
3-15 km
10,000,000s
m3
Vulcanian
yearly
Ruiz, 1985
4
cataclysmic
10-25
km
100,000,000s
Vulc/Plinian
m3
10's of
years
Galunggung,
1982
5
paroxysmal >25 km 1 km3
Plinian
100's of
years
St. Helens,
1981
6
colossal
>25 km 10s km3
Plin/Ultra-Plinian
100's of
years
Krakatau,
1883
7
supercolossal
>25 km 100s km3
Ultra-Plinian
1000's of Tambora,
years
1815
8
megacolossal
>25 km 1,000s km3
Ultra-Plinian
10,000's
of years
Yellowstone,
2 Ma
Displaced Material
90.0
80.0
Volume (cubic kilometers)
70.0
60.0
Tambora (1815)
Mazama (7600 BC)
Katmai (1912)
Kraktoa (1883)
St Helens (1900 BC)
Vesuvius (79)
Hekla (1104)
Fugi (1500)
St Helens (1980)
St. Helens (1707)
Pelee (1902)
50.0
40.0
30.0
20.0
10.0
0.0
1
Volcano
Human Fatalities
40,000
36,000
35,000
30,000
30,000
Fatalities
25,000
20,000
20,000
Series1
15,000
12,000
10,000
5,000
4,000
2,000
1,584
60
0
Krakatoa
(1883)
Mount
Mount Etna
Pelee (1902)
(1669)
Tambora
(1815)
Mount
Vesuvius
(1631)
Mount
Vesuvius
(AD 79)
Mount
Agung
(1963)
Mount St.
Helens
(1980)
Teacher Notes for Supervolcano Activity
This activity is based upon the docudrama titled “Supervolcano” which is available
on DVD from many sources. It is a wonderful addition to a volcano unit because is
provides a perspective on how the U.S. might be affected by an enormous eruption from
Yellowstone. It opens many discussions ranging from what is the probability of such an
eruption to how prepared are we for any eruption of substantial size.
Some prior preparation will be required to complete this activity. I generally run
this activity after completing a demonstration/activity which leads students to the
following conclusions:
• The higher the viscosity of the magma (determined to a large extent by the
silica content), the more difficult it is for gases to escape thereby leading
to the potential for a more explosive eruption.
• The higher the water content of the magma, the greater the gas pressure
creating a potential for a more explosive eruption.
It will also be necessary for students to have a working knowledge of textures of
extrusive rocks and the eruptive history they reflect. Along with this the terms “felsic”
and “mafic” need to have been covered. This portion can be presented as part of the
introduction to the activity. Using fine grained or porphyritic textured rocks, show that
rocks such rhyolite appear light colored due to the high quartz/feldspar content. Using
similar textured rocks, rocks such as basalt appear dark colored due to the high
iron/magnesium content (with a bit of help from dark colored feldspars). Having such
samples on hand or projecting images to the entire class via a data projector is helpful.
You will need to have either samples or images of tuff taken from the
Yellowstone area (there are many areas to the west of Yellowstone Park in Idaho that
have such samples for cost of a fun summer trip). Do realize that in the later stages of
previous Yellowstone Hotspot eruption episodes, late phase eruptions also created flows
of the much darker basalt.
I created packets of material for students to use while completing the activity
which consisted of the VEI index and the 2 bar graphs showing displaced material of
various volcanoes and human fatalities.
•
First, show the DVD. For a 47 min. class period, I allowed 3 days for viewing
and brief discussion
•
Second, show the power point presentation (here shown in pdf format). When
introducing the VEI Scale, emphasize that a number of characteristics of volcanic
eruptions were used in developing the scale. The displaced material graph
compares Mt. St. Helens with a number of historical volcanic eruptions and is
based upon estimates of materials displace. The human fatalities graph shows the
number of human fatalities with some of the eruptions shown in the displaced
materials graph. At the end of the activity, an assumption is made that a new
eruptive center appears in Montana and students are asked to make some
predictions. Realize that this is purely conjectural. Many factors will combine to
•
•
determine where and if the Yellowstone eruptive center will re-emerge some time
in the future. The hot spot may behave much differently as it encounters the core
of the Rockies. There is also the possibility that the hot spot could also disappear,
never to emerge again. I have included an image showing the historical track of
eruptions created as North America moved over the hot spot
(http://geodyn.ess.ucla.edu/~hernlund/ystrack-timing-web.jpg).
Third, complete the activity. Again, it is best if you have tuff samples from the
greater Yellowstone area to use with this lab. To introduce the activity, I used a
data projector to show various graphics used in the activity and the packet.
Overheads work fine as well.
Follow up the activity with a discussion centering upon the probability of such an
eruption occurring in their lifetime, how different a super eruption is from those
we are more familiar with, and how prepare we are on a local, national, and world
scale to deal with such an eruption.