Natural Hazards Classwork
Classwork #1
Name: __________________________
4th Grade PSI
The Alps are the highest mountain range in Europe. They span
eight different countries: Italy, Slovenia, Switzerland, Monaco,
Liechtenstein, Germany, France and Austria. In the winter of
1950-1951, the Alps experienced 649 avalanches that killed over
265 people and caused extensive damage. This was the only time
in history that this many avalanches hit the same area in such a
short amount of time. This three month period has been named
the Winter of Terror.
An avalanche occurs when snow flows quickly down a
mountainside. Avalanches can reach speeds of 80 mph within just
5 seconds! Avalanches occur when something causes the
snowpack to crumble. When this happens, an entire slab of
broken ice and snow will travel down a mountain as an
avalanche. Most avalanches occur when the load (or weight) on
top of the snow increases, causing the snowpack to break. The
load on the snowpack can increase for many reasons: skiers,
animals or even additional snowfall. Sometimes, gravity alone is
enough to trigger an avalanche. Earthquakes can also cause
snowpack to crumble into an avalanche.
The Winter of Terror is thought to have been caused by an
abnormal weather system. The Alps received high levels of
precipitation combined with a polar cold front. This combination of
factors caused the area to receive large amounts of snowfall in
just a 2-3 day period. The accumulation of snow was very heavy
and caused the snowpack to crumble, resulting in numerous
avalanches.
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4th Grade PSI
Natural Hazards
1. Describe two ways that an avalanche could be triggered.
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2. Wind is one factor that can cause an avalanche. Winter
winds can push surface snow in one direction, causing it to
pile up on top of snowpack. How could this trigger an
avalanche?
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3. Avalanches are most common in the 24 hours after a snow
storm that deposits 12 inches or more of snow. Explain this
statement.
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4th Grade PSI
Natural Hazards
Natural Hazards Homework
Homework #1
Name: __________________________
4th Grade PSI
As a natural hazard, avalanches cannot be prevented. The
damage caused by natural hazards, however, can be minimized.
One of the dangers leading to avalanches is increased weight on
top of the snowpack. The weight causes the snowpack to
suddenly break. One way to prevent sudden avalanches is to
trigger small avalanches when no people are around.
Researchers dig holes and analyze the layers of snowpack. When
they find a weak layer, they will trigger an avalanche by using
explosives. This decreases the stress on the snowpack and helps
to prevent future uncontrolled avalanches.
Another method is to use structures to minimize the risk of an
avalanche. A variety of different snow walls can be constructed to
change the way that snow accumulates. This helps to minimize
dangerous buildup of snow. Forests are a natural method of
changing the accumulation of snow. The trees in a forest also
slow down an avalanche, when one does form. In some cases,
snow walls are constructed to slow down avalanches and to
protect areas from damage.
You are the owner of a renowned ski resort. The highlight of your
resort is a steep ski slope that is incredibly challenging. Skiers
come from all around the world to ski this particular slope. When
you opened the resort, you clear cut the land of all trees in order
to provide the most amazing view possible to your customers.
It has come to your attention that the snowpack on the ski slope is
compromised in several locations. The ski lodge, parking lot and
main road are located at the bottom of the slope. If an avalanche
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4th Grade PSI
Natural Hazards
occurs, it will destroy all of your property as well as the lives of the
people who travel to your resort.
You have been urged to close the slope in order to address the
issue before a deadly avalanche occurs. You are meeting with the
authorities later in the week to present your avalanche
management plan. Write your plan below. Be sure to explain each
step of your plan.
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4th Grade PSI
Natural Hazards
Earthquakes Classwork
Classwork #2
Name: __________________________
4th Grade PSI
Label each fault and describe the type of movement that occurs.
1. Fault: ___________________
Movement:
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2. Fault: ___________________
Movement:
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3. Fault: ___________________
Movement:
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Source: USGS
4.
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4th Grade PSI
Natural Hazards
4. Your brother comes home and tells you that earthquakes
happen every time Earth’s plates move. Is he correct? Why
or why not?
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4th Grade PSI
Natural Hazards
Earthquakes Homework
Name: __________________________
Homework #2
4th Grade PSI
The chart below shows information from several earthquakes that
have occurred between 1906 and 2008. Look at the information
and then answer the questions that follow. “Magnitude” refers to
the rating of the earthquake on the Richter scale. “Rupture length”
refers to the length of the fault that moved.
Magnitude Date
9.1
7.9
7.9
7.8
7.3
7.3
7.0
7.0
6.8
6.7
6.4
5.9
5.4
Location
Rupture Length Duration
(kilometers)
(seconds)
December 26, 2004 Sumatra, Indonesia 1200
500
January 9, 1857
Fort Tejon, CA
360
130
May 12, 2008
Sichuan, China
300
120
April 18, 1906
San Francisco, CA
400
110
June 28, 1992
Landers, CA
70
24
August 17, 1959
Hebgen Lake, MT
44
12
October 17, 1989 Loma Prieta, CA
40
7
October 28, 1983 Borah Peak, ID
34
9
February 28, 2001 Nisqually, WA
20
6
January 17, 1994 Northridge, CA
14
7
March 10, 1933
Long Beach, CA
15
5
October 1, 1987
Whittier Narrows, CA 6
3
July 29, 2008
Chino Hills, CA
5
1
Source: Earthquakecountry.org
1. What earthquake had the largest rupture length? What was
the magnitude of this earthquake? How long did the
earthquake last?
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4th Grade PSI
Natural Hazards
2. What earthquake had the smallest rupture length? What was
the magnitude of this earthquake? How long did the
earthquake last?
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3. Based on this information, how does rupture length relate to
the magnitude of an earthquake? (Hint: As the rupture length
of an earthquake increases, what happens to the
magnitude?)
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4. Based on this information, how does the rupture length
relate to the duration of an earthquake? (Hint: As the rupture
length of an earthquake increases, what happens to the
duration?)
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4th Grade PSI
Natural Hazards
Volcanoes Classwork
Classwork #3
Name: __________________________
4th Grade PSI
Categorize the following volcanoes as active, dormant or extinct.
1. ____________________Mount Etna in Italy has been
erupting continuously for the past
3,500 years.
2. ____________________Meiji is the oldest island in the
Hawaiian Islands. It is 85 million
years old and no longer has a
magma source.
3. ____________________Mount Kilimanjaro in Tanzania has
not erupted in hundreds of
thousands of years; however, there
is still an active magma source
running underneath the volcano.
The statements below describe different ways that a volcano can
form. Categorize each as convergent boundary, divergent
boundary or hotspot.
4. ____________________Sometimes, magma pushes to the
surface in areas not located by
plate boundaries.
5. ____________________On the bottom of the ocean, some
plates move apart from each other.
Magma rises to the surface to
create volcanoes.
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4th Grade PSI
Natural Hazards
6. ____________________When two plates collide, one plate
pushes beneath the other. As the
lower plate melts, magma
sometimes rises to the surface and
forms a volcano.
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4th Grade PSI
Natural Hazards
Volcanoes Homework
Homework #3
Name: __________________________
4th Grade PSI
You are the newly elected mayor of Volcanoville, a small town
that sits at the base of a large volcano. Your first task is to
establish a Volcano Monitoring Program. You understand the
risks of living directly beside a volcano. Although you cannot
prevent the volcano from erupting, you want to be able to
minimize casualties if it ever erupts in the future. Explain the steps
of your monitoring program below. How is each step beneficial?
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4th Grade PSI
Natural Hazards
Tsunamis Classwork
Classwork #4
Name: __________________________
4th Grade PSI
1. Tsunamis are large ocean waves that can reach up to 30
meters high. Describe how tsunamis are linked to
earthquakes.
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2. What are two other ways that tsunamis can be created?
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4th Grade PSI
Natural Hazards
3. The picture below shows the DART buoy system. Describe
the function of each labelled part.
3
2
1
1
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3
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4th Grade PSI
Natural Hazards
Tsunamis Homework
Homework #4
Name: __________________________
4th Grade PSI
How Tsunami Science Has Advanced Since 2004 Tragedy
The Indian Ocean tsunami of Dec. 26, 2004, was one of the worst
natural disasters in history, killing 243,000 people in South Asia
and East Africa with little to no warning. Ten years later,
expanded networks of seismic monitors and ocean buoys are on
the alert for the next killer wave.
But hurdles remain in saving lives of everyone facing a tsunami
threat. In 2004, tsunami waves approached coastal Indonesia just
nine minutes after the massive magnitude-9.1 earthquake
stopped shaking, said Mike Angove, head of the National Oceanic
and Atmospheric Administration's tsunami program.
Even today's expanded monitoring network can't issue an alert
that quickly, "so we have to prepare the public to interpret the
signs and survive," Angove said.
When a tsunami wave rises, the alert comes from a $450 million
warning network that was put in place after 2004's catastrophe.
The Indian Ocean Tsunami Warning System includes more than
140 seismometers, about 100 sea-level gauges and several
buoys that detect tsunamis.
The global network of Deep-Ocean Assessment and Reporting of
Tsunami buoys, which detects passing tsunami waves, has also
expanded, from six DART buoys in 2004 to 60 buoys in 2014,
Angove said.
Getting the warnings to people living in remote coastal areas is
one of the biggest hurdles for the new system. Another hurdle has
to do with forecasting the effect of reflected tsunami waves. The
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4th Grade PSI
Natural Hazards
2004 Indian Ocean tsunami ricocheted off island chains, and
some of the worst flooding arrived unexpectedly late in places like
Sri Lanka and Western Australia.
After an earthquake, scientists at NOAA's tsunami warning
centers spend about an hour working out the details of a tsunami
forecast, said Vasily Titov, director of NOAA's Center for Tsunami
Research. The results project when the wave will arrive at
shorelines and harbors, estimate tsunami-induced currents and
gauge the height of the waves.
The agency's goal is to dramatically reduce that hour of lag time.
"We're now at the point where we want to do it in five minutes,"
Titov said. That means building out the seismic network, getting a
faster response from sea-level sensors and speeding up the
computer forecasts.
"When these three components come together, then we can save
everybody," Titov said.
— Becky Oskin, LiveScience
Source:
NBC News 2014, How Tsunami Science Has Advanced Since 2004 Tragedy, article,
viewed on 30 June 2015, <http://www.nbcnews.com/science/environment/howtsunami-science-has-advanced-2004-tragedy-n275221>.
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4th Grade PSI
Natural Hazards
1. How have tsunami warning systems improved since the
2004 tsunami?
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2. What is a weakness in current tsunami warning systems?
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3. How long does it take scientists to interpret data to form a
tsunami forecast?
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4. What three things must become better in order to decrease
the time it takes to form a tsunami forecast?
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4th Grade PSI
Natural Hazards
Answer Key
Natural Hazards Classwork
Classwork #1
1. Answers will vary but may include: increased load by skiers, animals or snowfall,
explosives, gravity, or earthquakes.
2. When wind pushes snow to accumulate in one area, this increased weight can
cause the snowpack to crumble. This can trigger an avalanche.
3. When there is a large accumulation of snow, the increased weight can cause the
snowpack to crumble, triggering an avalanche. This is why avalanche danger is
high in the 24 hours after a large snow storm.
Natural Hazards Homework
Homework #1
Answers will vary. Samples ideas: Plant trees to create forest surrounding the ski
slope. This will help snow not to accumulate in one place and will slow down an
avalanche if one does occur. Shut down the resort and use explosives to relieve
stress in the snowpack. Create snow walls around the barriers of the ski slope to
slow down an avalanche and to protect surrounding areas.
Earthquakes Classwork
Classwork #2
1. Strike-slip. Two rocks slip horizontally past each other.
2. Normal. One rock moves downwards.
3. Thrust. One rock moves upwards.
4. Your brother is wrong. Earth’s plates are constantly in motion. Earthquakes occur
when plates stop moving, store up energy and then suddenly release that
energy.
Earthquakes Homework
Homework #2
1. The largest rupture length was Sumatra, Indonesia. The magnitude was 9.1 and
the duration was 500 seconds.
2. The smallest rupture length was Chino Hills, CA. The magnitude was 5.4 and the
duration was 1 second.
3. As rupture length increases, the magnitude increases.
4. As rupture length increases, the duration increases.
Volcanoes Classwork
Classwork #3
1. Active
2. Extinct
3. Dormant
4. Hot spot
5. Divergent boundary
6. Convergent boundary
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4th Grade PSI
Natural Hazards
Volcanoes Homework
Homework #3
Answers will vary but should include seismic monitoring, gas monitoring and
ground deformation monitoring.
Tsunamis Classwork
Classwork #4
1. When an underwater thrust earthquake forces a tectonic plate to move upwards,
the column of water above the plate also is pushed upwards. This creates a
wave (tsunami) that radiates out in all directions.
2. Tsunamis can also be created from underwater landslides or volcanoes.
3. 1 – This device detects seismic activity on the ocean floor.
2 – This device detects changes in sea height.
3 – This satellite receives signals from the other components and send the
information to scientists.
Tsunamis Homework
Homework #4
1. In 2004, there were only 6 DART buoys. As of 2014, there were 60.
2. It takes scientists a long time to create a tsunami forecast. Sometimes, it takes
longer to form the forecast than for the tsunami to hit land.
3. 1 hour
4. Scientists was to increase the seismic network (increase DART sensors), get a
faster response from the sea-level sensors and make computer forecasts run
quicker.
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4th Grade PSI
Natural Hazards