Natural Disasters Study Guide
Helpful Hints:
This study guide will focus on natural disasters. The Eco-Meet test may consist of multiple
choice, true/false, fill in the blank, matching, identification, label a diagram, or short answer.
Anything in this study guide has the potential to be on the test. Pay close attention to words in
bold, diagrams, charts, and identification.
A natural disaster is an environmental event caused by forces of nature. The severity of a
disaster is measured in lives lost, effect on the economy, physical damage, and the ability of the
population to rebuild.
Heat Related Nature Disasters:
What are heat related natural disasters?
A heat wave is an extended period of time (from several days to weeks) of unusually high
temperatures. A heat wave takes a physical toll on people and animals. It may cause a drought,
and the environment suffers.
A drought is a lengthy period of time (months or even years)
land has had a decrease in water supply. A drought can cause:

many farms to loose crops.
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a water shortage. During a drought, people may have
Figure 1: The Dust Bowl of the 1930's was a series of
dust storms over several years.
to make changes to their lifestyle, such as not
watering their lawn.
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huge clouds of dust instead of rain, known as Dust Storms.
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wildfires. Dry underbrush is ideal for fueling wildfires, large destructive fires that spread
quickly over natural areas.
How does a heat wave form?
Air sinks towards the surface under high pressure conditions and then acts as a cap holding in
hot air. The buildup of heat on the surface then becomes a heat wave. Because the air cannot
lift, cumulus clouds are less likely to form, making rain unlikely and a drought possible.
Heat related safety tips:
Being prepared:
 Have a disaster plan including evacuation routes and area shelters.
 Have an emergency kit with blankets, flashlights, batteries, non-perishable food, can
opener, bottled water, waterproof matches, shovel, windshield scraper, tool kit, jumper
cables, a water container, protective clothing, gasoline, road maps, flares, first aid kit,
instructions how to turn off utilities, a list of emergency numbers, and a battery
operated radio.
During a heat related natural disaster:
 Know the signs of heat exhaustion, which shows itself in symptoms such as vomiting,
diarrhea, headache, dehydration, nausea, etc.
 During a heat wave, people should limit their time outdoors and drink plenty of fluids.
 Do not travel unless evacuation is necessary or in the event of an emergency.
 During a wildfire, watch for changes in the speed and direction of fire and smoke.
 During a drought, do your best to conserve water.
Heat related natural disasters to remember:
HEAT WAVE: The heat wave in July 1995 was one of the most
notorious in Illinois with temperatures hitting 106 Fahrenheit. The
heat index, which factors in temperature with humidity for an
estimate of how hot it feels, was above 120 Fahrenheit. The
temperatures were so hot; train rails melted and became warped.
Within a week 1,000 people had already lost their lives. Illinois is
much more prepared with more cooling centers and a system for
conducting wellness checks.
Figure 2: California lake in 2010 (left) Same
California lake in 2015 (right)
WILDFIRES: During the week of October 8-14, five of the worst fires in U.S. history all broke out
in the same week across the Great Lake region, including the Great Chicago Fire. The five fires
were caused by prolonged and widespread drought, high temperatures, and ignition by
lightning strikes.
DROUGHT: California is currently entering its fourth year of a record-breaking drought and in a
state of emergency. Officials are asking residents to reduce their water use by 35%! According
to an aerial survey conducted in April 2015 by the U.S. Forest Service, about 12 million trees
have died in California because of extreme drought. The extreme drought conditions are
making California high risk for wildfires. As of August 3, 2015, California firefighters were
actively fighting 14 wildfires throughout the state.
Avalanches:
Figure 3: The circled area shows where the avalanche has released from a
stable snow area.
What is an Avalanche?
An avalanche is the quick flow of snow down a slope
because it has become too heavy. The further the avalanche
gets down the slope, the faster it moves. As the avalanches
moves downhill the force is strong enough to pick up ice, rocks, and trees. Avalanches are
common in mountainous terrain and are not possible in Illinois.
How does an avalanche form?
Natural factors that cause avalanches include heavy snowfall, melting snow, precipitation,
falling rocks or earthquakes. Humans may accidently cause avalanches with recreational
activities such as skiing or snowmobiling.
Are there different types of avalanches?
A Slab avalanche is formed when a huge
area of snow separates from its base. A
slab avalanche varies in thickness and
causes 90 percent of avalanche related
deaths.
A Loose snow avalanche is common in
steep terrains. It usually occurs in snow that has just fallen. They resemble a teardrop with a
Figure 4: The difference between a slab avalanche and a loose snow
single starting point.
avalanche.
Avalanche safety tips:
Being Prepared:
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
Government organizations issue daily avalanche warnings with weather forecasts.
www.avalanche.org provides a lot of information and provides a list of current warnings.
Wear appropriate gear like a safety signal, air supply, and a snow buoy. There are also
special backpacks that inflate in the event of an avalanche.

Play it Safe. Cross snow slopes one person at a time and don't travel above your partner.
See diagram on the next page about how to travel across snow covered sloped terrain.
Safest Route to Cross
Potential
Avalanche Path
NEVER
Figure 5: This shows the correct route to cross on snow covered slopes.
During an avalanche:
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Move sideways from the avalanche. The center of an avalanche is where the snow
moves the fastest, making it the most dangerous place to be.
Try grabbing onto a tree or rock or staying afloat by swimming as hard as you can.
Create a small thirty minute air pocket by cupping your mouth.
Inflate your backpack and/or turn on your safety signal/beacon.
An avalanche to remember:
On May 31, 1970, an earthquake off the coast of Peru caused a section of Mt. Huascaran to
collapse. The avalanche moved downhill at a speed of 100 mph and ran nearly 11 miles. This
avalanche caused a lot of damage and an estimated 20,000 people lost their lives.
The worst avalanche in the United States was the
Wellington Avalanche of March 1, 1910, near
Stevens Pass, Washington. After several days of
blizzard-like conditions, the weather turned to
rain. As a result of lightning strikes, a slab of snow
broke loose from the side of Windy Mountain. A
ten-foot high mass of snow, half a mile long and a
quarter of a mile wide, fell toward the town,
killing 96 people.
Figure 6: The Wellington avalanche wiped out a stranded train.
Blizzards:
What is a blizzard?
A blizzard is a long-lasting severe snowstorm. In order to
qualify as a blizzard, winds must be at least 35mph and last at
least three hours. The amount of snowfall has little to do with
a storm qualifying as a blizzard.
Figure 7: Near zero visibility makes it very difficult
to see ahead of you.
Blizzards make travel very difficult as visibility is drastically reduced. If you cannot see more
than 9 feet in front of you, meteorologists use the term zero
visibility. A meteorologist is someone who studies the
science dealing with the atmosphere and its phenomena,
including weather and climate.
How does a blizzard form?
Jet streams are like rivers of wind high above us in the
atmosphere. These strips of strong winds can push air masses
around and affect weather patterns. Blizzards form when
the jet stream pushes very far south. This causes cold air
from the north to collide with warm air from the south.
Figure 8: Look how two jet streams dipped low into
the south and merged. Question: What area do you
think was hit with the blizzard? Answer: The east
coast, from Florida (which received 6 inches of
snow) all the way up to New York (which received
30 inches of snow) and beyond.
Are there different types of blizzards?
Severe blizzard: Winds over 45mph, temperatures at 10
degrees Fahrenheit or lower, near zero visibility.
Ground blizzard: No new snow is falling, but snow already on the
ground is blown around by winds creating near zero visibility
conditions.
Figure 9: Chicago, IL after the blizzard of
2011. Photo courtesy of CBS.
Blizzard safety tips:
Being prepared:
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
Have a disaster plan including evacuation routes and area shelters.
Have an emergency kit with blankets, flashlights, batteries, non-perishable food, can
opener, bottled water, waterproof matches, shovel, windshield scraper, tool kit, jumper
cables, a water container, protective clothing, gasoline, road maps, flares, first aid kit,
instructions how to turn off utilities, a list of emergency numbers, and a battery
operated radio.
During a blizzard:
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Stay inside.
Close off unneeded rooms and windows to save heat.
Wear layers of loose-fitting, light-weight warm clothing.
Do not travel unless evacuation is necessary or in the event of an emergency.
An blizzard to remember:
Snow in Iran? The Iran Blizzard of 1972 is the
deadliest recorded blizzard; approximately
4,000 people died. Whole villages were
completely buried beneath 10 feet to 26 feet
of snow!
The Great Blizzard of 1888 was a nor’easter,
killing 400 people after dumping 4 feet of
snow on the east coast of the United States.
A nor’easter gets its name from the direction
of oncoming winds. Early warning systems
and technology to make weather predictions
have come a long way but being prepared is
still critical in emergency situations.
Figure 10: Picture from the 1972 Iran Blizzard.
Thunderstorms:
What is a thunderstorm?
A thunderstorm is characterized by lightning and thunder as well as strong winds and rains if
cumulonimbus clouds are present in the sky. Cumulonimbus clouds are dense clouds that reach
huge heights of almost 12 miles tall in the sky.
How do thunderstorms form?
A thunderstorm can be created because of a sudden surge of warm and moist air. As the warm
and moist air moves upwards, it will cool down and thicken, creating cumulonimbus clouds.
Once air inside the cloud reaches a certain temperature, ice and water droplets form and start
falling towards Earth. As they fall, droplets began sticking together creating large raindrops.
This falling rain creates a new downdraft of air, causing the strong winds associated with a
thunderstorm.
Are there types of thunderstorms?
A single-cell thunderstorm is a small and quick storm that grows and dissipates within an hour.
A multi-cell storm is a group of individual thunderstorms that move together as a large system.
Individual cells usually last under an hour, while the system as a whole may last for several
hours.
A squall line is a group of storms arranged in a line, often accompanied by high wind and heavy
rain, but passing quickly. They can be hundreds of miles long but are typically less than 20 miles
wide. See picture, to the right, of a squall line.
A supercell is a long-lived (greater than 1 hour) and highly
organized storm feeding off an updraft (a rising current of air)
that is rotating. This rotating updraft can be 10 miles in diameter
and up to 50,000 feet tall. Most large and violent tornadoes
spawn from supercells as well as hail. Hail is frozen precipitation
with a diameter greater than 5mm. In 2014, Illinois was ranked
2nd at having the worst hail damage with 43,821 hail related
claims. Check out the tennis ball size hail that hit Tuscola, IL in
May of 2014.
Thunderstorm safety tips:
Being prepared:
 Know the difference between a thunderstorm watch and warning. A Thunderstorm
Watch means a thunderstorm is possible for your area. A Thunderstorm Warning
means a thunderstorm is taking place in your area – take shelter immediately.
 Have a disaster plan including evacuation routes and area shelters. Know the safe room
in your house (typically a room without windows) such as a basement, bathroom or
closet.
 Have an emergency kit with blankets, flashlights, batteries, non-perishable food, can
opener, bottled water, waterproof matches, shovel, windshield scraper, tool kit, jumper
cables, a water container, protective clothing, gasoline, road maps, flares, first aid kit,
instructions how to turn off utilities, a list of emergency numbers, and a battery
operated radio.
During a thunderstorm:
If you’re outdoors:
 Keep an eye on the sky. Look for darkening skies, flashes of lightning, or increasing
winds. If you see or hear any of these take shelter immediately.
 To avoid lightning strikes: stay away from trees and crouch down in an open area with
your feet together. Avoid water and metal. If you are with a group of people stay at
least 15 feet away from each other. If someone is struck by lightning call 9-1-1 or send
for help immediately. It is okay to touch someone who has been struck by lightning.
 Wait at least 30 minutes after the last observed lightning strike or thunder to return
outdoors.
If you’re indoors:
 Avoid water. It’s a great conductor of electricity, so do not take a shower, wash your
hands, wash dishes or do laundry.
 Do not use electric equipment like computers and appliances during a storm.
Stay away from windows and doors.
A thunderstorms to remember:
Thunderstorms occur so frequently, but in 2009 a derecho hit southern Illinois. A derecho
("deh-REY-cho") is a widespread, long lasting, rapidly moving band of storms. The May 8, 2009
"Super Derecho" was one of the most intense and unusual derechos ever observed. Derechos
are nicknamed “inland hurricanes.” Imagine a microburst that lasts much longer than a couple
minutes. A derecho is defined by s storm front that extends for more than 250 miles and
include sustaining wind gusts of at least 58 mph.
Tornadoes:
What is a tornado?
Tornadoes, twisters, or cyclones are destructive columns of air that rotate and have contact
between the ground and a cumulonimbus cloud. Tornadoes tend to come in many different
shapes and sizes, but most of the time they look like a funnel with a narrow end that touches
the Earth’s surface and gets wider at the top. Containing mostly debris and dust, tornadoes
usually have high wind speeds and travel a few miles before they deplete.
A funnel cloud is a rotating cone-shaped column of air extending down from a thunderstorm
cloud, but not actually touching the ground. Once it reaches the ground it is called a tornado.
Cold air
How does a tornado form?
Most tornadoes form from
thunderstorms when warm, moist air
from the Gulf of Mexico and cool, dry
air from Canada mix.
Rain
Warm air
A) When these two air masses meet, they create instability in the atmosphere. B) Rising air tilts
the rotating air from horizontal to vertical. An area of rotation extends through much of the
storm. C) Most strong and violent tornadoes form within this area of rotation.
Are there different types of tornadoes?
A waterspout is a tornado that forms over water.
A microburst is a concentrated downdraft of sinking air that can cause serious wind damage. A
microburst occurs inside a thunderstorm with rain, thunder and lightning but when the air sinks
to the ground straight line winds occur. Check out this quick video of a microburst:
https://www.youtube.com/watch?v=kLzbJ5XQEQ8. Can you tell when the burst hits? Please view
this video of a meteorologist from Maine who explains the difference between a tornado and a
microburst. https://www.youtube.com/watch?v=kKc9Bo3qN0w.
Land tornadoes have different characteristics based on their size and strength. A tornado lower
on the Fujita scale cause minimal damage while an EF-5 can cause complete devastation.
Figure 11: This tornado was an EF-5 and about a mile wide! It hit Joplin,
Missouri in 2011.
Tornado safety tips:
Being prepared:
 Know the difference between a tornado watch and warning. Tornado Watch Tornadoes are possible in and near the watch area. Review and discuss your emergency
plans, and check supplies. Be ready to act quickly. Tornado Warning - A tornado has
been sighted or indicated by weather radar. Tornado warnings indicate imminent
danger to life and property.
 Have a disaster plan including evacuation routes and area shelters.
 Have an emergency kit with blankets, flashlights, batteries, non-perishable food, can
opener, bottled water, waterproof matches, shovel, windshield scraper, tool kit, jumper
cables, a water container, protective clothing, gasoline, road maps, flares, first aid kit,
instructions how to turn off utilities, a list of emergency numbers, and a battery
operated radio.
During a tornado:
 Go immediately underground to a basement or cellar. If an underground room is
unavailable, go to an interior room like a closet or bathroom.
 Evacuate from cars, apartments and mobile homes to a community shelter.
 Cover your head from falling debris with pillows, blankets or a mattress.
 If caught outside, lie low on the ground and wait for the storm to pass.
 Do not travel unless evacuation is necessary.
A tornado to remember:
Illinois has endured many tornados but the tornado on May 26, 1917, that hit the Mattoon and
Charleston area was a record breaker. This EF-4 was once believed to be a single tornado with a
path 293 miles long, but it was later determined to be multiple tornadoes. The most damage
occurred in the Mattoon/Charleston area with damage costs over 1 million dollars.
Hurricanes:
What is a hurricane?
Hurricanes can be described as giant, swirling tropical storms that occur in the ocean. These
monster storms can reach wind speeds up to 160 mph. They can also unleash a whopping 2.4
trillion gallons of rain a day. Hurricanes occur in the Caribbean Sea, Eastern Pacific Ocean,
Southern Atlantic Ocean and in the Gulf of Mexico. The Atlantic hurricane season starts in the
month of June and ends in November.
How do hurricanes form?
Hurricanes start off in the warm ocean waters as tropical depressions. The temperature of
these waters would be around 80 degrees Fahrenheit. A tropical depression may strengthen
into a tropical storm. A tropical storm is a group of heavy thunderstorms with circulation and
constant winds between 39 – 74 mph but no eye is present yet. When a storm out in the ocean
reaches wind speeds of at least 74 miles an hour, it becomes a hurricane.
The low pressure center which the hurricane spins around is known as
the ‘eye.’ Sinking air makes this 20 to 30-mile-wide area notoriously calm
but the area around the eye wall is where the wind is the strongest.
Are there different types of hurricanes?
When a storm out in the ocean reaches
wind speeds of at least 74 miles an
hour, it becomes a hurricane and earns
a category rating of 1 to 5 on the SaffirSimpson Scale. The scale is used to
measure the strength and intensity of a
hurricane depending on its wind speed.
Figure 12: This diagram shows the different categories based on the storm’s wind speed
and the possible water surge it can cause on the coast.
Hurricane safety tips:
Being Prepared:
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Knowing a watch from a warning. A Hurricane Watch indicates an area could experience
hurricane conditions within 36 hours. Individuals should start taking protective
measures like boarding up doors and windows, buying emergency supplies and
evacuating if necessary. A Hurricane Warning indicates that sustained winds of at least
74 mph are expected within 24 hours.
Have a disaster plan including evacuation routes and area shelters.
Have an emergency kit with blankets, flashlights, batteries, non-perishable food, can
opener, bottled water, waterproof matches, shovel, windshield scraper, tool kit, jumper
cables, a water container, protective clothing, gasoline, road maps, flares, first aid kit,
instructions how to turn off utilities, a list of emergency numbers, and a battery
operated radio.
DURING A HURRICANE:
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Stay away from low-lying and flood prone areas. If your home isn’t on higher ground,
evacuate.
Always stay indoors during a hurricane.
Do not travel unless evacuation is necessary or in the event of an emergency.
Board up windows and bring in outdoor objects prior to the storm hitting.
A hurricane to remember:
The Hurricane of 1900 made landfall in Galveston, Texas with 145 mph winds, making it
a Category 4 storm on the Saffir–Simpson Scale. Storm surges were in excess of 15 feet and it is
estimated that 8,000 people lost their lives, 3600 buildings were destroyed, and damage
estimates exceeded $20 million (that would be around $700 million today).
There was no sign of an approaching hurricane, but Galveston Weather Station Chief Isaac M.
Cline ordered hurricane warning flags to be flown. Early the next morning, Cline warned every
one of the storm – advising them to get to higher ground immediately. At the time, the highest
point in the city was only 8.7 feet above sea level. By midmorning, rain clouds began rolling in
and at the height of the storm, swells were as high as 15 feet high.
Today the sea wall is 17 feet high and stretches across 10 miles of coastline. This is a perfect
example on how people have no control over the weather, but by making necessary
preparations they can limit the amount of destruction.
Floods:
Figure 13: Flooding in Illinois.
What is a flood?
A flood is land covered by water that is not usually covered by water. This means that any time
a river, lake, or other body of water overflows its banks, it’s flooding.
A crest is the highest level of a flood.
How does flooding form?

Heavy rainfall: Flooding from rainfall generally happens when more rain falls than the
soil, rivers, and streams can absorb. When rivers and streams can no longer hold water,
they start to flood their banks.
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Melting snow and ice: When spring rains arrive at the same time snow is melting the
ground is too moist to hold more water will often result in area flooding of rivers and
streams.
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Destruction: A tsunami or levee break can cause huge amounts of water to come
rushing down onto the plains.
Flood safety tips:
Being prepared:
 Know the difference between a Flood Watch and Flood Warning. A Flood Watch is when
conditions are favorable for flooding due to ground saturation. A Flood Warning means
flooding is occurring in the designated area.
 Have a disaster plan including evacuation routes and area shelters.
 Have an emergency kit with blankets, flashlights, batteries, non-perishable food, can
opener, bottled water, waterproof matches, shovel, windshield scraper, tool kit, jumper
cables, a water container, protective clothing, gasoline, road maps, flares, first aid kit,
instructions how to turn off utilities, a list of emergency numbers, and a battery
operated radio.
During a flood:
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If you find yourself under a flood warning, make sure to pay attention to radio or television
warnings for updates.
Turn off utilities at the main switches and disconnect electrical
appliances.
Do not travel unless evacuation is necessary or in the event of an
emergency. It is easy to underestimate the power of moving
water. Six inches of moving water can cause you to lose your
balance and fall.
Do not drive through flood water.
Stay inside.
Figure 14: An example of a
sandbag levee.
A flood to remember:
In 1993, the Mississippi River and adjoining rivers swelled past their banks due to heavy rainfall.
Watch this video at minute 2:50 of an Illinois farm vs. a flooding river.
https://www.youtube.com/watch?v=N5avsx-8xJo. What caused the river to flood into the
farm? The Great Flood of 1993 cost $20 billion dollars in damage. Residents up and down the
river used 75 million sandbags to create levees to fight the flooding. Levees are temporary walls
to prevent flooding.
Figure 15: The top picture shows the Mississippi at its normal water levels. The bottom picture shows
the expansive flooding that occurred in 1993.
Earthquakes:
What is an earthquake?
Fault
An earthquake is the sudden and violent movement of the
Earth’s crust and the series of vibrations that follow.
Earth’s crust: This is the solid thin layer of broken rocky plates
that covers the outside of the earth.
Figure 16: A disgram of an earthquake.
Plate: A plate is a section of the earth’s crust. Plates slide along or beside each other causing
friction and pressure. An earthquake occurs when a plate slips. There are about 17 plates on
the surface of the earth.
Fault: A break in the earth’s crust as a result of an earthquake.
Epicenter: The source of the earthquake on the earth’s surface.
Figure 17: A seismograph.
Focus: The source of the earthquake underground.
Seismograph: An instrument that measures and
records the force, duration and other details of an
earthquake. (See image on right)
Seismic waves: These waves are the vibrations and
movement that travel from the epicenter. The
vibrations of these waves are what cause the most
destruction during the earthquakes.
Magnitude: The amount of energy released during
an earthquake. The stronger the seismic waves on
the Richter Scale, the larger the magnitude.
Richter Scale: A measurement of an earthquake's
intensity. Each one-point increase on the scale
indicates ten times the amount of shaking and 33 times the amount of energy.
How is an earthquake formed?
The Earth’s crust is broken up into many rocky plates, like pieces of a puzzle, and rests on the
Earth’s mantle. These plates are constantly moving because of the mantle’s molten lava. As the
plates move past each other they sometimes get caught on each other and pressure builds up.
When the plates finally slip, energy is released as seismic waves, causing the ground to shake.
Earthquake safety tips:
Being Prepared:
 Have a disaster plan including evacuation routes and area shelters.
 Have an emergency kit with blankets, flashlights, batteries, non-perishable food, can
opener, bottled water, waterproof matches, shovel, windshield scraper, tool kit, jumper
cables, a water container, protective clothing, gasoline, road maps, flares, first aid kit,
instructions how to turn off utilities, a list of emergency numbers, and a battery
operated radio.
During an Earthquake:
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Drop down and take cover under furniture. Stay away from windows, bookcases or
furniture that can fall on you.
Stay indoors until the shaking stops. Be careful of aftershocks, smaller earthquakes that
occur after a large earthquake.
If you are outdoors, find a clear spot and drop to the ground.
If you are in a car, stay in the car until the shaking stops.
Do not travel unless evacuation is necessary.
An earthquake to remember:
President James Madison felt the New Madrid (Illinois) earthquake in the White House. Church
bells rang in Boston, Massachusetts, as well as the Liberty Bell in Philadelphia, Pennsylvania.
Three of the New Madrid earthquakes are on the list for the strongest and most damaging
earthquakes: the first one on December 16, 1811, a magnitude of 8.1 on the Richter scale; the
second on January 23, 1812, at 7.8; and the third on February 7, 1812, at 8.8. Boatmen
reported that the Mississippi River actually ran backwards for several hours. The earthquakes
destroyed thousands of acres of forest, and created two temporary waterfalls in the Mississippi
River.
Tsunamis:
What is a tsunami?
A tsunami is a series of gigantic ocean waves that cause a surge of water onto land. The surge
can reach heights up to 100 feet. The massive height of the water surge can lead to devastating
flood effects when it crashes over land. Almost 80 percent of tsunamis occur within the Pacific
Ocean’s ‘Ring of Fire’. This is due to the amount of earthquake and volcanic activity in the area.
How does a tsunami form?
Most tsunamis are formed from
earthquakes. An earthquake is the sudden
and violent movement of the earth’s crust
on a fault and the series of vibrations that
follow. When the pressure of the tectonic
plate at the ocean floor releases, it causes
the water above it to move in upward
waves. These rolling waves build up and
turn into one large wave - a tsunami.
Figure 18: A diagram of how an earthquakes causes tsuanmi
waves.
Tsunamis can reach speeds of 500 miles per
hour, racing across the ocean. That is about as fast as a jet plane! Tsunamis can travel the entire
length of the Pacific Ocean in less than a day. When tsunamis begin to form, they only appear a
foot high in the ocean. This makes them impossible to distinguish from regular tidal waves.
AS the waves get closer to the shoreline, their
energy and height grow drastically. The wave
sucks the water along the coast backwards into
the sea leaving the sea floor exposed. This is
called drawback. From land, this is the first
visual sign a tsunami is about to hit.
Water should be covering these rocks
Figure 19: Can you tell where the ocean water should be? This
is drawback for an impending tsunami.
Tsunami safety tips:
Be Prepared:
 When in coastal areas, stay alert for tsunami and earthquake warnings.
 Know the warning signs of a tsunami: rapidly rising or falling coastal waters
and rumblings of an offshore earthquake.
 Have a disaster plan including evacuation routes and area shelters.
 Have an emergency kit with blankets, flashlights, batteries, non-perishable food, can
opener, bottled water, waterproof matches, shovel, windshield scraper, tool kit, jumper
cables, a water container, protective clothing, gasoline, road maps, flares, first aid kit,
instructions how to turn off utilities, a list of emergency numbers, and a battery
operated radio.
During a tsunami:
 If a tsunami warning has been issued, evacuate immediately. Get to higher ground and
as far inland as you can.
 When a tsunami hits, be prepared for repeat waves.
A tsunami to remember:
The December 2004 Indian Ocean
tsunami was triggered by a 9.1
earthquake off the coast of Sumatra,
Indonesia. The earthquake triggered a
series of devastating tsunamis along
the coasts killing 230,000 people in 14
countries, and damaging coastlines
with waves 100 feet high. Indonesia
was the hardest-hit country, followed
by Sri Lanka, India, and Thailand.
Figure 20: 2004 Indian Ocean Tsunami
Landslides:
What is a landslide?
A landslide is when gravity forces debris and rocks to fall or
slide down a slope.
How does a landslide form?
Dirt and debris on a slope constantly fight gravity to stay in place. In the diagram above, you
can see where a section of the ground gave way from its original position and began sliding
downhill.
There are several reasons why a mass can give way from the slope. First heavy rains can change
the soil structure, cause erosion and destabilize the slope. Earthquakes can also cause a change
in the slope, making it unstable. Finally, the force of a volcanic eruption can cause the slope to
become unstable.
Are there different types of landslides?
Slide: a section of land breaks free from the slope, sliding downhill.
Creep: slow downhill movement of soil. Notice the fence post is starting to lean to the left. This
tells us the soil is slowly moving downward, pushing up against the fence.
Slump: The hillside gives way, sinking into the ground.
Torrent: landside due to heavy rains
Landslide safety tips:
Being Prepared:
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Landslides generally happen in areas where they have occurred in the past. Learn about
your area’s landslide risk.
Avoid doing projects that could decrease soil stability. For example: digging a hole on a
slope or building at the top or the base of a slope.
Have a disaster plan including evacuation routes and area shelters.
Have an emergency kit with blankets, flashlights, batteries, non-perishable food, can
opener, bottled water, waterproof matches, shovel, windshield scraper, tool kit, jumper
cables, a water container, protective clothing, gasoline, road maps, flares, first aid kit,
instructions how to turn off utilities, a list of emergency numbers, and a battery
operated radio.
During a landslide:
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If indoors - take refuge in the part of the building opposite the landslide.
If you are outdoors - quickly move away from the path of the landslide and stay far away
from river banks, trees, electrical wires and utility poles.
A landslide to remember:
Landslides have occurred in southern Illinois along river banks, but one of the worst landslides
on record occurred in 1920 in Kansu, China. An earthquake triggered massive landslides of dry,
rocky mountainsides and loess banks. Loess is a fine, powder mixture of silt and clay that is very
susceptible to slides and mudflows. When the landslides were triggered, many of the banks,
cliffside dwellings and hundreds of small villages fell into valleys below. Over 180,000 people
lost their lives.
Volcanoes:
What is a volcano?
A volcano is a rupture on the Earth’s crust that allows hot lava, volcanic ash, and gases to escape from a
magma chamber below the surface. There are more than 1500 active volcanoes on Earth today.
Magma: Liquid rock trapped in the volcano. Once the magma flows out of a volcano, it is classified as
lava.
Lava: Liquid rock (magma) that flows out of a volcano. Fresh lava glows red hot to white hot as it flows.
Lava can reach temperatures of 2000 degrees Fahrenheit, destroying everything in its path.
Ash: Small fragments of lava or rock blasted into the air by volcanic explosions.
A pyroclastic flow is a mixture of rock and hot gases that is blasted out of the volcano at hurricane-force
speeds.
Active Volcano: An active volcano is one that erupts regularly.
Dormant Volcano: A dormant volcano is one that has not erupted for many years, although there is still
some activity deep inside.
Extinct Volcano: An extinct volcano is a volcano that is no longer active and has no chance of
erupting.
Geysers: Geysers are springs that throw boiling water high in the air. They are caused by
volcanic hot spots that warm the ground water. Old Faithful at Yellowstone National
Park is located on a hot spot and is surprisingly regular, erupting every 94 minutes.
Figure 21: Pumice
Pumice: A light-colored volcanic rock containing lots of bubbles from trapped gases.
Basalt: A dark igneous rock. It most commonly forms from hardened lava flow.
Figure 22: Basalt
How does a volcano form?
If there is a shift to the Earth’s tectonic plates, it could cause a volcano to erupt. That is why
scientists pay attention to earthquakes in volcanic regions.
The Pacific Ring of Fire is an area of frequent earthquakes
and volcanic eruptions encircling the basin of the Pacific
Ocean. The Ring of Fire has 452 volcanoes and is home to
over 50% of the world's active and dormant volcanoes. 90%
percent of the world's earthquakes and 81% of the world's
largest earthquakes occur along the Ring of Fire.
Are there different types of volcanoes?
Cinder Cones: Cinder cones are circular or oval cones made up of small fragments of ash and
rock. Because it's mostly loose material, it cannot create tall mountains.
Composite Volcanoes: Tall, steep-sided volcanoes made from many layers of ash, rock, and
lava. They can erupt violently. One of the most famous is Mount St. Helens.
Figure 23: Mount St. Helens before the 1981 eruption.
Shield Volcanoes: Shield volcanoes are made from very hot lava that flows for long distances.
This creates mountains that are rounded. The Hawaiian Islands are made from shield volcanoes.
Figure 24: The entire Island of Maui is a shield volcano.
Volcano safety tips:
Being Prepared:
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Have a disaster plan including evacuation routes and area shelters.
Have an emergency kit with blankets, flashlights, batteries, non-perishable food, can
opener, bottled water, waterproof matches, shovel, windshield scraper, tool kit, jumper
cables, a water container, protective clothing, gasoline, road maps, flares, first aid kit,
instructions how to turn off utilities, a list of emergency numbers, and a battery
operated radio.
During a volcano:
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Follow the evacuation order issued by authorities.
Wear protective clothing like goggles, dust mask, etc.
A volcano to remember:
On March 1, 1980, a new system of seismographs at the University of Washington went into
operation to monitor earthquake activity in the Cascade Mountains. On March 20, it recorded a
magnitude 4.2 earthquake deep beneath Mount St. Helens. This triggered round-the-clock
monitoring of the volcano. On March 27, the volcano gently released steam and ash 6,000 feet
into the air. Shortly after this first eruption a bulge developed on the north side of Mount St.
Helens. The bulge formed from magma pushing up against the peak. Measurements suggested
the bulge was growing at a rate of 5 feet per day. By May 17, part of the volcano's north side
had been pushed upward and outward more than 450 feet. Check out the pictures on the next
page. Can you see the growing bulge?
At 8:32 a.m. on May 18, 1980, a 5.1-magnitude earthquake triggered a sideways eruption on
the mountain's north face removing the upper 1,300 feet of the summit. At the same time, a
mushroom-shaped plume of ash shot 16 miles into the air, eventually covering three states.
Everything within eight miles of the blast was wiped out almost instantly - leaving a barren
wasteland.
Figure 25: Mount St. Helens before the eruption (left) and after (right)