Shaking the Earth: Earthquakes and Volcanoes

Written by Robert E. Slavin and Kate Conway

That Ideas

Matter

Shaking the Earth: Earthquakes and Volcanoes

Written by Robert E. Slavin and Kate Conway

Developers: Robert E. Slavin, Kate Conway, Richard Gifford, Alli Hoge, Wendy Fitchett

Editors: Janet Wisner

Designers: Barbara Colquitt, Susan Perkins, Devon Bouldin

Shaking the Earth: Earthquakes and Volcanoes© 2014 Success for All Foundation. All rights reserved.

ISBN: 9781941010105

The mission of the Success for All Foundation is to develop and disseminate research-proven educational programs to ensure that all students, from all backgrounds, achieve at the highest academic levels.

These programs were originally developed at Johns Hopkins University.

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phone: (800) 548-4998 fax: (410) 324-4444 e-mail: sfainfo@successforall.org website: www.successforall.org

Image Credits: Creative Commons Attribution–Share Alike: Eric Gaba (ridges of volcanoes map,

pg. 5), George Mitchell (lava, pg. 19), Hear2heaL (San Andreas fault rocks, pg. 4)Shutterstock.com: Antonio Abrignani, Artkot, Augusto Cabral, Aurin, Bartosz Turek,

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U.S. Geological Survey

1

Table of ContentsShaking the Earth: An Introduction .................................2

What happens in an earthquake? ...................................4

Famous Earthquakes .......................................................8

What happens in a volcano? .........................................12

Famous Volcanoes .........................................................16

Understanding Earthquakes and Volcanoes ..................20

What’s in a seismologist’s toolkit? ................................24

Preparing for Earthquakes and Volcanoes .....................27

Conclusion ....................................................................30

Glossary ........................................................................32

Index .............................................................................33

Shaking the Earth: An IntroductionEarthquakes and volcanoes can be scary, but they are natural events. It’s hard to imagine the ground shaking beneath your feet or a mountain moving. But changes happen deep inside the earth all the time. Usually changes inside the earth happen so slowly that people never notice, but every once in a while the changes in the earth cause violent, destructive events.

EYEWITNESS:

I was standing at my locker and suddenly the earth moved beneath my feet! It sounded like an enormous truck driving by outside and felt like it was shaking the building. The lockers rattled. Papers fell out. Just as I grabbed the door to steady myself, the shaking stopped. What was that? It was quick, but it was the scariest moment of my life.

2

3

During earthquakes, the ground shakes. Sometimes the ground shakes so much that it causes entire buildings to fall down. Earthquakes can even happen deep within the world’s oceans. When that happens, the earthquakes can cause tsunamis, or giant waves, that can cause huge damage in coastal areas.

In a volcanic eruption, changes in the earth allow molten rock, called lava, to flow onto the land, destroying everything in its path. Volcanic eruptions around the world have left behind mountains of ash.

Some places on earth are always in danger from earthquakes or volcanoes. People who live in those areas are prepared for these disasters. This book is about earthquakes and volcanoes, where they are, why they happen, how we can prepare for them, and the importance of knowing how Earth affects our lives.

EYEWITNESS:

I stared at the majestic mountain in the distance. It was the most amazing thing I had ever seen. But suddenly smoke started pouring from the peak. Then, it looked like fireworks shooting from the top of the mountain. I didn’t know what to do! Should I run? Should I call for help? What was happening?

4

What happens in an earthquake?Picture Earth. Do you think that it has always looked the way that it does now? Millions of years ago, all the continents that we know today were part of one supercontinent, or one huge land mass. Inside the earth there are many moving parts. As those parts, or plates, moved and banged into one another, the land mass moved around and separated into continents. This happened very slowly, but the continents eventually separated into what we picture today. In fact, all the continents continue to move due to changes deep within the earth.

Another effect of plates crashing into one another is the creation of faults, or cracks in Earth’s surface. Earthquakes are more likely to occur at these faults. There are multiple fault lines across the globe. The San Andreas Fault runs through California. California can have multiple earthquakes in one day!

s Earth today

t Pangea Earth 200 million years ago

5

An earthquake starts in a specific place along a fault line. This place is called the epicenter. Then, the earthquake sends out vibrations called seismic waves through the rock. In a big earthquake, seismic waves can cause vibrations many miles away. The vibrations are strongest near the epicenter, so buildings and roads near the start of the earthquake are more likely to be destroyed than those far away. The tremors can be so gentle that you wonder if you really felt something, or they can be substantial enough to knock you from your feet. Tremors can last for minutes, and they can continue to come for a long time after the initial quake.

Can you see where the Pacific Plate and the North American Plate come together? That’s where the San Andreas Fault is located. If you live near there, you need to learn what to do in an earthquake!

6

Earthquakes can cause other natural disasters.

Tsunamis: Tsunamis are tidal

waves that surge onto the coast and flood the

surrounding land.

Landslides: Land becomes unstable

during an earthquake, and an earthquake can cause a landslide in mountainous

areas. This is what a landslide looks like.

SENDAI

TOKYO

FUKUSHIMA

JAPAN

Aftershocks: After an earthquake,

there are often smaller quakes called aftershocks. Aftershocks can cause further damage to structures already weakened

by the main earthquake.Aftershocks can last for days

after a main earthquake.

7

EYEWITNESS:

The water level fell. I could see the black mud on the ocean floor. I could see that this was no ordinary tsunami. Then the water came over the sea wall in a giant surge. Boats were thrown over the wall. I ran to the roof of my house. It was petrifying.

Countries and cities along fault lines have learned how to build safer buildings and bridges so they will not be destroyed in an earthquake or a tsunami. Cities that follow safe building codes have much less damage when earthquakes happen. But many structures were built before these codes were established. These are the buildings that often sustain substantial damage during earthquakes.

The Washington Monument was finished in 1884, but it sustained damage from an earthquake and had to be closed for repairs in 2011.

SENDAI

TOKYO

FUKUSHIMA

JAPAN

8

Famous Earthquakes

Missouri A series of earthquakes occurred in New Madrid, Missouri, in 1811. Back then, few people lived in the area where the earthquake happened, and North America did not have seismographs to measure the impact. Estimates of the strength of the earthquakes came from witness reports and newspaper articles. The huge tremors caused tremendous waves that made it appear that the mighty Mississippi River was running backward.

EAR

THQ

UA

KESFACT FINDER:

• There are 500,000

earthquakes a year

worldwide.

• The most powerful

earthquake was 9.5

on the Richter scale.

It happened in Chile

in 1960.

• When several

earthquakes happen

in one area, in a short

amount of time,

scientists call this an

earthquake storm

or swarm.

EYEWITNESS:

I heard a low rumble. Then it hit. The ends of the power lines were hissing like snakes. Brick and glass showered around me. Buildings crumbled like card houses. After the tremors stopped, one of the most devastating sights was the snapped trolley lines—a sign that my city was broken.

9

San Francisco The most famous earthquake in American history was the San Francisco earthquake on April 18, 1906. The earthquake destroyed much of the city, and then fires broke out and destroyed a lot more. More than 2,000 people died, and many more lost their homes.

10

Peru In 1970, an earthquake in Peru set off huge avalanches and landslides of rock, snow, and ice that buried mountain towns and the people who lived in them. The debris from the earthquake demolished many other towns, destroying people’s homes and killing close to 80,000 people.

11

Japan In 2011, an earthquake in the Pacific Ocean caused tremors deep within the ocean that resulted in huge waves. By the time some of the waves reached land, they were 20 feet tall. They hit land and rushed over the walls that had been built to protect the cities. This tsunami flooded cities on the Pacific coast and left a path of destruction. It killed almost 16,000 people.

TSU

NA

MIWhile many people died

in the tsunami, many

animals did not. There are

theories that animals

can sense impending

danger. Perhaps they

felt the tremors from

the earthquake in the

ocean and traveled

to higher ground.

12

What happens in a volcano?A volcano is a mountain that opens downward to a pool of molten rock, or magma, below the surface of the earth. When volcanoes erupt, the magma is pushed out of the volcano and becomes lava. Lava is liquid that flows from a volcano. Lava is extremely hot and is generally bright red because of its heat. Sometimes, lava flows slowly and doesn’t cause any problems. For example, Kilauea, a mountain on the big island of Hawaii, has been erupting slowly for many years, and it causes little damage. However, most volcanoes have magma under a lot of pressure, and when they erupt, watch out!

Mount Saint Helens, Washington State,

one day before the eruption.

The dotted line indicates what disappeared in the eruption.

Mount Saint Helens after the eruption.

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So what causes a volcano to erupt? Just as the plates within Earth cause earthquakes, they also cause volcanic eruptions. When the plates collide or separate, this pushes magma up between them and into the volcano. The magma travels up the center, or throat, of the volcano. The magma is pushed out of the volcano through a hole near the top, which is called the vent. That’s when magma becomes lava. The eruption can be accompanied by a cloud of ash. Then the lava flows down the side of the mountain. Because of its heat and force, lava can destroy anything in its path.

There are three types of volcanoes:

Active: Kilauea in Hawaii Dormant: Mount Ararat Extinct: Mount Ashitaka

Active: They can erupt at any time and erupt often.

Dormant: They could erupt at any time, but they haven’t erupted recently.

Extinct: They haven’t erupted in quite some time, so they probably will not erupt again.

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Volcanoes and earthquakes most commonly occur in the Pacific Ocean’s Ring of Fire. This ring includes the West Coast of the United States and the coast of Japan (map). The Ring of Fire is formed by edges of tectonic plates meeting one another.

EYEWITNESS:

My family and I visited Kilauea, home of Pele, the Hawaiian volcano goddess. I had checked out the webcam footage of the volcano online, but it was nothing compared to seeing it in person. It was a lot harder walking on the cooled lava than I thought it would be. It was jagged and hard. But we finally saw the lava flows. They crept along slowly and looked like bubbles of fire.

15

You might wonder why someone would live near a volcano. Some people choose to risk the dangers of living near a volcano because there are many years between eruptions, and, in the meantime, there are good reasons to live there. First, many minerals can be found in volcanic rocks. Silver, gold, and copper have all been found near volcanoes; many companies mine in those places. Second, after thousands of years, the mineral-rich soil becomes very fertile. The rich soil allows people to farm fruits, vegetables, and flowers successfully. Finally, some people live near volcanoes because of tourism. Because people want to see volcanoes, there are jobs in the national parks, hotels, and restaurants near volcanoes. For these reasons, people think the benefits of living near a volcano outweigh the risks.

EYEWITNESS:

Ashes were falling…followed by bits of pumice and blackened stones, charred and cracked by the flames. You could hear the shrieks of women, the wailing of children, and the shouting of men… many asked the aid of their gods, but still more imagined that there were no gods left…

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Famous Volcanoes

Mount Vesuvius During one famous volcanic eruption that occurred long ago in Italy, Mount Vesuvius wiped out the whole Roman city of Pompeii. Many years later, scientists dug up Pompeii and found thousands of people and animals trapped in the ash from the volcano. Their bodies, clothing, and even the food on their tables were kept perfectly preserved from that terrible day. A writer named Pliny the Younger lived across the bay from Pompeii; his uncle was killed sailing across to rescue people. Pliny wrote about what he saw, leaving us an eyewitness account of the destruction.

17

VO

LCA

NO

ESFACT FINDER:

• There are about

1,500 active

volcanoes on Earth.

• Indonesia has the

most volcanoes.

The country is

formed from many

islands that are

the result of

volcanic activity.

• Volcanoes are named

after the Roman god

of fire, Vulcan.

• There are volcanoes

in the ocean and

on Mars!

Krakatoa In 1883, Krakatoa, a volcanic island in what is now Indonesia, erupted. It caused a tsunami that killed more than 36,000 people. It was so loud that it deafened anyone who was within 10 miles. The sound was heard thousands of miles away. It put so much ash into the air that it blocked the sun and caused cold temperatures for a year. Scientists study Krakatoa to predict when it will erupt again.

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Mount Saint Helens The most famous volcanic eruption in the U.S. was Mount Saint Helens in Washington State. This volcano erupted in 1980, killing fifty-seven people. An earthquake started the eruption. The eruption put the city of Spokane, 250 miles away, in total darkness from the cloud of ash. People wore masks over their faces to protect them from inhaling the ash.

Cleaning up ash after the eruption of Mount Saint Helens in May, 1980.

19

Mauna Loa Mauna Loa is the world’s largest volcano. It most recently erupted in 1984, but it caused relatively little damage. However, it had erupted previously and destroyed entire villages. Mauna Loa is active and the site of scientific research in the study of volcanoes.

Even in the middle of tectonic plates, volcanoes can form because the earth’s crust is very thin. Hot magma under a thin crust creates what is called a hot spot. Mount Kilauea in Hawaii is a hot-spot volcano. In fact, all the Hawaiian Islands were formed from giant volcanoes. As the thin crust moved over the same hot spots, a chain of volcanoes formed, and each volcano became the center of an island.

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Understanding Earthquakes and VolcanoesLet’s take another look at our maps of how Earth used to look and how it looks today. To understand how the land has moved because of plate tectonics, which cause earthquakes and volcanic eruptions, you can cut the map of Pangea (found on page 34) along the continent boundaries. Look at how the land on Earth existed many years ago. Then move the pieces to show how the land on Earth exists today. How has it changed?

s Pangea Earth 200 million years ago

s Earth today

21

The experiment shows us how moving plates have changed the Earth’s land over time. Now let’s look at the effects of plate movement during an earthquake.

You will need:

1 Punch a hole into the center of each piece of cardboard. 2Tie a string through each hole.

3 Lay each piece of cardboard in the pan or box with the string coming out the side.

4Cover the cardboard with dirt.

5 Write down what you think will happen when you pull the strings.

6Quickly pull the strings.

What happened to the dirt when you moved the plates? Was this what you expected?

two pieces of cardboard

a hole punch

string dirt a pan or box

E

A B

C

D

A C

D

EB

22

So, what do you think happens to buildings when the earth beneath them moves, as in our second experiment? Let’s take a look at some model buildings built in shoeboxes. What do you think would happen to each building if we shook the shoeboxes and created an imaginary earthquake? Why?

If you were going to build an earthquake-safe model, how would you build it and why?

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Now let’s see what happens during a volcanic eruption. Look at this experiment:

You will need:

1Put some baking soda into your container.

2Think about what will happen when you add the vinegar.

vinegar

baking soda

a glass container

3Add some vinegar to the baking soda.

What happened when you added the vinegar? Was it what you expected? How was it like a volcano?

A

A

B

C

B

C

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What’s in a seismologist’s toolkit?It could be exciting to be a seismologist. Imagine being the person who figures out how to predict earthquakes, or volcanic eruptions, or if you could find out how to protect people from these disasters! Seismologists have to study a lot of science and math, but if you become one, you could make a real difference in the world.

Would you want to study earthquakes and volcanoes? Why?

Seismograph Seismographs are used to measure the vibrations caused by earthquakes. This figure shows what they look like.

If there is no movement in the earth, the pen on a seismograph shows a straight line, but if there is an earthquake, the length of the lines indicates the size of the earthquake.

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Scientists use the Richter scale to tell the size of an earthquake. The Richter scale measures the energy waves that an earthquake emits. The San Francisco earthquake was an 8 on the Richter scale, and the earthquake in Japan that caused the tsunami was about a 9—one of the biggest ever.

In 1935, Charles Richter invented the Richter scale and it became the standard measure of earthquakes.

The Richter Scale

0 - 1.9

2 - 2.9

3 - 3.9

4 - 4.9

5 - 5.9

6 - 6.9

7 - 7.9

8 - 9.9

9 and over

Can be detectedonly by seismograph

Hanging objectsmay swing

Comparable tothe vibrations of

a passing truck

May break windows,cause small or unstable

objects to fall

Furniture moves, chunks of plaster

may fall from walls

Damage to well-built structures; severe damage to poorly buiilt ones

Buildings displaced from foundations; cracks in the earth; underground pikes broken

Bridges destroyed,few structures left standing

Near-total destruction;waves moving throughthe earth visible tonaked eye

26

GPS Networks Seismologists use many tools to identify changes in the earth. The most modern is the use of global positioning satellite (GPS) systems. You may have heard of GPS and used it in a car or when you’ve gone hiking. Seismologists can use GPS to tell how much of the earth has shifted after an earthquake by getting an initial reading before the earthquake and another reading after the earthquake. They can detect tiny changes. Scientists are constantly monitoring these shifts to understand the changes in Earth.

Scientists who study volcanoes are called volcanologists. Like seismologists, they constantly monitor the earth for changes. Volcanologists collect lava and ash samples from around volcanoes, measure the temperature of the earth and air around them, and study the air around volcanoes for other changes.

Seismologists are working hard to predict when and where earthquakes will happen. They are looking at all sorts of things that might tell people that an earthquake is about to happen. Sad to say, no one knows how to predict earthquakes, but someday this might be possible. Scientists can sometimes predict when volcanoes will erupt. They did predict the eruption of Mount Saint Helens, and people were told to stay away. As a result, only fifty-seven people were killed in that eruption.

Thomas A. Jaggar founded a volcano observatory in Hawaii to predict Kilauea’s eruptions.

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Preparing for Earthquakes and VolcanoesHow do you prepare for an earthquake or a volcano? There are things that you can do before, during, and after these natural disasters to ensure your safety.

Before any natural disaster, make a toolkit with: • water• nonperishable food such as

canned beans and soup• first-aid kit• flashlight• extra batteries• cell phone• battery-operated or solar-powered radio• whistle to call for help

For a volcano toolkit, add:• long-sleeved clothing and long pants• goggles• respirator, or face mask

Check out http://www.ready.gov/kids for more on how to prepare for earthquakes and volcanic eruptions.

Keep your toolkit somewhere you can get to it easily if an earthquake or volcanic eruption occurs, such as beside your bed. Ask your family to come up with an emergency plan that you can all follow.

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EYEWITNESS:

After Mount Saint Helens erupted, I thought I lived far enough away to be safe. But in the middle of the day, the cloud of ash darkened our entire city. We were in the backyard, and my eyes began to burn. My skin was covered in soot, and it was hard to breathe. I ran inside and closed all of our windows. Ash had still gotten inside, so I grabbed a towel and put it over my nose and mouth. It was difficult to see and breathe. The ash lingered for days.

During an earthquake, drop to the ground, get under cover if you can, and hold on. Stay away from the fronts of buildings, where materials might fall on you. If you’re inside your house, stay there, and perhaps get under a sturdy desk. Stay away from glass or anything that could fall on you. Don’t run outside. If you are in a car, ask the driver to stop but stay in it. If you are outside, get away from buildings and power lines.

29

The most important thing to do if you are near a volcano when it begins to erupt is to evacuate the area. Use a car, bike, or whatever is fastest. If you’re in a car or a building, close all the doors and windows so ash and smoke stay outside. Wear long sleeves and pants to protect your skin and goggles, if necessary, to protect your eyes. You may also want to wear a face mask so you don’t breathe in the ash.

After a volcanic eruption or an earthquake, you can begin moving around, but it is still dangerous. The air may be thick with ash or debris. Trees, buildings, and bridges can fall during or after the disaster. Cities in areas where earthquakes and volcanoes are likely to occur are usually well prepared for disaster. Rescuers are trained to help people as quickly as possible. People can go to safe shelters for help. Dogs are trained to go into damaged buildings to find people who are trapped. If the electricity is off, but you have a battery-operated or solar-powered radio, you can listen to it for health and safety announcements.

30

ConclusionEarth is in constant motion. There are entire sciences built around the study of what goes on under the surface. Plates moving and colliding cause our ground to rumble and shake or boiling lava to shoot from mountain tops. These can be unbelievable sights but devastating to the people and towns affected by them.

There have been many devastating earthquakes and volcanic eruptions since the beginning of time, and there will be ones in the future. When and where they will occur is unknown, but people in several professions work every day to try to answer those questions to better prepare all of us for natural disasters.

• Scientists study natural occurrences to try to predict when earthquakes or volcanic eruptions will occur so they can warn people in advance.

• Engineers develop ways to make stronger buildings and bridges that can withstand the movements within Earth. They develop guidelines for safer cities.

• Doctors and other medical professionals come up with plans to address emergencies so when a disaster occurs, hospitals can help people as soon as possible and keep others from getting hurt.

• Teachers and principals work together to figure out how to keep students safe when disasters happen at school.

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Would you like to enter one of these professions to help with natural disasters? Why or why not?

There are many groups that operate worldwide to assist people affected by earthquakes and volcanoes. The American Red Cross provides services to those in need during disaster-relief efforts. The Federal Emergency Management Agency (FEMA) works with state and national organizations to provide relief for victims of disasters as well.

Think about how you can prepare for an earthquake or volcano. If you’re not in an area in danger of earthquakes or volcanoes, how can you prepare for other natural disasters, such as hurricanes and tornadoes? Could you use the advice about preparing a toolkit and a family plan? With proper preparations, lives can be saved, buildings can be kept from collapsing, and cities can be safer places to live—even when the Earth has other plans.

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active: can erupt at any time and erupt often

aftershocks: smaller tremors after an initial, larger earthquake

boundaries: borders

destruction: damage

disaster: tragedy, catastrophe

dormant: inactive, resting

ensure: to make certain

epicenter: where an earthquake starts

eruption: explosion

evacuate: leave

existed: lived

extinct: have not erupted in some time, and probably won’t erupt again

faults: cracks, places on Earth weakened by shifting plates

fertile: abundant

impending: coming, looming

landslides: when ground slides down a slope

molten: melted, liquid

monitoring: watching

nonperishable: will not go bad, decay

previously: before

respirator: face mask to help breathing

seismograph: tool to measure earthquakes

theories: ideas

GLOSSARY

33

Charles Richter .................................25

Chile ....................................................8

disaster toolkit ..................................27

experiment ........................... 21, 22, 23

GPS Networks ..................................26

Pele, Hawaiian volcano goddess ......14

Jaggar, Thomas A. .............................26

Japan ................................. 6, 11, 14, 25

Kilauea ............................ 12, 14, 19, 26

Krakatoa .....................................16, 17

Mauna Loa ..................................16, 19

Mount Ararat ...................................13

Mount Ashitaka ................................13

Mount Vesuvius ................................16

Mount Saint Helens ............. 16, 18, 26

New Madrid, Missouri .......................8

North American Plate ........................5

Pacific Ocean ..............................11, 14

Pacific Plate.........................................5

Pangea .................................................4

Peru ...............................................8, 10

Pompeii .............................................16

Richter scale ......................................25

Ring of Fire .......................................14

San Andreas Fault ..........................4, 5

San Francisco ..................................8, 9

seismograph .................................8, 24

seismologist’s toolkit ........................24

tectonic plates .............................14, 19

volcanologists ...................................26

Vulcan ...............................................17

Washington Monument .....................7

West Coast ........................................14

INDEX

34

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