NONFICTION
Imagine you are at the beach. Suddenly, the
water is sucked away from the sand. You hear
a roar. Then you see a huge wall of water
coming towards you. It’s a tsunami (tsooNAH-mee)—a series of the biggest waves in
the world!
Wild, Wild
Waves
Some tsunamis are many miles wide and
taller than a 10-story building. In deep water,
tsunamis can travel as fast as a jet plane can
fly. And when these killer waves reach the
shore, they can flatten a city in seconds.
Practice the Strategy
INFER & PREDICT
1 You predict when you make “best guesses” about
what will happen next based on what you read in
the text. What do you predict this article will be
about? Why do you think so?
infer & predict wild, wild waves
Sundance Comprehension Strategies Kit © Sundance Publishing
Dangerous Waves
The deeper the water, the faster a tsunami wave
travels. But as the wave reaches shallow water
near the coast, it slows down. The water behind
it begins to pile up. At the same time, the
shallow water near the shore is sucked back.
Most tsunamis begin when an earthquake
shakes the ocean floor. This creates strong
underwater waves. Because the water is so
deep, these waves cannot be felt on a boat.
Causes of Tsunamis
Earthquake
Landslide
The wave swells to between 10 and 30 meters
(33 and 100 feet) high and hits the shore with
terrible force. This wave could be followed by
another like it an hour later and then by another.
And the first wave may not even be the biggest!
Volcanic Eruption
Earthquakes cause most tsunamis. But landslides and
underwater volcanic eruptions can also cause tsunamis.
Read What’s T here
Powerful waves
pounding the shore
2 Look at the diagram. What are the events
that can cause tsunamis?
infer & predict wild, wild waves
Sundance Comprehension Strategies Kit © Sundance Publishing
Deep Water Alert
There are two tsunami warning centers in
the world. One is in Alaska. The other is in
Hawaii. Scientists at these centers watch for
signs that a strong earthquake will occur. Then
they warn people on land to move away from
the coast. They also warn ships in the area not
to head for the harbor.
The Pacific Ocean is the world’s deepest
ocean. Ninety percent of all tsunamis have
occurred there. That’s because really big
tsunamis begin in deep water. Also, the
Pacific has many underwater earthquakes.
These earthquakes are caused by movements
in the earth’s crust.
But the warning system doesn’t always work.
Three out of four tsunami warnings issued
since 1948 have been false.
A warning sign in Thailand
T hink About It
3 Why do you think the tsunami warning
system doesn’t always work?
infer & predict wild, wild waves
Sundance Comprehension Strategies Kit © Sundance Publishing
Tsunamis Around the World
History is full of stories about tsunamis.
Nearly 7,000 years ago, a tsunami swamped
the Shetland Islands, near Scotland. In 1755,
huge waves hit Lisbon, Portugal. About
60,000 people were killed.
1964 Alaska
1946 Alaska
1929 Canada
1998 Papua
New Guinea
2004 Indonesia
Tsunamis can travel a great distance from
where they begin. In 1960, an earthquake
occurred near Chile. It caused a tsunami that
hit the coast of Chile. Hundreds of people
were killed. But that wasn’t the end of it. The
tsunami then traveled over 6,000 miles to Hilo,
Hawaii, killing 61 people.
Other deadly tsunamis
1960 Chile
Practice the Strategy
INFER & PREDICT
4 You infer when you use clues to figure out
something that the author doesn’t directly tell
you. Based on what you’ve read, what are some
warning signs that a tsunami might occur?
The most deadly tsunami happened on
December 26, 2004. A strong earthquake in
the Indian Ocean produced a tsunami. Giant
waves hit the coasts of countries in Asia and
Africa. More than 300,000 people were killed.
infer & predict wild, wild waves
1996 Peru
Sundance Comprehension Strategies Kit © Sundance Publishing