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What Is Tsunami by alicejenny


									                   Nawamintharachinuthit Triamudomsuksapattanakarn School
 Subject English for Media Information (E 30222) M.5/3-4         Academic Yea r 2011
      Name (Mr./Miss) ……………………………………………… Class M.5/…… No. ……

Read the essay and then answer the questions.

                                    The Causes of Floods

                 Floods are second only to fire as the most common of all natural disasters.
                 They occur almost everywhere in the world, resulting in widespread damage
                 and even death. Consequently, scientists have long tried to perfect their
                 ability to predict floods. So far, the best that scientists can do is to recognize
                 the potential for flooding in certain conditions. There are a number of
conditions, from deep snow on the ground to human error, that cause flooding.

       When deep snow melts, it creates a large amount of water. Although deep snow alone
rarely causes floods, when it occurs together with heavy rain and sudden warmer weather it
can lead to serious flooding. If there is a fast snow melt on top of frozen or very wet ground,
flooding is more likely to occur than when the ground is not frozen. Frozen ground or ground
that is very wet and already saturated with water cannot absorb the additional water created
by the melting snow. Melting snow also contributes to high water levels in rivers and streams.
Whenever rivers are already at their full capacity of water, heavy rains will result in the rivers
overflowing and flooding the surrounding land.

       Rivers that are covered in ice can also lead to flooding. When ice begins to melt, the
surface of the ice cracks and breaks into large pieces. These pieces of ice move and float
down the river. They can form a dam in the river, causing the water behind the dam to rise
and flood the land upstream. If the dam breaks suddenly, then the large amount of water held
behind the dam can flood the areas downstream too.

       Broken ice dams are not the only dam problems that can cause flooding. When a large
human-made dam breaks or fails to hold the water collected behind it, the results can be
devastating. Dams contain such huge amounts of water behind them that when sudden
breaks occur, the destructive force of the water is like a great tidal wave. Unleashed dam
waters can travel tens of kilometres, cover the ground in metres of mud and debris, and
drown and crush everything and creature in their path.

       Although scientists cannot always predict exactly when floods will occur, they do know
a great deal about when floods are likely, or probably, going to occur. Deep snow, ice-
covered rivers, and weak dams are all strong conditions for potential flooding. Hopefully, this
knowledge of why floods happen can help us reduce the damage they cause.
1. Which of the following words are natural disasters?
 (More than one answer may be correct).
       a. flood                  b. earthquake           c. airplane crash       d. typhoon

2. Which of the following are included as causes for floods in the reading passage?
       a. droughts               b. large lakes          c. poorly built roads   d. melting snow

3. How does deep snow cause flooding?
       a. melting snow causes flooding
       b. too much rain causes flooding
       c. sudden warm temperatures combined with heavy rains causes flooding
       d. freezing water causes flooding

4. A broken human-made dam is compared to what?
       a. a tsunami              b. a tidal wave         c. a broken ice dam     d. overflowing

5. Which of the following best describes how a frozen river can cause a flood.
       a. The ice in the river melts too quickly and causes a flood.
       b. The ice in the river cracks causing the water to overflow.
       c. The ice in the river cracks into pieces that eventually create a dam causing
          the water to overflow.
       d. The water behind the ice dam collects and when the dam breaks, it causes
          flooding upstream.

6. How far can dam water travel when it is unleashed from a broken dam?
       a. less than 10 kilometres
       b. tens of kilometres
       c. thousands of kilometres
       d. tens of thousands of kilometres downstream

7. Why does saturated ground contribute to flooding problems?
       a. the ground cannot absorb more moisture
       b. the ground is too hard, so the water runs off
       c. the ground forms a kind of dam
       d. it remains frozen

8. What kinds of problems can floods cause?
       a. death                                          b. widespread damage
       c. destruction of plants and animals              d. all of the above

9. What is the most common natural disaster?
       a. flood        b. fire          c. wind damage          d. rain

10. How does melting snow cause problems related to flooding?
       a. it makes the rivers run too fast
       b. it makes the water too cold
       c. it causes pieces of ice to block the river
       d. it makes the level of the river rise

Choose the best word from the list to complete the following sentences.

  combine             dams           devastating      flooding      human-made
  pieces            potential        prevent             snow        widespread

      Floods cause 1.____________________ damage. Unfortunately, there is little we can do to

2. ___________________ flooding in some situations. There are several causes for

3.____________________ including deep 4. ____________________ melt, icy rivers, and broken

5. ____________________. First, when deep snow melts it creates large amounts of water. When

heavy rain and sudden warm temperatures 6. ____________________ with the deep snow, floods

can occur. Second, rivers that are covered in ice can cause floods when the ice melts. The ice

7. ____________________ form dams which break and cause flooding. Third,

8. ____________________ dams can break and cause 9. ____________________ damage. The water

from these dams can be as powerful as a tidal wave. Our best plan of attack against flooding is

to recognize the 10. ____________________ for flooding in certain conditions.
What Is a Tsunami?
A tsunami (pronounced "soo-nahm'ee") is a series of waves generated by an undersea disturbance such as
an earthquake. From the area of the disturbance, the waves will travel outward in all directions, much like the
ripples caused by throwing a rock into a pond. The time between wave crests may be from 5 to 90 minutes,
and the wave speed in the open ocean will average 450 miles per hour.

Tsunamis reaching heights of more than 100 feet have been recorded. As the waves approach the shallow
coastal waters, they appear normal and the speed decreases. Then as the tsunami nears the coastline, it
may grow to great height and smash into the shore, causing much destruction.

    1. Tsunamis are caused by an underwater disturbance — usually an undersea earthquake. Landslides,
       volcanic eruptions, and even meteorites can also generate a tsunami.
    2. Tsunamis can originate hundreds or even thousands of miles away from coastal areas. Local
       geography may intensify the effect of a tsunami. Areas at greatest risk are less than 50 feet above
       sea level and within one mile of the shoreline.
    3. People who are near the seashore during a strong earthquake should listen to a radio for a tsunami
       warning and be ready to evacuate at once to higher ground.
    4. Rapid changes in the water level are an indication of an approaching tsunami.
    5. Tsunamis arrive as a series of successive "crests" (high water levels) and "troughs" (low water
       levels). These successive crests and troughs can occur anywhere from 5 to 90 minutes apart. They
       usually occur 10 to 45 minutes apart.

Did You Know...

       In 1964, an Alaskan earthquake generated a tsunami with waves between 10 and 20 feet high along
        parts of the California, Oregon, and Washington coasts. This tsunami caused more than $84 million
        in damage in Alaska and a total of 123 fatalities.
       Although tsunamis are rare along the Atlantic coastline, a severe earthquake on November 18, 1929,
        in the Grand Banks of Newfoundland generated a tsunami that caused considerable damage and
        loss of life at Placentia Bay, Newfoundland.
       In 1946, a tsunami with waves of 20 to 32 feet crashed into Hilo, Hawaii, flooding the downtown area
        and killing 159 people.
       In 1906, a typhoon with a tsunami killed an estimated 10,000 people in Hong Kong.
       The Tsunami Warning Centers in Honolulu, Hawaii, and Palmer, Alaska, monitor disturbances that
        trigger tsunamis. When a tsunami is recorded, it is tracked and a tsunami warning is issued to the
        threatened area.
       Most deaths during a tsunami are a result of drowning. Associated risks include flooding, polluted
        water supplies, and damaged gas lines.
       Since 1945, more people have been killed as a result of tsunamis than as a direct result of an
        earthquake's ground-shaking.

Read more on TeacherVision:

Reading Comprehension Test 7 - The Great Hanshin Earthquake

The answers to the following reading worksheet will appear in the box at the bottom of the
page when you click on "Submit Worksheet".

Answer the questions according to the reading passage.

The Great Hanshin earthquake, or the Kobe earthquake as it is more commonly known
overseas, was an earthquake in Japan that measured 7.2 on the Japanese Scale. It occurred
on January 17, 1995 at 5:46 am 52 seconds in the southern part of Hyogo Prefecture and
lasted for approximately 20 seconds. The epicenter of the earthquake was on the northern end
of Awaji Island, near the cosmopolitan city of Kobe with a population of 1.5 million. A total of
6,433 people, mainly in the city of Kobe, lost their lives. Additionally, it caused approximately
ten trillion yen in damage. It is listed in the Guinness Book of Records as the costliest natural
disaster. It was the worst .earthquake in Japan since the Great Kanto earthquake in 1923,
which claimed 140,000 lives.

1. It is stated in the passage that the number of deaths in the city of Kobe ----.

    A) was greater than that of Hurricane Katrina

    B) was not as high as in the Great Kanto earthquake

    C) exceeded that of any known earthquake

    D) was extremely high for an earthquake of this magnitude

    E) was small due to the type of construction

2. According to the passage, the Kobe earthquake is listed in the Guinness Book of
Records because ----.

    A) it has been the highest magnitude earthquake recorded so far

    B) it lasted less than 20 seconds

    C) it caused more financial damage than any other natural disaster in the

    D) the city of Kobe suffered the highest number of deaths among affected

    E) its epicenter was on the northern end of Awaji island

3. We understand from the passage that the Kobe earthquake ----.

    A) is internationally known as the Great Hanshin earthquake

    B) didn't cause any damage in the neighbourhood of Kobe

    C) was the first to cause widespread and serious damage to modern

    D) is not the deadliest earthquake in the history of Japan

    E) had a higher magnitude than the Great Kanto earthquake
                 Nawamintharachinuthit Triamudomsuksapattanakarn School
 Subject English for Media Information (E30222)     M.5/3-4      Academic Yea r 2011
       Name (Mr./Miss) ……………………………………………… Class M.5/…… No. ……

                                   A recent report from the United Nations indicates that the
                                   world's tropical forests are vanishing faster than previously
                                   thought. Up to 50 million acres a year are disappearing, almost
                                   the area of West Germany, 50 per cent more than expected.
                                   The World Resources Institute, which compiled the report,
                                   says that the rising rate of deforestation was "a tragedy for
                                   the biological richness of the earth and an ominous signal for
                                   the climatic conditions of the future." About 100 forest species
become extinct every day, with irreparable loss of part of the world's genetic resources. The report
says that deforestation accounts for a third of the world's emissions of carbon dioxide, the biggest
cause of global warming.

The loss of the forests is largely the result of overpopulation. Hungry landless masses in Asia compete
with commercial logging for the available resources. At the moment, the landless masses are winning.
The overwhelming bulk of the wood and timber of tropical forests is burnt where
it stands. Of that which is extracted, only 17 per cent goes for industrial use.
The rest is used for firewood. The concept of natural forest as spare land ready
for agriculture is predominant. It is the central reality of the deforestation
crisis. In 1988, 60 million acres of Rondonia in the Brazilian Amazon was burnt
for grazing and cropland. Billions of dollars worth of timber went up in smoke,
wasted because there was no ready economic market for it. The forest was seen
to have more value as agricultural land than as standing forests to be harvested.

Just how bad the situation is can be revealed by satellite photograph. Such a photograph of the
Amazon basin will reveal hundreds of points of light stretching from Bolivia to the Atlantic. Each point
of light indicates a man-made forest fire at least half a mile wide. In 1988 and 1989, there were at
least 15,000 such fires which meant that Brazil sent half as much carbon into the atmosphere as

The head of Brazil's environment institute points out: "It's a problem of awareness. Farmers just
don't think of anything but making money, and some regional administrations support them because
they think this is development. In one state, farmers are killing the rubber tappers. In another, they
think only of profits from cattle ranching. They set fire to nature reserves. They could all think about
the environment a little more." The head of the satellite agency which analyzes the problem on a daily
basis is more blunt. He says: "We know that burning in the Amazon is gigantic. It's time they showed
us a wealthy farmer in handcuffs."

                           1.           If you want to know what happens when the rain forests are
                                destroyed, the place to go is Vietnam. During the Vietnam war, the
                                American air force sprayed more than 72 million litres of herbicides
                                and defoliants over the country, dropping bombs and napalm over much
                                of the rest. Almost half of Vietnam's landscape is derelict. Since the
                                end of the war things have got worse: the country's 60 million people,
                                like most inhabitants of the tropics, are dependent upon wood for fuel
                                                                        English for Media Information (E30222) M.5/3-4 p.2

and construction. Demand for fuel and the clearance of land for agriculture has also destroyed
thousands of acres. What the Vietnamese have discovered is that when the tropical forests go, they
go for ever. The soil is poor. Once the cover is gone, tropical rainstorms wash out the nutrients. In the
dry season, the grass catches fire and saplings are killed. Then more top soil is washed away. Tropical
trees flower unpredictably, and their seeds are difficult to collect and germinate.

The Americans, given a choice between being green and fighting the Peruvian drug barons, have chosen,
as one would expect, to fight. The weapon to hand is Spike, a close relative of Agent Orange, the
herbicide used in Vietnam. Spike would have carried deforestation into the densely forested eastern
slopes of the Andes. However, the President of Peru, having made a helicopter flight over the area,
called for a scientific study. He said: "An international scientific team should determine if the
proposal is positive or negative for the environment." He might have added that the Peruvian peasants
and the coca barons can manage their own deforestation quite well without any help from American
herbicides, thank you very much.

It is not only the tropical trees that should fear man's depredations. Even the cactus in the desert
is being uprooted. It seems that the inhabitants of the palatial desert homes of Las Vegas and Palm
Springs require a large cactus as a status symbol, just like a stretch limousine. The finest of the cacti
of Arizona, despite being in protected tourist amenity areas, are being ripped out of the ground by
organised gangs of cactus rustlers. These Saguaro cacti grow as high as five or six metres and weigh
up to four tonnes. Larry Richards works full time as a cactus cop. He says:

"I grew up on this land. I can tell you, in the last 10 years the Saguaros here have been thinned out by,
oh, maybe half. In the next 10 years another half or more of the rest will go. These are prime, saleable
specimens. It's just a matter of time. There are 120 crooked dealers active in Arizona. They use
lifting equipment and large trucks to transport the giants instantly to California, about 400 miles away,
where black market prices are highest, about $40 for every foot of stem, and up to $100 for every
arm which survives the move. A fairly ordinary sample can fetch $800. A big one, $15,000. A whole
generation, covering 60 years of growing, is being wiped out." In one case, the cactus fought back.
It fell on top of a young man who was taking pot shots at it with his rifle, and killed him.

Answer the following questions with reference to the article which follows. Choose from A to G the answers
to the numbered questions.

According to the passage, where is vegetation

        01. ... burnt because there is no market for it? ..................                A. Asia
        02. ... extremely difficult to regenerate? ..................                      B. Amazonia

        03. ... stolen for profit? ..................                                      C. Brazil
        04. ... burnt for pastoral purposes? ..................                            D. Vietnam

        05. ... almost 50 per cent destroyed? ..................                           E. Peru
        06. ... in need of police protection? ..................                           F. Arizona

        07. ... in economic competition with grassland? ..................                 G. Bolivia

        08/09. ... being destroyed in national parks? .....................
        10. ... threatened by a policing action? ..................
        11. ... mostly used for firewood? ..................

        12. ... the subject of competition between peasants and the timber industry? ..................
Animal Instinct
Hours before giant waves pounded coastlines in South Asia, many animals started behaving strangely.
In Sri Lanka, elephants trumpeted frantically and fled to higher ground. Bats and flamingos deserted
lowlying areas. Many other animals escaped unharmed. Wildlife experts are amazed that many animals
survived the tsunami1. The series of huge waves killed thousands of people in South Asia and East
Africa in 2004. Experts say animals might have sensed the approaching waves and moved to higher
ground. "I think animals can sense disaster. They know when things are happening in nature," said an
official at the national wildlife department in Sri Lanka.

                                         Philippe Desmazes/AFP/Getty Images

                       Elephants’ sharp senses may have warned them about the
More Wild Stories
Other stories of odd animal behavior before the tsunami have also surfaced. Giant waves flooded low-
lying parts of Yala National Park in Sri Lanka, uprooting2 trees and killing hundreds of people. Wildlife
officials reported, however, that few animals died. The park is home to hundreds of animals, including
elephants, monkeys, leopards, tigers, deer and water buffalo. In Thailand, elephants carrying tourists
from Japan bolted for the hills, and other elephants broke free of their chains. In one fishing village,
nearly 1,000 locals escaped safely after birds squawked madly.

Making 'Sense' of It
Why might animals have known trouble was on the way? Forget special powers. Instead, experts say
that animals have better senses of hearing, smell and sight than humans do. Those sharp senses help
warn animals when natural disasters, such as volcanic eruptions or earthquakes, are about to happen.
"It doesn't surprise me that animals had an early warning of the tsunami," animal expert Michael Dee
of the Los Angeles Zoo told Weekly Reader. "The senses of certain species are far stronger than
what any human has." Dee points out that dogs, for example, have a stronger sense of smell than
humans and that cats can see better in the dark than people.
Scientists say that animals might have felt the vibrations3 from the earthquake that set off the
tsunami. In addition, many animals, including elephants, pigeons, and dogs, can also pick up infrasound.
That is a sound that is too low in pitch for humans to hear. "Elephants can hear or feel other elephants
grumble up to 2 miles away, so they probably felt the earthquake," said Dee. "Their first instinct would
be to move away from the direction of the sound." An instinct is a natural, untaught behavior or
Before the tsunami struck, animals may have started to flee because they saw other creatures
running. "Animals take their cues from other animals," said Dee.

The Mystery Continues
How animals sense danger has fascinated people for centuries. Most scientists are quick to point out,
however, that nothing has ever been proven.
Will animal instincts be used to create a warning system about natural disasters anytime soon? "I
wouldn't count on [it]," said Dee.
In the meantime, animals are helping out in other ways. For example, elephants are assisting in the
cleanup of areas hit by the tsunami.
         Hearing With Their Feet

                                         Scientists say that elephants can pick up vibrations from
                                         earthquakes through their broad feet. Elephants' toenails
                                         are in the skin and not attached to the toes. Elephants' soles
                                         have sensitive foot pads that detect vibrations, such as those
                                         from an earthquake. That signals elephants to move to more
                                         stable ground.

                          Leigh Haeger

“Animal Instinct” Questions
_____ 1. The author wrote this to
a. advise the readers to listen to their animals.
b. inform the readers about amazing animal instincts.
c. convince the readers to take better care of animals.
d. tell readers about warning signs of natural disasters.
_____ 2. Animals knew that something was wrong, because
a. they felt vibrations in the Earth.
b. other animals were fleeing.
c. they heard low pitched sounds.
d. all of the above.
_____ 3. The author included a quote from Michael Dee because
a. he is an animal expert.
b. he works in Thailand.
c. he survived the tsunami.
d. he wants animals to be treated better.
_____ 4. The author included the diagram
a. to show the sounds that the elephants heard.
b. to show where the elephants were when they heard the
c. to show how elephants can feel vibrations with their feet.
d. to show the size of the elephants’ feet.
_____ 5. How could elephants' instincts help humans?
_DC_ 5. How could elephants' instincts help humans?
Answers will vary. If people paid attention to elephants’ behavior, it _
could possibly provide a warning that there has been an earthquake
or that a tsunami may be coming.____________________________

                                  Causes of Floods

                      3 strong conditions for potential flooding

What causes floods?   How does it happen?

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