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Earthquakes
An earthquake is one of the worst natural disasters on our earth. We think that the
cause = the reason for something
crust = the top part of the
earth
decade = ten years
disaster = when something
very dangerous happens and a
lot of people die
ground we stand on is very stable, but it isn’t. It moves quite a lot. In the last few
decades scientists have been able to find out why earthquakes happen.
Earthquakes happen when there is a sudden vibration in the earth’s crust. It’s like a
large lorry that travels down your street. When it passes by, you feel your house
shake.
Earthquakes can be caused by a lot of things :
+
Volcanoes that suddenly erupt
erupt = to break out or explode
+
Meteorites that hit the earth
+
Undergrounds explosions
fault = where two plates meet
+
Buildings that fall apart
lorry = a car that carries lots
of goods
But most earthquakes happen because the earth’s plates move.
magma = rock in the inner
part of the earth that is liquid
In the middle of the 20th century scientists found out that continents do not always
plate = the earth’s crust
broke up into many plates and
the continents move on these
plates
earth’s surface is made up of many such plates. Where two plates meet magma
reach = get to
HOW PLATES MOVE
release =let go
stay in the same place. They have been moving on plates for millions of years. The
comes out of the inner part of the earth . These areas are called faults—breaks in the
earth’s crust.
When two plates move away from each other lava or
slide =move, go down
magma comes out of the earth. Most of this happens at the
stable = it doesn’t move
bottom of oceans, where the earth’s crust is very thin. Lava
sudden =unexpected, quick
cools down when it reaches the water and underwater
mountains are formed.
surface =the top layer
towards each other =here:
two objects move to each other
When plates push towards each other—one of
them slides under the other. Rocks are pushed
up and new mountains are formed.
Some plates slide past each other— for example, one
moves north and the other moves south . When these
plates move along faults a lot of energy is released and
the biggest earthquakes happen.
1
Earthquakes
We only hear about earthquakes once in a while , but they really happen every
edge =border ,outer part of
day. There are more than 3 million earthquakes every year—about 8,000 every day
occur = happen
or one every 11 seconds.
once in a while = sometimes
But most of them are very weak or they happen in places where nobody lives. Some
take place = happen
of them take place on the sea floor.
volcano = a mountain that
often explodes and rock, gas
and lava come out of it
WHERE DO EARTHQUAKES HAPPEN ?
weak = not very strong
zone = places, areas
Earthquakes occur all over the world but there are places where they happen more
often. Big earthquakes can be found where plates meet.
80% of the world’s earthquakes happen around the Pacific Ocean—near the east
coast of Asia and the west coast of America. Japan has over 2,000 earthquakes every
year and California and South America are also very active earthquake zones. The
edge of the Pacific Ocean is also called the “Ring of Fire” because there are also
many active volcanoes in this region.
The Ring of Fire
around the Pacific
Ocean
2
Earthquakes
compare = to exchange the
information you have with
others
damage =destruction
direction =way
magnitude = tells us how
strong an earthquake is
man-made = something
caused or made by a person
medium-sized = not so big
and not so small
EARTHQUAKE WAVES
When there is a sudden movement in the earth’s crust, energy moves in the form of
waves . It’s like dropping something into water.
Body waves move through the inner part of the earth and surface waves travel over
the earth’s surface.
Body waves can travel very fast—up to 8 km a second. They travel through rock ,
water and gas . When they reach other places on the earth’s surface they can be registered there. They are usually the first waves to get to the surface.
Surface waves cause the most damage, but they move very slowly. These waves
come at the end of an earthquake.
MAN-MADE QUAKES
movement =when something
moves
Sometimes people can make earthquakes happen. They can fill man-made lakes
rate =rank, measure how
strong something is
these tests can help scientists find out how quakes happen.
reach =go from .... to
registered = recorded
spread out = to move
with water after building a dam—or they test atomic bombs underground. Some of
HOW EARTHQUAKES ARE MEASURED
With a machine called a seismograph scientists can tell where an earthquake happened and how strong it was.
The place in the earth where the movement takes place is called the focus or
Epicentre
hypocentre. From here, waves start to
spread out in all directions. This focus
can be very near to the surface or it can
be hundreds of km below it. The area on
the surface exactly above the focus is
Focus
called the epicentre. This is the place
where the waves hit first and where the
most damage is done.
Whenever an earthquake hits us you hear how powerful it is. The Richter Scale is
used to rate the magnitude of earthquakes. Small quakes have a rating of under 4.
You won’t see a lot of damage here. Medium-sized earthquakes reach between 5
and 7 on the scale, and the really big ones are above 7. The largest earthquake that
has ever been registered was at 9.5 on the Richter scale.
There are more than 100 seismograph stations all over the world. When the earth
shakes seismologists compare the information they get and then they can tell where
the earthquake really happened.
3
Earthquakes
EFFECTS OF EARTHQUAKES
collapse = to fall down
concrete = a very hard material made of cement
developing countries = the
poorest countries in the world
Earthquakes make the ground move. Buildings shake and many of them collapse.
Landslides also happen when rocks get loose.
Another danger is fire. In 1906 San Francisco was hit by a big earthquake and many
houses burned down because they were made of wood.
especially =above all
injured = hurt
landslide = rocks move
down mountains and destroy
houses or block roads
lead to =to be the reason for
loose =movable, to come
free, not fixed
occur = happen
safe water = clean water
The San Francisco earthquake of 1906 destroyed
supplies =reserves
treat =care for, take care of
most parts of the city
When an earthquake occurs on the sea floor, big waves - called tsunamis—hit the
coast. They often come without any warning and they kill many people and destroy
buildings and streets near the coast.
Earthquakes also can lead to diseases, especially in developing countries. When
water supplies are destroyed people don’t have safe water to drink. Sometimes
earthquakes also hit hospitals where injured people are treated.
DEALING WITH EARTHQUAKES
We understand earthquakes a lot better today than we did 50 years ago, but we still
can’t do very much about them. They are so powerful, that we cannot control them.
Scientists can tell us in which regions earthquakes will probably happen, but they
can’t tell us exactly where.
So what can we do about earthquakes ? We can make our houses we live in and
buildings we work in safer. Today architects use materials that won’t collapse when
an earthquake hits—like steel and concrete.
4
Earthquakes
destroy =damage , ruin
height =how high something
THE BIGGEST EARTHQUAKES IN HISTORY
856
200,000 people are killed in one of the deadliest earthquakes in history in
is
Damghan, Iran.
magnitude = how strong or
powerful an earthquake is . It
is measured on the Richter
1138
An earthquake in Aleppo, Syria kills 230,000
scale
record =write down, keep
1556
The deadliest earthquake in history hits Shensi province in China. Almost 1
information
million people are killed.
serious = dangerous
1755
The most serious earthquake in Europe hits Lisbon, Portugal. The whole city
is destroyed. About 70,000 people get killed.
1906
The city of San Francisco is hit by a large earthquake. A big fire destroys most
of the city. About 500 people die.
1908
Messina, Sicily is totally destroyed by a large earthquake . About 70,000 people are killed.
1923
Tokyo, Japan is destroyed by an earthquake with a magnitude of 8.3 .
150,000 people are killed.
1960
The strongest earthquake ever recorded hits Chile. It reaches 9.5 on the Richter scale. 20,000 people die.
1964
The strongest earthquake in North America hits Anchorage Alaska. Ocean
waves reach a height of 20 metres. 200 people are killed.
1976
The biggest earthquake ever recorded in China leaves 242,000 people dead.
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Earthquakes
What can earthquakes be caused by . Give some examples
1.
______________________________________________________________________________________________
2.
______________________________________________________________________________________________
3.
______________________________________________________________________________________________
4.
______________________________________________________________________________________________
What do continents move on ? __________________________________________________________________________
What happens when plates come together ? _______________________________________________________________
____________________________________________________________________________________________________
____________________________________________________________________________________________________
Why don’t we hear about most of the earthquakes ? ________________________________________________________
____________________________________________________________________________________________________
____________________________________________________________________________________________________
What is the “Ring of Fire “ ? ____________________________________________________________________________
____________________________________________________________________________________________________
____________________________________________________________________________________________________
There are two types of waves . Describe them !
Body waves
Surface waves
How do people cause earthquakes ? _____________________________________________________________________
____________________________________________________________________________________________________
____________________________________________________________________________________________________
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Earthquakes
Complete the following text with the words from the box !
damage
surface
recorded
crust
seismograph
hypocentre
seismologists
scale
epicentre
magnitude
directions
With a machine called a __________________ , scientists can tell us where an earthquake occurred and its ____________________ . Every earthquake starts at the focus or
_______________ . This can be near the earth’s __________________ or many hundred kilometres in the earth’s ______________ . From here waves travel in all ________________ . The
area directly above the focus is called the earthquake’s _________________ . This is the area
where most ________________ is done. The Richter ______________ tells us how powerful an
earthquake is. The biggest earthquakes ever __________________ on earth were at 9.5 on this
scale. When an earthquake happens _________________ all over the world compare their information .
Explain in English :
magma _____________________________________________________________________________________________
____________________________________________________________________________________________________
disaster _____________________________________________________________________________________________
____________________________________________________________________________________________________
tsunamis ____________________________________________________________________________________________
____________________________________________________________________________________________________
collapse _____________________________________________________________________________________________
____________________________________________________________________________________________________
volcano _____________________________________________________________________________________________
____________________________________________________________________________________________________
magnitude ___________________________________________________________________________________________
____________________________________________________________________________________________________
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Earthquakes
TRUE OR FALSE ?
T
F
Big earthquakes can be found where plates meet.
The Ring of Fire is around the Atlantic Ocean. Most of the world’s
biggest quakes occur here.
In 1906 many houses in San Francisco burned down because they
were made of wood
Earthquakes that happen on the ocean floor are called tsunamis.
The earth’s crust is thinnest under the continents.
Faults are places where two plates meet. they can be hundreds of
kilometres long.
Earthquakes can also be caused by underground explosions.
Most earthquakes happen after big volcanoes erupt.
When there is a sudden movement in the earth’s crust, energy
moves in the form of waves.
Body waves are fast and travel through all kinds of material
A machine made to find out how strong earthquakes are is called a
hypocentre.
the Richter scale tells you how many people died in an earthquake.
The place above the earth where the most damage is done is called
the epicentre.
Today , it is important to use wood when you build houses or buildings.
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Earthquakes
Write a newspaper report about the picture below !
____________________________________________________________________________________________________
____________________________________________________________________________________________________
____________________________________________________________________________________________________
____________________________________________________________________________________________________
____________________________________________________________________________________________________
____________________________________________________________________________________________________
____________________________________________________________________________________________________
____________________________________________________________________________________________________
____________________________________________________________________________________________________
____________________________________________________________________________________________________
____________________________________________________________________________________________________
____________________________________________________________________________________________________
____________________________________________________________________________________________________
____________________________________________________________________________________________________
____________________________________________________________________________________________________
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Earthquakes
1
2
3
4
5
6
7
8
9
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Across
1.
Down
city in North America that was destroyed 1.
machine that tells scientists how strong
by a big earthquake
an earthquake is
5.
centre of an earthquake
6.
rock in the inner part of the earth that is
buildings that are protect people from
liquid
earthquakes
place on the surface of the earth where 3.
name of the scientist who made a scale
the earthquake waves hit first
to measure earthquakes
7.
9.
Oberfläche
2.
4.
material that is used to build houses and
big ocean wave that is caused by earthquakes
10. what the continents move on
5.
where two plates meet
8.
the top part of the earth
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Earthquakes
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