Earthquakes

EARTHQUAKES

A FORCE OF NATURE

I.                    On March 11, 2011, a 33-foot-high tsunami hit northern of Japan, causing the country´s worst destruction and loss of life since World War II. The tsunami was triggered by an earthquake in the Pacific Ocean. Measuring 9.0 on the Richter scale, the earthquake, was the sixth largest ever recorded by seismologists.

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II.                   Not only that, it shifted the earth´s axis by 10 inches. This deviation led to shortening of the length of a day by 1.8 microseconds! Earthquakes hit the headlines only rarely; but events like Japan´s megaquake serve to remind us of their awe-inspiring power. Every year some 3 million earthquakes take place on the planet – equivalent to about 8,000 a day or one every 11 seconds. (     )

III.                 Earthquakes happen because the earth´s crust is not contiguous. Rather, like a boiled egg with a broken shell, it is separated into 20 pieces. These pieces are called tectonic plates. The theory that explains the movement of these plates on the earth´s surface is known as plate tectonics. According to plate tectonics, the earth ´s plates are not stationary but are instead moving very slowly around the planet. (     ) 

IV.                The result is that sometimes the plates crush into each other, sometimes they move away from each other, sometimes they slide past each other. (     )

V.                  Take, for example, plates that are sliding horizontally past each other. Because the edges of the plates are rough, they get stuck, the rest of the plate keeps moving. (     )

VI.                At some point (i. e., when the plate has moved far enough), the edges suddenly become unstuck. The sudden-unsticking and jerking apart of the plates releases the built-up pressure in an instant. The result is an earthquake.

VII.              There is a special region of the globe known as the Pacific Ring of Fire (     ).  In The pacific ring of fire, plates are crashing each other constantly. When two plates crash together, one of two things can happen. Either one plate is forced to slide beneath the other one, or the two plates push against each other to form mountains and volcanoes. In either case earthquakes can result.

VIII.            Earthquakes in the pacific ring of fire result from plates colliding and sliding under each other. (     )

IX.                It was the pacific plate sliding under the Eurasian plate that caused the earthquake and the tsunami in Japan on that fateful day in March 2011.

Activities:

1.       THESE ARE SEVEN SENTENCES REMOVED FROM THE TEXT, CHOOSE FROM THE SENTENCES BELOW ( A- H)  AND PUT THE RIGHT LETTER IN THE PARENTHESIS. BE CAREFUL THERE IS ONE EXTRA YOU DON´T NEED.

a)      The result is an enormous build-up of pressure.

b)      It is the movement of plates at their edges that causes earthquakes

c)       So great was its power that it caused the entire island of Japan to move 16 feet eastwards.

d)      It is the explanation for mountains and volcanoes, not just earthquakes.

e)      The sudden drop of one plate below another, when it occurs under the sea can generate a tsunami.

f)       Most are so small and are unnoticed, but a few, about 20 a year, are big enough to cause damage.

g)      It is that an incredible 90% of all earthquakes, and 80% of the world´s largest earthquakes, occur.

h)      Because the plates are interconnected, no single plate can move without affecting the others.

2.       SUMMARIZE THE VIDEO YOU WATCHED AS HOMEWORK, USE ONLY 50 TO 60 WORDS. YOU MAY USE THE TEXT IDEAS.