Most earthquakes occur within the upper 15 miles of the earth"s surface. But earthquakes can and do occur at all depths to about 460 miles. Their number
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as the depth increases. At about 460 miles one earthquake occurs only every few years. Near the surface earthquakes may run as
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as 100 in a month, but the yearly average does not vary much.
The
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of the disaster in an earthquake depends on many factors. If you carefully build a toy house with an erect set, it will still stand no matter how
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you shake the table. But if you build a toy house with a(n)
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of cards, a slight shake of the table will make it fall. An earthquake in Agadir, Morocco, was not strong enough to be recorded on distant instruments, but it completely destroyed the city. Many stronger earthquakes have done comparatively.
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damage. If a building is well constructed and built on solid ground, it will
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an earthquake. Most deaths in earthquakes have been due to faulty building construction or poor building.
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. A third and very serious factor is panic. When people rush out into narrow streets, more deaths will result.
The United Nations has played an important part in reducing the damage done by earthquakes. It has sent a team of experts to all countries known to be
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. by earthquakes. Working with local geologists and engineers, the experts have studied the nature of the ground and the type of most practical building code for the local area. If
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, these suggestions will make disastrous earthquakes almost a thing of the past.
A. strongly B. sites C. high D. extent
E. pile E violently G. followed H. decreases
I. effected J. resist K. pack L. affected
M. lessens N. subsist O. little