Section D Directions: In this part, there is one
passage followed by a summary. Read the passage carefully and complete the
summary with the appropriate words from the passage. Remember to write the
answers on the Answer Sheet. Questions 71 - 75 are based on the following
passage. What Causes Earthquakes
People have tried to explain the cause of earthquakes since earliest
times. Some people thought that quakes were sent from heaven to punish the
wicked. Others believed that the earth rested on the backs of animals. We now
have more scientific explanations of the cause of these destructive earth
tremors. Earthquakes are evidence that some process is at work below the surface
of the earth. Large bodies of magma may be in motion. These and other internal
movements can result in a sudden release of energy by breaking the overlying,
brittle rocks. During earthquakes, rocks beneath the surface are clearly bent
and broken. In other cases deformation takes place slowly and without
recognizable earthquake shocks. For example, in a drill hole in the Great Valley
of California, earth movements have been measured for years. The rocks here are
moving at a rote of about one meter per century. In some places pressure slowly
builds up until the rocks break and quickly snap back into position. The
faulting releases energy that may have built up in the rocks for hundreds or
thousands of years. This sudden burst of energy causes vibrations that travel
through the rocks. These vibrations are an earthquake. Most earthquakes are so
small that they can be detected only by sensitive instruments along the fault
surface. However, energy may continue to trickle off in aftershocks. These
shocks are much less severe than the main shock and may continue for months
after the initial earthquake. Summary: Scientifically speaking,
earthquakes are caused when (71) movements of the earth
suddenly release energy by breaking the overlying rocks on the surface. During
earthquake, rocks are clearly bent and broken. Elsewhere, rocks may slowly
(72) over many years. Then the pressure may increase until
the rocks break and snap back. This break (73) the energy in
the rocks and causes vibrations. Most earthquakes are so small that they can be
barely (74) , but large violent earthquakes can destroy
inhabited areas. Sometimes (75) many follow after the first
movement.