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початковий стан
frictional resistance – опір
тертя

Task 2. Read the text.

Origin of an Earthquake
Earthquakes are natural geologic phenomena caused by
the sudden and rapid movement of a large volume of rock. The
violent shaking and destruction caused by earthquakes are the
result of rupture and slippage along fractures in Earth’s crust
called faults. Larger quakes result from the rupture of larger fault
segments. The origin of an earthquake occurs at depths between 5
and 700 km, at the focus. The point at the surface directly above
the focus is called the epicentre.
During large earthquakes, a massive amount of energy is
released as seismic waves—a form of elastic energy that causes
vibrations in the material that transmits them. Seismic waves are
analogous to waves produced when a stone is dropped into a calm
pond. Just as the impact of the stone creates a pattern of waves in
motion, an earthquake generates waves that radiate outward in all
directions from the focus. Even though seismic energy dissipates
rapidly with increasing distance, sensitive instruments located
around the world detect and record these events.
Thousands of earthquakes occur around the world every
day. Fortunately, most are so small that they can only be detected
by sensitive instruments. Of these, only about 75 strong quakes are
recorded each year and many of these occur in remote regions.
Occasionally, a large earthquake is triggered near a major
population centre. Such events are among the most destructive
natural forces on Earth. The shaking of the ground, coupled with
the liquefaction of soils, wreaks havoc on buildings, roadways, and

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