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SPEAKING
10
a
Work in groups of three. Read one short text each
about a volcano and make notes on the key points.
Student A:
look at page 155.
Student B:
look at page 157.
Student C:
look at page 161.
10
b
Presenting
Take turns to give a one-minute
presentation on your volcano from your notes. At the
end of each presentation, ask the presenter polite
questions about their volcano.
MEET THE EXPERT
Watch an interview with Dr Andrew
McGonigle, a volcanologist, about active
volcanoes.
Turn to page 150 for video activities.
Yellowstone:
BEAUTY... AND THE BEAST
SIX HUNDRED AND FORTY
THOUSAND YEARS AGO,
a massive volcanic eruption
occurred in the north-west of
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the United States. It created a
huge crater, or caldera, which
is now part of Yellowstone
National Park. The volcano is
still active and, if it erupts
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again, the ash cloud could
make over half of the United
States uninhabitable.
The same geographical features
that make Yellowstone so
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dangerous also make it a great
tourist attraction. There are
hot springs, bubbling mud
pots, steam vents and geysers,
including the famous
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‘Old Faithful Geyser’, which
erupts every 35-120 minutes,
sending hot water up to fifty
metres into the air. However, all
these attractions are evidence
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of hidden dangers below the
surface.
Yellowstone is a supervolcano
and sits on top of a magma
crater that is as large as the
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park, about 72km from one
side to the other and about
13km thick. Underneath that,
reaching down to an incredible
2000km below the Earth’s
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surface, is a reservoir of molten
rock. The pressure of all this
volcanic activity has already
caused the land to rise about
half a kilometre above its
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natural position and there’s a
very real danger that there will
be another super-eruption one
day. The question is, when?
Unfortunately, that’s something
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even the experts don’t know.
Volcanology is a comparatively
new science and our knowledge
is constantly changing. Our
understanding of volcanoes is
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generally based on observation
and, when scientists observe a
new phenomenon, they have to
tear up their old theories and
start again.
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A good example of the
unpredictability of volcanoes is
Vesuvius, near Naples in Italy.
It was once very active, with
regular eruptions for many
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hundreds of years, but, since
1944, it has been quiet. Is it
now dormant or is the magma
building up towards another
hugely destructive eruption?
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Back in Yellowstone, experts
are wondering how much
warning they would have of any
serious volcanic activity. There
would possibly be some
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changes in the behaviour of the
geysers and steam vents and
there would almost certainly be
an increase in the number of
earthquakes in the area.
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However, there are earthquakes
in the area all the time, most
undetectable except to scientific
instruments, and nobody
knows how obvious the signs
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would be or how far in advance
they would start.
Mount Ontake in Japan is one
of the most closely monitored
volcanoes in the world but,
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when it erupted in 2014, there
were only eleven minutes
between the first warning signs
and the eruption. Tragically,
many hikers were caught by
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surprise and couldn’t escape in
time.
Yellowstone attracts over three
million visitors a year, mostly
during the summer months.
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The roads are narrow and get
very crowded. It can take half a
day to get from one side of the
park to the other. If an eruption
occurred without much
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warning on a busy summer’s
day, it would be impossible for
everyone to escape in time.
