The Exploding Lakes of Cameroon
blue water，birds，and fish.For the people in the northwestern Cameroon，however, the image is
out of Lake Monoun and came down into the nearby villages，killing thirtyseven people.Two
killed 1,700 people.
collected in the craters of old volcanoes The volcanoes under Lake Nyos and Lake Monoun are
through cracks in the bottom of the lake. This is normal in a crater lake. In most crater lakes，these
bottom of the lake rises and mixes with the water at the top，allowing the gases to escape slowly.
reason for this fact，but as a result，these lakes have more gases tapped at the bottom than other
times more gases.When a strong wind，cool weather a storm，or a landslidecauses the
In the past，no one knew when the gases might explode，so there was no way for the villagers
way to reduce the gas pressure at the bottom of Lake Nyos.They stood a 672-foot plastic pipe in
the top of the pipe，the team put several holes that could be opened or closed by a computer.Now，
up through the pipe into the air like a fountain.With less pressure，a disastrous explosion is much
To protect people nearby until all of the pipes are in place.the scientists have installed early
off loud sirensand bright lights to warn the people in the villages.That way, they will
41 What will happen when Lake Nyos and Lake Monoun explode?
B Poisonous gases will be released suddenly.
D The volcanoes will come to life.
A They were formed in 1984.
C They are not like most other crater lakes.
43 Lake Nyos and Lake Monoun explode because
B people from the villages turn over the water.
D they have more gases trapped at the bottom than other crater lakes
A erected a pressure-releasing pipe in the lake
C built a beautiful fountain near the lakes
45 What do we learn from the last paragraph?
B Scientists still do not know how to prevent gas explosions
D Warning systems have been set up in the villages nearby.