Language Lab, Science Faculty, University of Nice - Sophia Antipolis

 

Home / Earth Science / Lake Nyos - Part III

General Vocabulary

 

Here is the complete version of the text. When you are ready to go on, here is the link to Part IV of the exercise.

 

   cloud      disturbance      earthquake      eventually      heavier      levels      pours      reached      release      spontaneously      suffocated      surrounding      triggered      unfortunate  
Over time, the lowest levels of the lake become more and more saturated with gas. And eventually, when they reach 100% saturation, the gas can bubble spontaneously out of the lake, creating a foaming column of carbonated water. This eruption, or release, can be triggered even before saturation is reached, for example by a landslide, an earthquake, a violent storm, or another disturbance of the waters.

The eruption itself isn't dangerous, but the suddenly released cloud of gas can be fatal. Carbon dioxide is heavier than air, and when released, it pours over the rim of the crater and slides down into the surrounding low-lying valley. Carbon dioxide normally makes up 0.03% of air, and concentrations of more than 10% can be fatal. The unfortunate villagers around Lake Nyos literally suffocated under the heavy poisonous cloud of gas.