I-MAG STS    Corporation
On the morning of August 16, 1984 thirty-seven people living near Lake Monoun never awoke. Hundreds more were seriously
ill. Eventually, the American geologist Haraldur Sigurdsson concluded the lake had  overturned, releasing clouds of odorless
and colorless but very lethal carbon dioxide gas that travelled more than twenty kilometers. He feared that there might be
similar deadly lakes. His analysis was rejected by reviewers at
Science magazine as far-fetched. Actually, Professor Sigurdsson
was near-fetched: On August 21, 1986 about 100 kilometers to the north Lake Nyos overturned, killing 1800 people. In the
photo (above right) taken about a week after the event note the brownish color of the lake (should normally be blue) and the
marked scarring (light brown areas) along the formerly green, heavily planted shores. Lake Nyos is 2 kilometers by one
kilometer and barely 200 meters deep - probably 2000 times smaller than Lake Kivu. It has been calculated that 1.6 million tons
of carbon dioxide (about 1 cubic kilometer) escaped. We expect at least 50 to 60 times this much gas from Kivu.  Two years ago
Dr. Isaac Njilah, a geologist at the University of Yaoundé, repeated a warning that the natural dam of volcanic rock that keeps
in Lake Nyos' waters could collapse. 50 million cubic meters of water would flood into areas of the Northwest Province and the
Nigerian states of Taraba and Benue - we calculate 20,000 people are at risk. The Cameroon government, speaking through Dr.
Gregory Tanyi-Leke of the Institute of Mining and Geological Research, acknowledged the weakening but denies any
immediate threat. A United Nations team led by Olaf Van Duin and Nisa Nurmohamed of the Netherlands Ministry of
Transport and Public Works inspected the dam and believes that the dam will breach in the next 10 or 20 years. Jack Lockwood
and others first published predictions of dam failure in 1988. Olivier Leenhard in 1990 predicted a maximum of 30 years away,
but Sam Freeth essentially predicted never. We would be inclined to reduce lake water level by twenty meters and accelerate
degassing. There is a webcam at http://perso.orange.fr/mhalb/nyos/indexwebcam.htm