Limnic Eruptions
and Lake Nyos
Limnic Eruptions
A limnic eruption is a rare natural disaster that occurs in large lakes. They occur when large amounts of carbon dioxide which is dissolved in the lakes waters, usually originating from underground gas chambers, escape the water, usually assisted by strong winds, earthquakes, or volcanic eruptions. The gas then collects into a singular, heavy cloud. This is also known as a lake overturn.
Limnic relates to any large body of water with a low concentration of salt, such as a freshwater lake.
As these clouds consist of CO2, they are unbreathable, which is unfortunate as the clouds are heavier than air, making them sink to the ground, suffocating anything in their path and being able to continue to travel downhill and stay as a singular cloud for days. Not many animals can survive this, including humans, however a few of the suffocated animals can wake up if the cloud passes quickly enough, but only to find other members of their species suffocated to the extreme of death.
These eruptions are known for also causing tsunamis if the overturn is violent enough. Lakes known for previously erupting or that have large carbon dioxide concentrations are known as limnically active lakes, or EXPLODING LAKES.
Two limnic eruptions have happened in recent history, one in 1984, located at Lake Monoun in Cameroon, West Africa, and another in 1986, located at Lake Nyos, also located in Cameroon.
Lake Nyos, located in Cameroon, West Africa, is the most recent example of a limnic eruption.
On the 21st of August 1986, lake Nyos overturned, believed to be caused by a nearby volcanic eruption, landslide, or the cooler water in the lake moving to one side. This caused 100,000 to 300,000 tones of straight carbon dioxide to be released from the lake, forming a cloud 100 meters high. This cloud flowed down the Mbere Rift Valley to nearby settlements. The rumbling noises previously made by the eruption lead many locals out of their homes to investigate, many of which dropped unconscious because of the unbreathable level of carbon dioxide.
Of the two closest settlements to Lake Nyos, Nyos and Kam, only four people miraculously woke up. They witnessed their neighbours, local livestock and family members on the ground, as they themselves were previously, however, all but these four had died of suffocation.
Due to the lack of oxygen, cars and any other form of engine-powered transport would not be able to run.
For reference, the average amount of CO2 in most average air is around 1 tenth of a percent, and the maximum amount breathable by humans is 15 percent, but during the events of Lake Nyos, the closest measurement to lake nyos was found to be about 10 percent. This means that lake Nyos and the closeby towns most likely surpassed 15 percent, which would cause humans and other animals airways to shut off and knock them unconscious, leaving only plants in their natural state, other than closeby farmland that was hit by a 24-meter high tsunami caused by the eruption.
The cloud rumbled along the valley for 25 kilometres over the time of two days, suffocating anything and anyone in its path. The further away from the lake, the better chance the locals had of surviving as the carbon dioxide would be diluted with air.
By August 23rd, the cloud was finally diluted enough for the air to once again be breathable. Many recent victims of the cloud were able to wake up, some to also find their neighbours, local livestock, and family suffocated.
Lake Nyos
a Bovine found near Lake Nyos
Mist of water
and CO2 gas
polythylene
pipe
shut off valve
Ballast
boundary Layer
CO2
ritch
At least 1700 people were found dead during these events, along with about 3500 cattle.
This led to scientists measuring the carbon dioxide levels in other similar lakes, most of which were located nearby. Of these lakes, one caught the immediate attention of scientists. lake Kivu, located in the democratic republic of Congo, is about 2000 times the size of lake nyos, or 2700 square kilometres. Its waters have an extremely high level of CO2, which leads to a limnic eruption occurring around every thousand years, and almost everything living within the waters to also die out every thousand years.
Scientists have found a way to avoid further limnic eruptions. First, the lake must be identified to have large amounts of carbon dioxide in its waters. Secondly, a large straw-like tube is constructed, and finally, the tube is placed close to the point of the gas's origin, acting like a staw to let the gas slowly be released into the air instead of being released at once during an eruption.
These pipes and their electronics must have ongoing maintenance to stop them from eroding due to the CO2 making the water slightly acidic. however, multiple pipes would need to be installed in a single lake to decrease the rate of dissolving gas.
In 2018, an 18-month attempt to fully degass Lake Monoun was approved, and through the use of these pipes, the lake has since been rendered safe to the public.
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https://en.wikipedia.org/wiki/Limnic_eruption https://science.howstuffworks.com/environmental/earth/geophysics/lake-nyos.htm https://en.wikipedia.org/wiki/Lake_Nyos_disaster https://dbpedia.org/page/Limnic_eruption https://everything-everywhere.com/limnic-eruptions-the-rarest-natural-disaster/