The Lake is a killer
Mohammed Musa Abdullahi woke up Saturday morning sick and sluggish. The day before he fell ill and lay down right in the school building. Abdulahi went to the house and suddenly noticed that the streets of his village, in North-West Cameroon, frightening silence reigns. Roads and yards of Soboma were littered with corpses. People were lying as if dead on the go or in the middle of a conversation with a neighbor. Killing all dogs, all the cattle, the trees fell dead birds and insects.
So on August 21, 1986 in the village on the shores of lake Nyos killed 11 family members Abdulahi and 1,700 of his countrymen. He survived because he was in a locked office, in a school built on a hill.
The lake before the disaster
The lake after the crash
Nyos is a lake of extraordinary beauty – surrounded by mostly cultivated fields, picturesque rocks and green hills. Pearl-gray surface serenely calm, but deep continuously is the accumulation of explosive forces. Nyos is a crater of a once active volcano, after the eruption of which five centuries ago on the bottom left igneous plug. It is cooled and compressed under water pressure. Such lakes around the world are many, but only two are able to kill all life on their shores. The second lake – Monoun – is located 95 kilometers to the Southeast of Nyos. And both of them ready at any moment to explode.
As it was
Because of deep volcanic activity, which is still ongoing, carbon dioxide is constantly being raised through the pores in igneous rock. Meets with groundwater dissolves in them and with them falls into the lake. In the bottom layers of the lake accumulates a hell of a mixture, which does not mix with the upper layers. Usually in crater lakes water is periodically stirred, aerated waters rise to the surface, and gases without harm to the natural environment are scattered in the atmosphere. But in Nyos and Monone the boundary between the layers is not disturbed.
Gas continues to saturate the deeper layers of water until some external event will not disturb them. It can be strong wind and waves, unusually cold weather (when the upper layers of the water cool down and descend to a depth), landslide or earthquake. Part of the deep water rises from the bottom, carbon dioxide is released from solution and bubbles rushes up, pulling even more bottom water. The inertia of the process increases rapidly: a few bubbles turn into a gas stream, and finally from the open bottle of champagne, highly carbonated water fountain breaks up. In 1986 in Nios like this “fountain” beat to a height of 80 meters, and everything was drowned in a cloud of carbon dioxide.
Heavy, twice as heavy as air, gas down on the lake shore and choked all life in its path. When in August 1984 exploded lake Monoun, 37 people were killed. Lake Nyos is bigger and deeper, so deadly force would claim many more lives. The cloud of gas spreads around the neighborhood at a speed of over 70 kilometers per hour and quickly gets even to the villages located 20 kilometers away from the lake. The last one was killed by the explosion Nyos, a girl, the morning after the eruption came down the hill to the hollow, gas-filled.
How will it be?
Lake Nyos is sure to explode again. According to the latest data, now in the lake two times more carbon dioxide than it was during the previous explosion (0,4 cubic kilometers, and now only 0.17 cubic kilometers in 1986). A disaster can destroy the fragile dam in the Northern part of the lake, and its waters then escape into the territory of Nigeria, where flooding of settlements of over 10,000 people.
Despite the fact that after the disaster in 1986 3,500 people were evacuated from the shores of the lake and settled in safe areas, many are back – they are attracted by the fertility of the local land and rich vegetation. Corn fields in the South are suited to the water, on the slopes of the hills grazing cattle, which are looked after by shepherds Fulani tribe. Moreover, in the early 90’s some European researchers released in bezrybe long to poison its inhabitants, the lake of tilapia – fish from the rocks ciclico. This experiment has led to the fact that the fish are bred in huge numbers, and the locals are not seriously interested in fishing.
In 1999 in Cameroon arrived international group of scientists to investigate deadly lake and, if possible, to find a way to rid it from the poison gas accumulating in depth. But the distance from large settlements complicates the task: to thoroughly examine and especially to Degas the lake in a hurry impossible. Although the project degassing exist, he has no money. Helped assemble them even the support of UNESCO. After all charitable organizations accustomed to correct the consequences of accidents already happened, not prevent them.