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Mechanisms of the Nyos carbon dioxide disaster and of so-called phreatic steam eruptions

1989; Elsevier BV; Volume: 39; Issue: 2-3 Linguagem: Inglês

10.1016/0377-0273(89)90051-6

1872-6097

Haroun Tazieff,

Paleontology and Stratigraphy of Fossils

During the night of August 21, 1986, a huge volume of concentrated CO2 was emitted by the crater (maar) of Nyos, Cameroon. It killed more than 1700 people and all animal life as far as 14 km away. Two hypotheses have been put forward to account for this disaster. The chronologically first one imputes it to have been a phreatic eruption, exceptionally CO2-rich, as had been the case in February 1979 on the Diëng Plateau in Central Java, Indonesia, where the erupting crater was lake-less. The second one claims a limnic origin for the CO2 release, through an overturn of the 220 m-deep Lake Nyos, the hypolimnium of which was supposed to be oversaturated by dissolved gas of volcanic origin. The present paper points to six observed facts for which the eruptive hypothesis easily accounts, and which the authors of the limnic one do ignore.