IJG  Vol.5 No.11 , October 2014
Study of Multi-Origin Hazards and Assessment of Associated Risks in the Lefo Caldera (Bamenda Volcano, Cameroon Line)
The Bamenda Volcano (BV) (2621 m) is a stratovolcano situated in the Cameroon Line (CL). BV includes Mount Lefo (2534 m) which is situated on its southern slopes and contains one elliptical caldera (3 × 4 km). This caldera is propitious to farming and breeding activity. Despite these profitable assets, Lefo caldera (LC) is an amphitheater of the occurrence of multi-origin hazards that have direct or indirect impacts on the biodiversity and human patrimony. The most present hazards are those of meteorological origin. Numerous combined factors (steepest slopes, heavy rainfalls, weathered state of volcanic products…) rule these hazards. These factors gave rise to the occurrence of landslides, gullies erosion and rock falls which occur precisely on caldera northern and eastern rims. Hazards of anthropogenic origin are based on the destruction of the vegetation cover by the population for dealing, firewood and building issues. Moreover, during the breeding activity, the cattle covers the caldera throughout the day; this unevens the topography and destroys the meadow. Hazards of volcanological origin are not yet occurring in LC; but the recent Lake Monoun (1984) and Nyos (1986) CO2 eruptions, mount Cameroon eruptions (1999 and 2000) and mount Oku Lake event (2011) which are close to the BV and, the age of 0 Myr of basalt, constitutes a subject of controversy toward the reactivation of the Cameroonian hotspot faults. The assessment of risks in LC was based on the average income of breeding activity and house investment. The economy of LC is valued at about US$527472.527. The level of such risk will be important in case of loss of human beings and the destruction of geomorphosites’ values. In order to reduce the level of looses in this zone, hazard and risks maps are provided in this paper as well as some recommendations.

Cite this paper
Ghislain, Z. , Guimolaire, N. , Armand, K. , Merlin, G. and Pierre, K. (2014) Study of Multi-Origin Hazards and Assessment of Associated Risks in the Lefo Caldera (Bamenda Volcano, Cameroon Line). International Journal of Geosciences, 5, 1300-1314. doi: 10.4236/ijg.2014.511107.
[1]   Tchoua M.F. (1974) Contribution a l’etude geologique et petrographique de quelques volcans de la Ligne du Cameroun. (Monts Manengouba et Bambouto). These Doct. Etat, Univ. Clermont-Ferrand, 337.

[2]   Fitton, J.G. (1987) The Cameroon Line, West-Africa: A Comparison between Oceanic and Continental Alkaline Volcanism. In: Fitton, J.G. and Upton, B.G.J., Eds., Alkaline Igneous Rocks, Geol. Soc. Special Publication, London, 273-291.

[3]   Deruelle, B., Moreau, C., Nkoumbou, C., Kambou, R., Lissom, J., Njonfang, E., Ghogomu, R.T. and Nono, A. (1991) The Cameroon Line: A Review. In: Kampunzuet, A.B. and Lubala, R.T., Eds., Magmatism in Extensional Structural Settings, Springer-Verlag, Heildelberg, 274-327.

[4]   Bardintzeff, J.M., Deruelle, B., Wandji, P., Ngounouno, I., Lissom, J., Nkouathio, D. and Fosso, J. (2001) Les eruptions 1999-2000 du mont Cameroun et les risques associes. GSAf 12: Geo-Environnemental Catastrophes in Africa. Journal of Cameron Geoscience Society, 1, 29-30.

[5]   Ghogomu, T.R., Tangumonkem, E.T., Tiethop, A.C. and Linonge, O.N. (2001) Landslides in the Bamboutos Region, Western Cameroon. GSAf 12: Geo-Environnemental Catastrophes in Africa. Journal of Cameron Geoscience Society, 1, 54-55.

[6]   KagouDongmo, A., Wandji, P., Pouclet, A., Nkouathio, D.G. and Tchoua, F.M. (2005) Le mont Manengouba (Ligne du Cameroun), Un volcan benefique, mais potentiellement dangereux, typologie des aleas et evaluation des risques naturels associes. Africa Geoscience Review, 12, 97-109.

[7]   Zoning, A., Ngouanet, C. and Tiofack, O. (2007) The Catastrophic Geomorphological Processes in Humid Tropical Africa: A Case Study of the Recent Landslide Disasters in Cameroon. Sedimentary Geology, 199, 13-27.

[8]   Zangmo Tefogoum, G., KagouDongmo, A., Nkouathio, D.G. and Wandji, P. (2009) Typology of Natural Hazards and Assessment of Associated Risks in the Mounts Bambouto Caldera (Cameroon Line, West-Cameroon). ActaGeologicaSinica, 5, 1008-1016.

[9]   Zangmo Tefogoum, G., KagouDongmo, A., Nkouathio, D.G. and Wandji, P. (2011) Hazards Zonation and Assessment of the Associated Risks in the Mount Manengouba Calderas (Cameroon Volcanic Line). IAG Regional Conference, Addis Ababa, 146.

[10]   Zangmo Tefogoum, G., KagouDongmo, A., Nkouathio, D.G., Wandji, P., GountieDedzo, M., Kamgang, P. and Nono, A. (2012) Multi-Hazard Study and Assessment of Associated Risks in the Lefo Caldera of Bamenda Volcano (Cameroon Volcanic Line). The Magmatic Rifting and Active Volcanism Conference, Addis Ababa, 166-167.

[11]   Zangmo Tefogoum, G., Nkouathio, D.G., Kagou Dongmo, A., Wandji, P. and Gountie Dedzo, M. (2013) Study of Landslide hazards and Assessment of Associated Risks in the West-Cameroon Highlands (Central Africa). 8th International Association of Geomorphologists, Paris, 654.

[12]   Nechia Wantim, M., Kervyn, M., Ernst, G., Suh, C.E., Jacobs, P. and Marmol, M.A. (2012) Assessing Lava Flow Hazard at Mount Cameroun Volcano, West-Central Africa with a Parabolistic Maximum Slope Model. The Magmatic Rifting and Active Volcanism Conference, Addis Ababa, 11-13 January 2012, 163.

[13]   Gountie Dedzo, A., Kamgang, P., Njonfang, E., Zangmo Tefogoum, G., Kagou Dongmo, A. and Nkouathio, D.G. (2012) Mapping and Assessment of Volcanic Hazards Related to the Ignimbritic Eruption by AMS in Bambouto Volcano (Cameroon Volcanic Line). The Open Geology Journal, 6, 72-84.

[14]   Guedjeo, C.S., Kagou Dongmo, A., Ngapgue, F., Nkouathio, D.G., Zangmo Tefogoum, G., Gountie Dedzo, M. and Nono, A. (2013) Natural Hazard along the Bamenda Escarpment and Its Environments: The Case of Landslide, Rock Fall and Flood Risks (Cameroon Volcanic Line, North-West Region). Global Advanced Research Journal of Geology and Mining Research, 2, 15-26.

[15]   Toteu, S.F., Van Schmus, W.R., Penaye, J. and Michard, A. (2001) New U-Pb and Sm-Nd Data from North-Central Cameroon and Its Bearing on the Pre-Pan African History of Central Africa. Precambrian Research, 108, 45-73.

[16]   Nzolang, C., Kagami, H., Nzenti, J.P. and Holtz, F. (2003) Geochemistry and Preliminary Data on the Neoproterozoic Granitoids from the Bantoun Area, West Cameroon: Evidence for a Derivation from a Paleoproterozoic to Archeancrust. Polar Geoscience, 16, 196-226.

[17]   Nzolang, C. (2005) Crustalevolution of the Preacambrianbasement in West Cameroon: Inference from Geochemistry, Sr-Nd and Experimental Investigation of Some Granitoids and Metamorphic Rocks. Ph.D. Thesis, Graduate School of Science and Technology, Niigata University, Niigata, 207 p.

[18]   Zangmo Tefogoum, G., Nkouathio, D.G., Kagou Dongmo, A., Wandji, P., Gountie Dedzo, M., Kamgang, P. and Nono, A. (2013) Characterization of the Geoheritage of Lefo Caldera and Its Surroundings (Mount Bamenda, Cameroon Volcanic Line). The 24th Colloquium of African Geology, Addis Ababa, 7-13 January 2013, 344.

[19]   Kamgang, P., Chazot, G., Njonfang, E. and Tchoua, F. (2008) Geochemistry and Geochronology of Mafic Rocks from Bamenda Mountains (Cameroon): Source Composition and Crustal Contamination along the Cameroon Volcanic Line. Comptes Rendus Geoscience, 340, 850-857.

[20]   Kamgang, P., Njonfang, E., Nono, A., Gountie Dedzo, M. and Tchoua, F.M. (2010) Petrogenesis of a Silicic Magma System: Geochemical Evidence from Bamenda Mountains, NW Cameroon, Cameroon Volcanic Line. Journal of African Earth Sciences, 58, 285-304.

[21]   GountieDedzo, M., Nedelec, A., Njanko, T., Nono, A., Font, E. and Launeau, P. (2011) Magnetic Fabrics and Sources of Miocene Ignimbrites from West-Cameroon. 23rd Colloquium of African Geology, Johannes Burg, 8-14 January 2011, 164.

[22]   Ngounouno, I. (1998) Chronologie, Petrologie et cadre geodynamique du magmatisme cenozoique de la Ligne du Cameroun. In: Geosc. Au Cameroun, Ed., collect. Geocam, 1/1998, Press of University of Yaounde I, 169-184.

[23]   Suchel, J.B. (1972) La repartition des pluies et les regions pluviometriques au Cameroun. Contribution a l’etude des climats de l’Afrique tropical. MESIRES-ORSTOM, Yaounde, 260 p.

[24]   Olivry, J.C. (1986) Fleuves et Rivieres du Cameroun. Mesres-Orstom, Paris, 733.

[25]   Suchel, J.B. (1988) Les climats du Cameroun. These de Doct. D’Etat, University of St Etienne, Saint-Etienne, 4 Volumes, 1188 p.

[26]   Varnes, D.J. (1978) Slopemovement Types and Processes. In: Schuster, R.L. and Krizek, R.J., Eds., Special Report 176: Landslides: Analysis and Control Transportation and Road Research Board, National Academy of Science, Washington DC, 11-33.

[27]   Ayalew, L. (2000) Factors Affecting Slope Stability in the Blue Nile Basin. In: Bromhead, M., Dixon, N. and Ibsen, M., Eds., Landslides: In Research, Theory and Practice, Thomas Telford, Cardiff, 101-106.

[28]   Nyssen, J., Poesen, J., Moeyersons, J., Deckers, J., Haile, M. and Lang, A. (2003) Human Impact on the Environment in the Ethiopian and Eritrean Highlands—A State of the Art. Earth-Science Reviews, 64, 273-320.

[29]   Wolle, W.M. and Hachich, W. (1989) Rain-Induced Landslides in Southeastern Brazil. Proceedings of the 12th International Conference on Soil Mechanics and Foundation Engineering, Vol. 3, Rio de Janeiro, 1639-1642.

[30]   Alcantara-Ayala, I. (2002) Geomorphology, Natural Hazards, Vulnerability and Prevention of Natural Disasters in Developing Countries. Geomorphology, 47, 107-124.