PHY
Professeur
Activité scientifique
Profil chercheur
Enseignant-chercheur à l’Université de Yaoundé I. Grade : Professeur.
Publications scientifiques
Clement Parfait Bounoung, Françoise Martine Enyegue A Nyam, Hénock Ngoubi, Sarskolin Fosso Kegne, Tabod Charles Tabod
Pramana
Fai Fanyuy Nyuydze, Lukong Cornelius Fai, Afungchui David, Tabod Charles Tabod
Research Square
Agostiny Marrios Lontsi, Joel Fabiola Tchokouata Tchapleu, Alain Pierre Kamga Tokam, Junior Tabi Ndiparray, Delair Dieudonné Etoundi Ndibi, Serge Beteh et 2 autre(s)
Soil Dynamics and Earthquake Engineering
Eddy Ferdinand Mbossi, Etoundi Delair Dieudonné Ndibi, Jean Marcel Abaté Essi, Pauline Nguet Wokwenmendam, Nfomou Ntepe, Mustapha Meghraoui et 2 autre(s)
地震学报：英文版
A compilation of databases from Cameroon and neighbouring countries, including seismicity, stress tensor distribution, gravity, magnetic, topography, lithosphere structure and geological data, is used to define its seismotectonic zonation. Based on the quality and quantity of available data, a seismotectonic map was drawn up through the characterization of subunits of concentrations of earthquake foci and, large neotectonic and structural domains. To prepare this map, a homogeneous earthquake catalogue was compiled from the literature and international data centers dated from 1852 up to 2023. Another point of study was to establish links between seismicity and deformation zones. Many faults and/or structures were identified as possibly active, although some of them are not always associated with seismicity. A seismotectonic model for Cameroon was then built from a classification of faults, neotectonic and seismogenic regions. This structured and highly data-driven approach has been developed specifically for the definition of source zones where seismicity is not well known. The results of the seismotectonic analysis allowed characterizing seventeen seismotectonic source zones in Cameroon. Five source zones are defined in the Mount Cameroon region which is the greatest seismicity activity in the study area. The crustal thickness map of Cameroon revealed a thinned transitional zone interspersed between the thickened Congo Shield and thin Pan-African belt favourable for the development of megastructures such as Central Cameroon shear zone and Kribi-Campo shear zone. This region represents the second highest seismicity zone and contains five source zones.
Cho Louis Akenji, Olivier Holtomo, Tabod Charles Tabod
Chemical Thermodynamics and Thermal Analysis
• The chemical structures are 2-methylpropene (MP) and 2-trifluoromethylpropene (tFMP). • The reactions of title molecules with ● OH radicals are exothermic and feasible at ambient conditions. • The rate coefficients of the reactions are calculated and branching ratios analyzed. • The lifetimes are estimated to be 124.7 days 53.6 days for MP and tFMP, respectively. • The radiative forcing, GWP and POCP are analysed. The Montreal protocol aimed at phasing out refrigerants with high global warming potentials (GWPs), high ozone depletion potential, and then expanding research in developing refrigerants that are more environmentally friendly. Therefore, the investigation of the atmospheric implications on the hydrofluoroolefins 2-methylpropene (MP) and 2-trifluoromethylpropene (tFMP) were done using computational means. These compounds have major applications as refrigerant. The thermochemistry of the process of removal was studied using the PW6B95/Def2-TZVP. This has resulted in the exothermic and spontaneous reactions of MP, tFMP with ● OH radicals. The enthalpy and free energy of reactions as well as the bond dissociations show that the methyl group, -CH 3 , easily releases the H-atom than the other sites of hydrogen abstraction. The kinetics of the said reactions were performed through the MPWB1K/Def2-QZVPP//Def2-TZVP method. The branching ratios of the reaction channels were studied and show that the H-abstraction from the =CH 2 contributes more to rate constant than the other sites containing H-atom. The latter was calculated over a temperature range of 200 – 400 K and was accurately fitted. The rate coefficient at 298 K and 1 atm yielded 9.28 × 10 -14 and 2.16 × 10 -13 cm 3 molecule -1 s -1 . These allowed to assess the atmospheric lifetimes of MP and tFMP, which gave 124.7 days and 53.6 days, respectively. Using the B3LYP/6-31 G (3df,p) level of theory, the radiative forcing efficiencies (REs) were estimated through the IR absorption cross section. The potential energy distribution (PED) of vibrational modes shows that RE is mainly obtained by the torsional vibration H-C-C-C for MP and the stretching of C-F bonds for tFMP. The global warming potentials (GWPs) of MP and tFMP, obtained using their atmospheric lifetimes and REs, yielded low values over the time horizon times 20, 100, and 500 years. The functional group -CF 3 showed lowering effect of GWP. The estimated photochemical ozone creation potential (POCP) are also low for both compounds indicating their very low contribution to ozone production in the troposphere. Therefore, MP and tFMP are both environmentally friendly compounds.
Gah-Muti Salvanus Yevalla, Ebonji Seth Rodrigue, Ndikum Eric Ndoh, Tabod Charles Tabod
Groundwater for Sustainable Development
Gah-Muti Salvanus Yevalla, Rodrigue Ebonji Seth, Ndikum Eric Ndoh, Tabod Charles Tabod
SSRN Electronic Journal
Samndong Cyril Tufoin, Cheo Emmanuel Suh, Tabod Charles Tabod, George Lemewihbwen Ngiamte
Acta Geochimica
Kouamou Njifen Serges Raoul, Eyengue A Nyam Francoise, Fossi Donald Hermann, Bikoro Bi-Alou Marcelin, Ngouokouo Tchikangoua Anita, Bounoung Clement Parfait et 1 autre(s)
Research Square
Abstract In the Campo region, groundwater is critical for human consumption and social activity. Groundwater potential is influenced by a region's geological, geophysical, and hydrogeological factors. The major goals of this research are to determine which regions are ideal for productive groundwater drilling and to assess the source of salinity in the study area's coastal aquifers. The groundwater potential map was created using Geographic Information Systems (GIS) and the Hierarchical Analysis Process (AHP). The process of groundwater mineralization was studied using principal component analysis (PCA). Six variables were taken into account, and weights were assigned to them based on their impact on groundwater recharge. In a GIS environment, spatial integration and a combination of theme layers were conducted. Campo's groundwater potential map was divided into four zones: low 14.4% (389.6 km²), moderate 53.3% (1484.5 km²), high 28.3% (783.3 km²), and extremely high 4.1% (110.9 km²). The results of the PCA reveal a mechanism of water-rock interaction, as a result of geological alteration and a salinization process caused by the intrusion of seawater and human activity The source of salinity in groundwater is manmade (agricultural and residential activities) rather than seawater intrusion. Seawater infiltration is not greatly aided by the low lineament density found near the beaches.
Janvier Domra Kana, Noël Djongyang, Zakari Arétouyap, Kasi Njeudjang, Danwé Raïdandi, Philippe Njandjock Nouck et 2 autre(s)
Geomechanics and Geophysics for Geo-Energy and Geo-Resources
Janvier Domra Kana, Noël Djongyang, Zakari Arétouyap, Kasi Njeudjang, Danwé Raïdandi, Philippe Njandjock Nouck et 2 autre(s)
Geomechanics and Geophysics for Geo-Energy and Geo-Resources
Gah-Muti Salvanus Yevalla, Biyong Bi Mback Emmanuel Blaise, Rodrigue Ebonji Seth, Étienne Totcha Beka, Tabod Charles Tabod
Water Practice & Technology
Abstract Groundwater resources along the coast of Cameroon (Kribi–Campo Sub-Basin) are under siege from point and non-point pollution sources, climate change, urbanization and infrastructure development. This situation is made worse by the absence of a water management and development strategy. Managing and monitoring the area's water resources requires an understanding of the groundwater systems, and thus a thorough understanding of the geology. In this study, a 3D geological model was built from electro-seismic data and the structure of the area's aquifer system developed. The aquifer system structure was transferred into Visual MODFLOW Flex and then used to develop a typical hydrogeological model, which will help the management and monitoring of the area's groundwater resources. As more geological data become available, the current model can be updated easily by editing and recomputing. This work is expected to have a positive impact quite quickly on the provision of potable water and on public health.
Jean Daniel Ngoh, Théophile Ndougsa Mbarga, Kevin Mickus, Yara Tarek, Tabod Charles Tabod
Open Journal of Earthquake Research
The depth to the Curie isothermal point (CPD) was estimated using aeromagnetic data from northern Cameroon. The CPD was estimated using a two-dimensional power density spectral analysis of nineteen 30 × 30 km blocks over a series of Neoproterozoic lithologies associated with the Pan African orogeny. The results show that there are two main regions characterized by the CPD analysis: 1) Shallow depths (~6.37 - 10.09 km) which are located in several regions including the northern portions of the study area (toward the regions of Hina Marbak, Gawel and northern Moutouroua), the southeast (Kaele region), the south (Guider) and the southwest (Mayo Oulo), and 2) deeper depths (~10.68 - 13.72 km) are located in the northeast (Mindif) and southwest (southern Moutouroua, Guider and Bossoum). The shallow depths can be related to two tectonic regimes: 1) the West-Central African Rift System with northeast-trending strike-slip faults emanating from the Gulf of Guinea and 2) the Cameroon Volcanic Line. However, the ultimate source of these shallow regions is interpreted to be related to the Cameroon Volcanic Line based on low seismic velocities imaged by recent broadband seismic studies which are concentrated along the northeast-trending strike-slip faults. An additional finding using the CPD depths, a Curie isothermal temperature of 580°C and a one-dimensional heat flow model, was heat-flow values ranging from 105.68 to 227.63 mW/m2, which are above average global heat flow values and are therefore indicative of potential geothermal resources.
Elad Mkoumbe, Fosso Téguia M. Estelle Eric, Eyike Yomba Albert, Njandjock Nouck Philippe, Tabod Charles Tabod
Open Journal of Geology
A three-dimensional model of the Logone Birni Basin (LBB) is presented by combining gravity and magnetic data and constrained by broad seismic profiles. The 3-D model has revealed the distribution of the stratigraphic formations as well as the top basement variation. Detailed structure of different stratigraphic sequences is presented for the first time for this basin and some of the sequences correlate with established sequences of the neighboring basins. The sediments pill consists of six sedimentary units dating from the Neocomian to the Quartenary. The Makary subbasin or Northern Logone Birni Basin (NLBB) is the deepest part of the basin and may hold good prospect for hydrocarbon generation and accumulation. However, the limited presence of faults and intrusive bodies decreases the possibility of thermal degeneration, contrary to the Central Logone Birni Basin (CLBB) where conditions seem to be fulfilled for possible hydrocarbon generation and maturity. The complexity of the structural pattern of the model is further enhanced by the presences of volcanic bodies, some of which lay directly on basement or interbedded with the sediments layers mainly in the CLBB.
Eyike Yomba Albert, Basseka Charles Antoine, Lordon Djieto Anatole Eugene, Nguimbous-Kouoh Jean Jacques, Alain Zanga-Amougou, Tabod Charles Tabod
Journal of Geoscience and Environment Protection
Gravity and magnetic data were analyzed in conjunction with available geological data to determine the origin of observed positive gravity anomaly at Waza and its possible relationship to mafic intrusions. The data analysis includes the construction of a Bouguer gravity anomaly, isostatic residual gravity anomaly, total magnetic gradient and Euler solutions maps, and two and one-half dimensional gravity models. A positive gravity anomaly that occurs in Waza has amplitude of 35 mGal and can be separated into two parts. The top of the disturbing body causing the anomaly cannot be deeper than 4 km. We believe the anomaly is probably caused by a body of basaltic rocks lying at the upper surface of the Precambrian basement and originate from a self-propagating disturbance of magmatic loads on a pre-existing zone of lithospheric weakness. Melt migration might have been aided by tectonic and flexural stresses, such that the intrusion is limited in extent to the melting region of the plume and did not reach the surface. The model calculated to satisfy the observed anomaly consists of a 2.5 Km-thick slab underlain by a 10.5 km deep column. This model is interpreted to represent a sheet or saucer-like mafic intrusion that has a thick deep feeder. Detailed geophysical studies would be necessary to locate any possible economic occurrences.
Gah-Muti Salvanus Yevalla, Dadjeu Nguemeu Seidou, Bang Vu Ngoc, Tran Van Hoi, Tabod Charles Tabod
Aquademia
Cameroon has several renewable energy sources, including solar, wind, and hydropower. With the liberalisation of the hydroelectric energy sector in Cameroon, rural communities are yet to feel the impact. Small Hydropower projects should have been developed to curb the acute shortage of electricity within these localities and beyond. This is not the case yet. It is in this respect that this study is carried out: to assess the hydropower potential of the Nkam Division and environs and propose sites for the development of hydroelectricity. Geographical Information System, Remote Sensing techniques, and hydrological models (HEC-HMS) were used. Grid analyses were carried out on the Digital Elevation Models (DEMs) using the Watershed Modelling System software to delineate the catchment basin with the sub-basins. Digital Soil and Land use data were obtained from the Harmonised World Soil Data and World Land use Data respectively, which together were used to calculate the Composite Curve Number in QGIS for the various sub-basins. The curve numbers together with other hydrological parameters were used to develop a HEC-HMS deterministic hydrologic model for the catchment basin. The resulting model was calibrated and validated in HEC-HMS, using precipitation data obtained from the localised Yabassi weather station and discharge values from a gauging station at Yabassi. The calibrated peak discharge produced an absolute error of 3.4% and a Nash-Sutcliffe value of 0.301. The hypsometric curve presents a hilly landscape, with 40% of the surface area having elevations of between 10 to 30 m, favouring the development of small scale hydro systems. The RETScreen software was used for the hydro-energy analyses and the estimated potential power, for a hydraulic head of 20 m, stood at 13,813 kW. The values of the Benefit-Cost Ratio value of 1.3 and the Net Present Value greater than zero show that the project is very practical and profitable. It follows that Small and Medium Run-of-River Hydropower Plants can be developed from the Wouri–Nkam Reach, the significant reach in the river network of the Catchment Basin, with an estimated compensation flow of 133.17m3/s for ecological continuity. The project will reduce about 27,064.8 tons of CO2 from the atmosphere.
Jean Daniel Ngoh, Théophile Ndougsa Mbarga, Stéphane Patrick Assembe, Arsène Meying, Olivier Ulrich Owono, Tabod Charles Tabod
International Journal of Geosciences
In this study, we performed some filters to highlight geological structures and/or features which are found in the igneous rocks, between the latitudes 9°45'N to 10°45'N and longitudes 13°15'E to 14°30'E. The application of the first vertical derivative (FVD) and the horizontal gradient magnitude (HGM) on a total magnetic data over the study area has led to put in evidence: 1) geological features as geological boundaries, faults, dykes, folds on the FVD map; 2) abundant aeromagnetic lineaments probably fractures, dykes and contacts, ex-hibit a conjugate relationship suggesting a near NE and NW tectonic trends; 3) existence of a possible prominent near E-W compression, characterized by a possible dextral displacement of geological formations by the shear movements; 4) and the magnetic signature of the country rocks.
Apollinaire Bouba, Joseph Kamguia, Tabod Charles Tabod, Loudi Yap, Robert Nouayou, Kandé Houetchak Ludovic et 1 autre(s)
International Journal of Geosciences
In order to analyze and determine the geological structures of the Adamawa plateau, the terrestrial gravity data were combined to data computed from GGM02C gravity model. The dense gravity net obtained were further introduced into qualitative and quantitative interpretations. The resulting Bouguer anomaly map obtained from combined data shows NE-SW direction which nearly coincides with the main direction of the fractures affecting the basement in the region and indicates strong gradients marking the presence of discontinuities between heavy and negative gravity anomaly. In order to conduct the quantitative interpretation of the combined gravity data, three profiles were drawn on the residual Bouguer anomaly map and therefore were interpreted using spectral analysis method and 3D density inversion. The knowledge of the depth and density of the geological structures show an uplift of dense rocks under the granite-gneiss substratum. This dense material found in the ENE-WSW direction of the Adamawa Plateau is interpreted as basaltic intrusion probably resulting from tectonic processes. According to this study, the depths of 3.83 km and 9.62 km are the new values of depths obtained for futures investigations in the Adamawa plateau.
William Assatsé Teikeu, Jorelle Larissa Méli’i, Philippe Njandjock Nouck, Tabod Charles Tabod, Françoise Enyegue A. Nyam, Zakari Arétouyap
Environmental Earth Sciences
Janvier Domra Kana, Noël Djongyang, Danwé Raïdandi, Philippe Njandjock Nouck, Robert Nouayou, Tabod Charles Tabod et 1 autre(s)
Journal of African Earth Sciences
Ngatchou Heutchi Evariste, Liu Genyou, Tabod Charles Tabod, Joseph Kamguia, Sévérin Nguiya, Tiedeu Alain et 1 autre(s)
Geodesy and Geodynamics
We used the Earth Gravitational Model (EGM2008) data sets to analyze the regional gravity anomalies and to study the underground structures in Cameroon. We first created a high-resolution Free-Air anomaly database, then corrected the gravity field of the topographic effect by using ETOPOl DEM with a resolution of 0.01° to obtain the Bouguer anomaly, then applied a multi-scale wavelet-analysis technique to separate the gravity-field components into different parts of shallow-to-deep origins, and finally used the logarithmic power spectrum technique to obtain detailed images and corresponding source depths as well as certain lateral inhomogeneity of structure density. The anomalies of shallow origin show successive elongated gravity “highs” and “lows” attributable to subsurface Tertiary and lower Cretaceous undulations. Our results are in good agreement with previous investigations.
Fidèle Koumetio, Donatien Njomo, Constant Noutchogwe Tatchum, Alain Pierre Kamga Tokam, Tabod Charles Tabod, Eliézer Manguelle-Dicoum
International Journal of Geosciences
The gravity maps display, in Bipindi zone, local oval culminations of low anomalies indicative of a presence of intrusive light body in a subsurface but the nature, the form and the position of this body are still unknown. The analyses of established gravimetric anomaly maps, the multi-scale evaluation of maxima of gradients and the quantitative interpretation of residual anomalies by 3D modelling permit characterizing the intrusive light body situated at Bipindi. The multi-scale evaluation of maxima of gradients shows that the modelling of the intrusive light body of Bipindi can be done without the problem of interference of anomalies from different sources. The 3D model of Bipindi zone shows two dissymmetrical blocks of the same type of rock with a density contrast of -0.095 g·cm-3 in comparison with the density of the surrounding metamorphic rocks. The two blocks are at a distance about 3 km from one to another. The upper surfaces of these blocks lie at a depth between 1 and 2 km. Their lower surfaces have two landings; one lies at a depth of about 8 km and another at a depth about 14 km. A consideration of the density of the modelled body, of the ranges of densities of specific rocks present in the general region indicates that the body may be composed of nepheline syenites. The intrusive body of Bipindi is situated in a senestral shear zone. The area situated between the two blocks of this intrusive body may be indicated for a detail study in the domain of mineral research.
Owona Angue Marie Louise Clotilde, Tabod Charles Tabod, Sévérin Nguiya, Kenfack Jean Vıctor, Tokam Kamga Alain Pierre
Open Journal of Geology
Gravity method is among the most applied geophysical methods in mineral and oil exploration. It may help to identify fault networks which are of interest for mineral exploration. Potential field data can give valuable information on the location of faults in the basement. These faults may have propagated into the overlying sedimentary rocks and influenced fluid flow and distribution of hydrocarbon traps and mineralization zones. A study was therefore conducted in south Cameroon with the aim of highlighting the different lineaments of the region, which were completely or partially hidden by the sedimentary cover. Different gravity data processing techniques including horizontal gradient coupled with upward continuation and Euler deconvolution were used. The application of these methods has mapped out a number of lineaments depicting gravity density discontinuities whose directions are NS, NE-SW, EW and NW-SE. The predominant direction for major lineaments is NE-SW. The major lineaments associated to the faults are: the Kribi-Edea faults, Ambam faults, Ebolowa-south of Yaounde faults; Bipindi-Yaounde faults; Pouma-Yaounde fault and the fault system which crosses the east, north, west of Monatele city. Euler solutions indicate depths up to18 km for the roof of the faults. The main results worked out from this study provide with new elements that allow the improvement of the knowledge on the structure of the study area. The structural map obtained shows major tectonic events that are responsible of the structural layout of the study zone. In addition, information related to the dip and depth of the various structures was also obtained. The map of lineaments is a useful tool for the planning of hydrogeological and/or petroleum investigations.
William Assatsé Teikeu, Philippe Nouck Njandjock, Théophile Ndougsa‐Mbarga, Tabod Charles Tabod
International Journal of Geosciences
Yaounde zone is originally characterized by the small number of aquifers and bad renewal capacity. Within the frame-work of the emergency program which aims at supplying the city with drinking water, seventeen Vertical Electrical Soundings (VES) were carried out using Schlumberger configuration in parts of Yaounde (latitude 3o- 5oN and longi- tude 11o-13oE) to determine the nature and thickness of aquifer zone and necessary geoelectrical parameters. Four to five geoelectric layers were delineated from the survey area. The first layer is the topsoil and has resistivity values ranging from 13 - 216 Ω·m and thickness is between 0.1 - 6 m. The second layer made up of clay sand and laterite has resistivity values ranging between 23 and 923 Ω·m and thickness ranged from 1 and 40 m. The third and fourth geoelectric layers consisting of clay and gneiss/migmatite with thickness varying from 1.7 - 63.3 m correspond to an aquifer horizon. Resistivity values of the aquifer ranges from 4 to 9215 Ω·m. The study indicates that average depth of the aquifer is 20 m and average thickness of the aquifer is 55 m. Soundings curves suggest several four layered geoelectrical sections KH, KQ, HK type and some five layered sections of the HKH, KHK types. KH type is dominant and can be used as reference for future studies. The resistivity survey reveals that the parameters obtained through interpretation of VES curves corroborate the litho logs of boreholes from the area.
Akoumou Manga Ngando, Robert Nouayou, Tabod Charles Tabod, Eliézer Manguelle-Dicoum
Geofísica Internacional
La falla de Adamawa es una estructura tectónica relacionada con la línea volcánica de Camerún. Se han obtenido datos ATM a lo largo de una superficie de case 1,600 km² alrededor de la ciudad de Tibati. El conocimiento geológico del área es escaso; los últimos datos se recopilaron hace 50 años. Este artículo describe las etapas principales, seguidas de la determinación de la firma electromagnética de la falla. Los resultados muestran numerosas zonas anómalas atribuidas a la zona de Cizalla. Todo ello nos permiten inferir la estructura de la resistencia eléctrica y hacen posible tener conocimiento acerca de la falla Tibali. Estos resultados son preliminares a un estudio de la estructura de esta falla precámbrica. En este estudio se produjeron valores y variaciones importantes de la aparente resistencia. La falla de Tibali se caracteriza por su gran complejidad y estrechez.
Jean Victor Kenfack, Jean Marie Tadjou, Joseph Kamguia, Tabod Charles Tabod, Bekoa Ateba
International Journal of Geosciences
A new gravity survey of the Mount Cameroon area has enabled the definition of four major gravimetric domains, which coincide with the recognized structural units. In order to determine the nature of superficial and deep structures in this mountainous zone, new gravity data have been processed. These new gravity data was integrated to existing gravity data to propose the new complete Bouguer anomaly map of the region, and then to show major characteristics of the Bouguer gravity of this area. The interpretation of gravity patterns (bouguer maps) in terms of geological data, shows that the Mount Cameroon zone belongs to a wide positive anomaly; these anomalies display complex gravity domains, which seem to be similar to that due to major structural units in the region and volcanic activity of the mountain. In the mountain active zone in particular (between 2000 and 3800 m of altitude), the new anomaly map shows high gravity anomalies (from 11 to 60 mgal), coupled with low gravity at some stations (in the summit, 4060 m) where gravity anomaly is about -30 mgal. The steep WNW-ESE gravity gradients observed on the gravity maps mark the transition between positive in the south and negative anomalies.
Philippe Njandjock Nouck, Eliézer Manguelle-Dicoum, Théophile Ndougsa‐Mbarga, Tabod Charles Tabod
Geofísica Internacional
Se presenta un mapa de anomalías residuales de gravedad para la cuenca de Yagoua, Camerún. Esta cuenca se encuentraal NW de la cuenca de Doba, productora de hidrocarburos. Una anomalía negativa de -18 mGal es interpretada como unaformación sedimentaria (arenisca) de 3.1 km de espesor. La estratigrafía se comprueba mediante análisis espectral y modelaciónen 2.5 D.
Agostiny Marrios Lontsi, Joel Fabiola Tchokouata Tchapleu, Alain Pierre Tokam Kamga, Junior Tabi Ndiparray, Delair Dieudonné Etoundi Ndibi, Serge Beteh et 2 autre(s)
SSRN Electronic Journal
Ferdinan Nzouemou, Narcisse Gaetan Tepoule Dongmo, Tabod Charles Tabod, Eric Ndikum Ndoh, Raymond Soweh Mbinkong, Serge Hugues Pokam Kengni
Modeling Earth Systems and Environment
Ferdinan Nzouemou, R.A. Yossa Kamsi, Tabod Charles Tabod
SSRN Electronic Journal
Oumarou Sanda, Mabrouk Djeddi, Tabod Charles Tabod, Jean Marcel, Jean Marcel Abaté Essi, Thibaut Aloys Ekani Mebenga et 1 autre(s)
Advances in Science, Technology & Innovation/Advances in science, technology & innovation
Makem Elvise Abasoh, Kenfack Jean Vıctor, Pierre Wotchoko, Njoh Oliver Anoh, Paho Nteinmusi Jude, Demanou Messe Malick Roosvelt et 1 autre(s)
Results in Geophysical Sciences
The main aim of this study is to carry out a hydrogeological assessment to reveal suitable sites for the implantation of hydraulic structures like water boreholes. Petrographic studies put into place granitic rocks with numerous biotite in the Northern part of the map and basaltic rocks with phenocryst of olivine in the South. Lineaments extracted from satellite images revealed two major trends of N50–60°E and N70–80°E. A total of sixty-four Vertical Electrical Sounding (VES) data were acquired using Schlumberger configuration array, 2-D sections and hydraulic parameters of aquifers were deduced. The geoelectric sections characterize the subsurface into four geoelectric layers namely: topsoil with (resistivity values lower than 300 Ω m), weathered basement with (resistivity values ranging between 300 and 600 Ω m), fractured basement (resistivity ranging between 600 and 800 Ω m) and a more or less fresh bed rock with resistivity value up to 4000 Ω m. The hydraulic assessment of aquifers revealed a high conductivity value of 34 m/day, porosity of 41% and a high transmissivity of 429 m2/day indicating a highly interconnected fractured basement of the study area. Groundwater potential map revealed Toungang, Lafé and Ndionkou villages as suitable sites for water boreholes implantation with an average aquifers roof depth ranging between 1to 31 m.
Paho Nteinmusi Jude, Kenfack Jean Vıctor, Pierre Wotchoko, Njon Olivier Anoh, Makem Elvise Abasoh, Demanou Messe Malick Rosvelt et 1 autre(s)
Results in Geophysical Sciences
The characterization of the Pouma-Cameroon quartzite deposit with the aim of determining its lateral extension along the Douala-Yaoundé axis required, among other things, the examination of the petrographic and morpho-structural domain as well as the determination of the electrical properties of the formations in the study area. 24 vertical electrical sounding points were carried out using a Schlumberger type electrode configuration; also, 7 manual auger boreholes were carried out, these resulted on one hand in the following types of curves: KH, QH, AKH, H, HK, AK, HA, A; and on the other hand to lithological logs with a clayey sandy texture, gravelly clayey sand to lateritic. The calculation of the densities as well as the petro-structural studies made it possible to confirm the geological context of the study area. The various results obtained permitted us to locate the fresh quartzite formation at the center of the study area. It stretches along the Douala-Yaoundé axis over 1871.4 m for the fresh formation and 1991 m for the slightly altered formation.
Eddy Ferdinand Mbossi, Delair Dieudonné Etoundi Ndibi, Pauline Wokwenmendam Nguet, Jean Marcel Abaté Essi, Edouard Olivier Biboum Ntomb, Jacques Dili-Rake et 2 autre(s)
Open Journal of Earthquake Research
West Africa is considered a region of low seismicity. However, the monitoring of earthquake activity by local seismic arrays began very early (as early as 1914) in West Africa but seismic catalogs are very incomplete. In 1991, Bertil studied the seismicity of West Africa based on networks of seismic stations in Ivory Coast and neighboring countries. The reference work of Ambraseys and Adams as well as the recent earthquakes given by the international data centres on the seismicity of West Africa were also used for the computations of earthquake hazard parameters. Different earthquake event data have been compiled and homogenised to moment magnitude (Mw). The obtained catalog covers a period of over four centuries (1615-2021) and contains large historical events and recent complete observations. The complete catalog part has been subdivided into four complete subcatalogs with each a level of completeness. The minimum magnitude and the maximum observed magnitude are equal to 2.89 and 6.8 respectively for the whole catalog. The seismic code software developed by Kijko was used to calculate the earthquake hazard parameters. The results give a b value of 0.83 ± 0.08 for the whole period and preliminary seismic hazards curves are also plotted for return periods 25, 50 and 100 years. This is a good and practical example showing that this procedure can be used for seismic hazard assessment in West Africa.
Oumarou Sanda, Mabrouk Djeddi, Tabod Charles Tabod, Jean Marcel, Simon Ngos, Jean Marcel Abaté Essi et 1 autre(s)
Arabian Journal of Geosciences
Marcelin Bikoro-Bi-Alou, Théophile Ndougsa‐Mbarga, Tabod Charles Tabod
A quantitative interpretation of aeromagnetic data is conducted in the Ebolowa-Djoum area. The aim of the study is to estimate magnetic and geometrical parameters of the causative bodies using spectral analysis and 2.5 modeling. In addition an indicative evaluation of the volume of magnetic material is done using geoinformation mapping tool. The techniques are applied to three N-S profiles (P1, P2 and P3) that cross three anomalies at Kamelon (P1), Ngoa (P2) and between Djoum and Olounou (P3). The application of the techniques cited above has given the following results: (1) Magnetic bodies identified have susceptibility with a range that coincides to iron formations such as magnetite and haematite; (2) the depth to the top of the iron formation that produce the observed magnetic anomalies varies from 88 m to 109 m at Kamelon, 32 m to 670 m at Ngoa and 50 m to 580 m along the profile P3; (3) the depth to the foot of that formations is from 614 m to 1240 m at Kamelon, 802 m to 965 m at Ngoa and 250 m to 1340 m along P3; (4) an E-W extent (strike) of iron formations is 12000 m at Kamelon, 1600 m to 12000 m at Ngoa and 12000 m in the P3 profile; (5) a N-S extent (width) of iron formations ranging from 2390 m to 77470m at Kamelon, 3680 m to 9600 m at Ngoa and 1540 m to 13140 m in the P3 profile; (6) indicative volume value of that iron formations varies from 10.1 km 3 to 16.3 km 3 at Kamelon, 0.7 km 3 to 8.7 km 3 at Ngoa and 1.20 to 18.0 km 3 along profile P3.
Thomas D. A. Keleko, Jean Marie Tadjou, Joseph Kamguia, Tabod Charles Tabod, Alain N. S. Feumoe, Jean Victor Kenfack
Journal of Water Resource and Protection
A geoelectrical survey using the electrical resistivity method was carried out in some villages in the western region of Cameroon to investigate the sub-surface layers and evaluate the characteristics of aquifers. The direct current electrical resistivity method was utilized for the present study. Applying the Schlumberger array, a total of twenty four (24) Vertical Electrical Soundings (VES) were conducted. Quantitative and qualitative interpretations of data were carried out to determine the nature and thickness of the aquifer zone combined with existing litho-logs aided correlation of geoelectric sections to litho-logs. Four to five geoelectric layers were delineated from the survey area. The first layer which is the topsoil has resistivity values ranging from 6 - 949 Ωm and the thickness is between 0.2 - 4.2 m. The second layer which is made up of clay and laterite has resistivity values ranging between 9 - 1862 Ωm and thickness range from 1.0 - 16.4 m. The third and fourth geoelectric layers are made up of clay and granite/basalts with thickness varying from 2.2 - 39.5 m which corresponds to an aquifer horizon. Resistivity values of the aquifer ranges from 10 to 70,506 Ωm. The resistivity map drawn from these measurements shows the presence of a low resistivity zone which indicates the reflection in the direction of ground water from northeast to southwest with the recharge concentrated to the south of the study area. This study has revealed for this area, an average depth of the aquifer of 32 m with the average thickness of the aquifer being 22 m. The geoelectric sections of some VES stations demarcated corroborate very well with the geological description of the area.
Pouyon Dieudonné Epada, Sylvestre Ganno, Tabod Charles Tabod
International Journal of Geosciences
Geophysical and geotechnical surveys were conducted in the Western Cameroon (Kekem area) following a landslide on argillaceous material in order to understand the triggering processes and mechanisms of this landslide and to assess the stability of the slope. The geophysical soundings consisting of vertical electrical soundings with the Schlumberger electrode array configuration were carried out to monitor the behaviour of electrical resistivity in the landslide. Geoelectrical data showed a zone of low resistivity values identified as a clayey sand-filled aquifer. This aquifer played an important role in the triggering process of the landslide. Geotechnical soundings showed that the aquifer had a thickness of 7.0 m. The depth from the landslide crest level to the failure surface reached 3.0 m and 20.6 m. Laboratory tests were then carried out in order to evaluate the cohesion of the soil and the angle of internal friction, and to calculate the safety factor in view of making a stability analysis. The laboratory results exhibited a soil with low consistency, almost doughy. The mean value of the safety factor (1.4) been lower than the slope stability coefficient (1.5), revealed that the slope is unstable, likely to know at any moment a reactivation of the slide. This study showed that electrical soundings coupled with geotechnical surveys are useful tools for the characterization of landslides.
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