ST
Maître de Conférences
Scientific activity
Researcher profile
Faculty researcher at the University of Yaoundé I. Grade: Maître de Conférences.
Scientific publications
Victor Metang, Liliane Njips Nantchou Goudjou, Brigitte Domkam, Steve Franck Bamou-Wandji, Viclair Daina Jouanang, Clarisse Rosine Bikaga and 2 more
SSRN Electronic Journal
Ange Merveille Guedia Meguedong, Callitus Gentry Fuh, Sylvestre Ganno, Dieudonné Bisso
Journal of African Earth Sciences
Sylvie Durande Djikam Patipe, Philémon Zo’o Zame, Dieudonné Bisso, Yasmina Boussafir, Guillaume Veylon, Sylvestre Ganno
Discover Applied Sciences
The Lagdo dam in northern Cameroon, built between 1978 and 1984 with an initial capacity of 72 MW (now reduced by half), is the primary source of hydroelectric power for the northern grid. This 40 m high embankment dam (190 m base width, 10 m crest width) holds 7.7 billion dm³ of water. Its core is composed of clayey sand, complemented by horizontal filters and drains, while granite and gneiss riprap protect the embankments. Despite its strategic importance, the Lagdo Dam lacked a safety monitoring system based on international standards. Instrumentation records piezometric fluctuations with early operational peaks followed by recent declines. Displacement monitoring shows initial significant horizontal and vertical movements, stabilizing over the last two decades. Visual inspections revealed several anomalies including cracks, embankment degradation, overgrown vegetation, termite mounds, erosion traces, and water leaks, all of which compromise the safety of the structure. The over 40-year-old Lagdo Dam is classified as a Class A dam, and its monitoring system must comply with international standards. In addition to routine inspections, it is crucial to include scheduled, special and in-depth inspections.
Jospin Fomat Tandjong, Victor Metang, Descartes Newton Youmssi Metang, Liliane Njips Nantchou Goudjou, Natacha Abigaelle Fosso Simo, Viclair Daina Jouanang and 2 more
Results in Earth Sciences
The eastern region of Cameroon, rich in gold resources, remains underexplored due to the geological complexity of the Pan–African basement and the scarcity of outcrops. This study aims to identify the structures controlling gold mineralization in the Batouri district by integrating gravity analyses, field observations, structural mapping, and petrographic studies. Terrestrial gravity data and the global EGM2008 model were used to detect density contrasts at different scales, allowing the identification of faults, shear zones, and intrusive bodies potentially controlling mineralization. Field investigations revealed biotite granite outcrops that are cut by fractured and altered quartz veins, together with swampy areas conducive to the accumulation of alluvial gold. Petrographic analyses show a predominance of quartz and feldspars, consistent with the occurrence of primary gold mineralization. The synthetic structural map highlighted three main lineament trends (N77–90°E, N30–60°E, and N105–120°E), providing a precise framework for designing targeted exploration grids. The integration of gravity, structural, and petrographic data reduces uncertainties in deposit localization, optimizes exploration campaigns, and guides prospecting towards the most favorable areas. These findings provide a solid basis for future detailed investigations, contributing to a better understanding of lithostructural controls on gold in a complex geodynamic context and supporting economically viable gold exploration projects.
Pieride Mabe Fogang, Bingjie Huo, Hervé Losaladjome Mboyo, Hai Rong, Songtao Zhang, Lesly Dasilva Wandji Djouonkep and 1 more
Scientific Reports
Deep coal mining induces geomechanical perturbations that threaten aquifer integrity. This study develops an analytical model coupling Fourier's heat conduction and Cauchy's momentum equations to predict groundwater depletion under dynamic stress from vibrations (0-6 MPa). Laboratory tests on Datong Mine samples (coal seam No. 12) yielded baseline parameters, including soil cohesion (C = 1.0 MPa) and Poisson ratio (ν = 0.35). The simulation uses an effective elastic modulus (E = 12.5 GPa) to represent the fractured coal-rock mass under vibrational loading. Results show vibration-induced fractures increase permeability by 15-25% initially, but subsequent compaction reduces it by 60%, with peak vertical displacements of 0.18 m. Vibrational loads exceeding a critical stress magnitude of 6 MPa exacerbate hydraulic conductivity variations, altering pore pressure distributions and threatening aquifer integrity. The model, validated via ABAQUS simulations, provides a scalable tool for mitigating water loss in mining environments. This research highlights the criticality of harmonizing geomechanical simulations with hydrogeological assessments to advance groundwater management strategies. The proposed analytical solution offers a scalable solution for mitigating environmental and operational risks across diverse mining geologies, ensuring resource sustainability and operational resilience against geohydrological instabilities.
Ange Merveille Meguedong Guedia, Dieudonné Bisso, Lionel Mbida Yem
Chronicle of computing
In order to determine the geothermal potential of the municipality of Baré-Bakem, located in both the sedimentary basin of Moungo and the volcanic region of Nkongsamba (Cameroon Volcanic Line), geophysical measurements using electrical resistivity tomography were conducted along a 1km profile between two opposing thermal sources spaced 20 meters apart. The profile was acquired in the SW-NE direction using a 945m-long array with 64 electrodes spaced at 15 meters intervals. The ZZRes2Dinv44 software was employed to generate investigative images. The obtained results along the profile reveal the presence of two geothermal zones of interest trapped within permeable sedimentary formations at depths ranging from approximately 20 to 110 meters and close to the surface. From a geothermometric perspective, chemical geothermometers such as silica and Na-K-Ca were calculated by collecting water samples from these thermal sources and analyzing the physicochemical parameters at the Laboratory of Geochemical Analysis of Waters (LAGE/IRGM) in Nkolbisson. The calculations indicate that the Baré-Bakem locality exhibits temperatures ranging from 51 to 90°C for near-surface anomalies and temperatures ranging from 283 to 300°C for deeper anomalies. These geothermal resources possess high energy potential suitable for electricity production.
Marie Diane Marquise Ngono Mveng, Philémon Zo’o Zame, Joël Fabrice Nyemb Bayamack, Dieudonné Bisso, Joseph Quentin Yene Atangana
Discover Applied Sciences
Abstract Searching for borrow pits often used during civil engineering constructions is an important step that requires a lot of time and money. The nature of the parent rock, climate, topography, vegetation and time influence the formation of lateritic gravels with different geotechnical properties within the same region. The present study aims at finding the spatial variability of geotechnical parameters of lateritic gravels from two different deposits using a variogram and statistical analysis. Out of 122 lateritic gravel samples collected, 69 were from underdeveloped lithic ferrallitic soils (LFS) and 53 from under developed non-lithic ferrallitic soils (NLFS). The mean values of the coefficient of variation (CV) shows that the geotechnical parameters of LFS-derived lateritic gravels are more dispersed than those developed on NLFS. The fines content, plasticity index (PI) and Californian bearing ratio (CBR) variograms observed mainly in the North and NNE parts of the study area, suggest that, the lateritic gravels in this area have average to good geotechnical characteristics. The principal component analysis (PCA) indicates that the CBR and the maximum dry density (MDD) are inversely related to the optimum moisture content (OMC). The discriminant factor analysis (DFA) coupled to the ascending hierarchical classification (AHC) shows three families of lateritic gravels: (1) class 1/3, lateritic gravels characterized by MDD, CBR, consistency index (CI), gravels content, and plastic limit (PL); (2) class 2/3, lateritic gravels characterized by fines content, and maximum grain diameter (D max ) and, (3) class 3/3, lateritic gravels characterized by OMC, liquid limit (LL), PI, PL, and fines content, that fit for road construction.
Samuel Erick Meyomesse, Serge Parfait Koah Na Lebogo, Dieudonné Bisso, Philémon Zo’o Zame
SN Applied Sciences
Abstract Road failure catastrophes have increased in frequency in the West Cameroon area. The collapsed soil characteristics that contribute to these phenomena in Bafoussam have been investigated using the geophysical investigation combined with geotechnical tests. The result of electrical resistivity tomography shows water conditions and heterogeneity of road foundation materials: resistivity values higher than 200 Ωm indicate dry materials, values between 30 and 200 Ωm define wet materials, and values lower than 30 Ωm indicate the very wet or water-saturated materials. These water-saturated materials can therefore move, bounded by a sliding surface of high-resistivity materials. Geotechnical properties analysis shows that these materials are clayey-sensitive water (64% clay fraction; A-7-6), very plastic (liquid limit: 46–63% plasticity limit: 29–39%), compressible, with high porosity (e > 0.8), low shear strength, and high friction angle (24–37°). The quality of foundation materials associated with high slopes (> 40°) and heavy rainfall in wet seasons (July–October) means that seepage water is the main factor responsible for the mass movement observed on the road of Western Cameroon. The construction or rehabilitation of these roads should be carried out in compliance with the natural conditions of the project site. Article highlights - 2D Electrical Resistivity Tomography method is able to determine the nature, subsurface structure and water conditions of road foundation soils. - Geotechnical test can be used to define the physical and mechanical properties of road foundation soils. - These two techniques complement each other to understand the mass movement observed on two sections of road failures caused by seepage water.
Zakari Arétouyap, William Assatsé Teikeu, Sandra Céleste Tchato, Franck Eitel Kemgang Ghomsi, J. K. Domra, Dieudonné Bisso and 2 more
International Journal of Energy and Water Resources
Christelle R. Magnekou Takamte, Sylvestre Martial Ntomba, Lise C. Okomo Atouba, Dieudonné Bisso, Joseph Mvondo Ondoa
Environmental Earth Sciences
Zakari Arétouyap, Dieudonné Bisso, William Teikeu Assatsé, Janvier Domra Kana, Franck Eitel Kemgang Ghomsi, Robert Nouayou and 2 more
Environmental Earth Sciences
Sylvestre Martial Ntomba, Christelle R. Magnekou Takamte, Dieudonné Bisso, Joseph Mvondo Ondoa
Engineering Geology
This chapter mainly focuses on engineering geology for dam construction from the Memve’ele region in Cameroon. Here, it deals with geotechnical and geological proprieties of both construction and dam foundation materials. This study is done at the aim to ensure that these materials need to be improved and how they have been used during dam construction. Field investigations, borehole information, density and seismic velocity measurements have been used, and results indicate that soil deposits have slightly clay content, mechanically well for dam construction and display a weak thickness layer particularly on the dam site. These conditions suggest that soil materials can be used as construction (cushion, transition layers, etc.) and foundation materials after few amendments. Ntem Formations appear weathered and fractured sometimes, though their mechanical behaviors display a good character for civil applications. However, engineering processes have been used to improve it by GIN (Grouting Intensity Number) methods. These formations have been used as construction (rip rap crushing aggregate, etc.) and dam foundation materials. Thus, this chapter contributes to highlight materials and dam foundation conditions which are crucial criteria encountered in the dam with emphasis on both theoretical study and practical application during dam construction.
Sylvestre Martial Ntomba, Dieudonné Bisso, Rufine C. Magnekou Takamte, François Ndong Bidzang, Eric José Messi Ottou, Joseph Mvondo Ondoa
Data in Brief
Structural data, meso‑ and micro-photographics were collected from Archean basement of the Memve'ele area (Ntem Complex, southwestern Cameroon). The analyses were acquired using field and laboratory investigations. Meso-photographics were obtained by a camera Canon SX160 IS, 16X digital zoom, HD 16.0 Mega pixels. Micro-photographics were carried out by electronic microscope Olympus BX60 type with a camera and entire thin section picture scan. Structural data were acquired by a topochaix compass type and stereographic data were obtained by a stereonet program. The data presented in this paper are further interpreted and discussed in the Ntomba et al., 2020 [1].
Sylvestre Martial Ntomba, Dieudonné Bisso, Rufine C. Magnekou Takamte, François Ndong Bidzang, Eric José Messi Ottou, Joseph Mvondo Ondoa
Journal of Structural Geology
Zakari Arétouyap, Dieudonné Bisso, Philippe Njandjock Nouck, Jamal Asfahani
Advances in Science, Technology & Innovation/Advances in science, technology & innovation
Zakari Arétouyap, Dieudonné Bisso, Jorelle Larissa Méli’i, Philippe Njandjock Nouck, André Njoya, Jamal Asfahani
Geofísica Internacional
The present article aims at determining hydraulic parameters of the Pan-African aquifer in the region of Adamawa-Cameroon, namely the transmissivity (T) and the hydraulic conductivity (K). For this, fifty vertical electrical soundings (VESs),including 14 performed near existing boreholes with known values of water resistivity, have been conducted in the region using the Terrameter ABEMSAS-1000 with a spacing of current electrodes (AB) varying from 2 to 600 m.The curve matching technique is used to set structural parameters then, an inverse technique algorithm fits both theoretical and field curves for each experimental. The transverse resistance TR and the transmissivity T for the interpreted 14 VES are computed, then used to establish two relationships: one between the modified transverse resistance (MTR) andthe transverse resistance (TR) and another between MTR and the transmissivity (T).This enabled to compute MTR (ranged from 1526 to 28209 ?.m² with an average of 7873 ?.m²),TR (ranged from 24 to 31350 ?.m² with an average of 7476 ?.m²), T (ranged from 4 to 17.4 m²/day with an average of 7.23 m²/day) and K (ranged from 0.07 to 0.74 m/day with an average of 0.31 m/day) values in the whole region. The approach used for this purpose is effective and exportable to other Pan-African regions in the world.
Zakari Arétouyap, Dieudonné Bisso, Philippe Njandjock Nouck, L. E. Amougou Menkpa, Jamal Asfahani
Natural Resources Research
Jeannot F. Goussi Ngalamo, Mohamed Sobh, Dieudonné Bisso, Mohamed G. Abdelsalam, Estella A. Atekwana, Georges Emmanuel Ekodeck
Tectonophysics
Njingti-Nfor, Owona Angue Marie Louise, Kue Petou Rokis Malquaire, Dieudonné Bisso, Lando Tsakou Julyo Achille
Open Journal of Geology
Audiomagnetotelluric data were acquired for 10 sounding stations in open fields and roads along the main highways from Campo to Ma’an in Cameroon. An application of the coefficients of anisotropy was used to determine the tectonic settings and the nature of the contacts between the sedimentary formation of the Kribi-Campo basin and the cratonic Ntem Complex. The results of this study show that apart from the sedimentary formation, the metamorphic formation in this area comprises two metamorphic blocks: a regional metamorphic block which might be igneous or granitic in nature and composition and seem to be Precambrian and plutonic in origin and a contact or transitional metamorphic block, which might represent schist or gneiss rocks. The contact or transitional metamorphic block might be as a result of a long period of contact between regional metamorphic rocks and rocks of sedimentary formation. These contact/transitional metamorphic rocks which are found sandwiched between rocks of sedimentary formation and rocks of the regional metamorphic block and at varied depths confirm the existence of vertical and sub-vertical contacts between the Kribi-Campo basin and the cratonic Ntem complex. Two types of rock contacts have been identified: a sedimentary-schist contact which is found at the boundary between the sedimentary formation and the transitional metamorphic block and a schist-granite contact between the transitional and regional metamorphic blocks. Two main formations: a sedimentary formation, which is found in the Kribi-Campo sub-basin and the Ntem River bed and its flood plains and the metamorphic formation which includes both the transitional and regional metamorphic rocks have also been identified in the area of study. Subsurface rocks and rock materials have been observed to be highly resistive and occupying almost the entire subsurface in the area of study confirming the high vertical tectonic stability of the Ntem Complex even at contact with the sedimentary Kribi-Campo basin.
Owona Angue Marie Louise Clotilde, Assembe Stéphane Patrick, Njingti Nfor, Ngoh Jean Daniel, Ndougsa Mbarga Theophile, Kue Petou Rokis and 1 more
International Journal of Geosciences
With the aim to produce a detailed structural map and then enhance the geological information of the south-western Cameroon, a field gravity study is carried out in the Kribi-Campo-Ma’an area (SW Cameroon). This study area is assumed to undergo pending active tectonics as witnessed by several earthquakes [1]. Besides, the area has been affected by some shears that gave rise to many major faults including the Kribi-Campo Fault (KCF). This N-S lineament is an active fault corresponding to the NW margin of the CC [2] [3] and related to the development of the Kribi-Campo basin. The gravity data analysis enables to highlight many deeply-seated structural features trending in the NE, NNE, N-S, NNW, NW and E-W directions in this region. The NW-SE trend is more strongly developed than the other identified trends and could have deeply affected the major NNE structure. The NNE-SSW to N-S fractures and faults which are local relays of the Kribi-Campo fault are related to the Kribi shear zone. The fairly good clustering observed on local maxima of the horizontal gradient magnitude enables to suggest that the contacts outlined have vertical to subvertical dips. However, a probable interpretation of these features is that they are vertical to subvertical faults which follow the aforementioned directions. The location of the study area in the gulf of Guinea suggests that it sustains tectonics related both to the equatorial and the south Atlantic oceans opening.
Zakari Arétouyap, Njandjock Nouck Philippe, Dieudonné Bisso, Robert Nouayou, Lengue Beatrice, Lepatio Tchieg Steve Alain
Journal of Applied Sciences
T. Ndougsa-Mbarga, Dieudonné Bisso, Arsène Meying
In monitoring the Monatele-Sa’a earthquake area, audiomagnetotelluric investigation was carried out using a scalar instrument with a frequency range from 4.1 Hz to 2300 Hz. Data have been collected in the Ntui-Sa’a area near Monatele, along a profile containing seven (07) stations directed N-S, covering approximately a distance of 16.5 km. This profile crosses the Sanaga River which seems to be parallel to a buried big fault which shows no indication on the surface. The validation of the measured resistivity and calculated phase data set is done by the application of dimensionality. The interpretation of data using 2D inversion imaging of the subsurface has lead to the confirmation of two major discontinuities: The Sanaga fault oriented SSW-NNE, covered by a thick layer of alluvial deposit in the Elang III area. This fault is bisected to a lateral fracture between Nkolessono and Elang III. The fault network in Biakoa-Goura intersected the Sanaga fault is characterised by secondary faults in Biakoa and Talba. The presence of a fault network traversing the Sanaga fault shows that the study area belongs to the major tectonic accident area known as the Cameroon Central shear zone (CCSZ). The tectonic node relaxation of the Biakoa-Goura seems to be the origin of the February 2005 earthquake in Monatele and Yaounde northern areas. Department of Physics, Advanced Teacher’s Training College, University of Yaounde I, P.O. Box 47, Yaounde Cameroon Department of Physics, Faculty of Science, University of Yaounde I, P.O. Box 812, Yaounde Cameroon. Department of Earth Sciences, Faculty of Science, University of Yaounde I, P.O. Box 812, Yaounde Cameroon. 4 Geology and Mining Exploitation School, University of Ngaoundere, P.O. Box 454, Ngaoundere, Cameroon. 5 Department of Physics, Faculty of Science, University of Yaounde I, P.O. Box 812, Yaounde Cameroon. 108 T. Ndougsa-Mbarga et al. The interpretation revealed that quartzite, gneiss and migmatite are in discordance on a basement composed of granite.
Nouck Philippe Njandjock, Valentin Oyoa, Mbarga Théophile Ndougsa, Dieudonné Bisso
Zenodo (CERN European Organization for Nuclear Research)
In this work, a new informatics program in ‘C++’ language for the separation of the regional and the residual anomaly is presented. The proposed approach lies on the limits observed in the former code of the potential data processing by the least square method (POLYFIT in FORTRAN 77(Radhakrisna et al. 1990), GMSEP. PAS in PASCAL (Njandjock et al. 2003). In order to make, it has established an algorithm thanks to a mathematical analysis that takes into account all parameters that the least square method implies. The validation of this program has been enabled by the comparison of its results with those of the former codes. The improvements on the treatment of a very big number of data and a separation at a high degree have been put in evidence by the gravimetric data processing of the zone of Yagoua at north Cameroon and with the same opportunity, it has been observed that these improvements permit a more pushed analysis of the structure with the determination of the features; more deep, least deep and those that spread of depths to surface.
H. L. Ekoro Nkoungou, Philippe Njandjock Nouck, Dieudonné Bisso, Stéphane Patrick Assembe, Eliézer Manguelle Dicoum
Journal of Water Resource and Protection
This article aims to localise aquifer and to estimate hydraulic parameters such as transmissivity and tranverse resistance in the Memve Ele dam site (26.35 km2) in South-Cameroon region, using audiomagnetotelluric (AMT) method. For this purpose, resistivity data are collected at twenty-two measurement stations distributed along two perpendicular profiles in the study area. The sounding curves of phase and impedance are modelled and interpreted. The geological models and geoelectrical sections are also provided. The transverse resistivity and transmissivity field maps are plotted. The audiomagnetotellurics insights have been compared with boreholes. All these results allow us to localise the area which may be suitable to set up monitoring wells.
T. Ndougsa-Mbarga, Arsène Meying, Dieudonné Bisso, Donatus Yufenyiu Layu, Kewal Krishan Sharma, Eliézer Manguelle-Dicoum
An Audio-Magnetotelluric (A.M.T) study is carried out in the Messamena/Abong-Mbang area in Cameroon. It consists of two measurement profiles S-N. The A.M.T data sets are collected using a resistivity meter with frequencies ranging from 4.1 Hz to 2300 Hz. The frequency range used has permitted to reach some important depths because of high resistivity values of the metamorphic rocks. A 1D linearized inversion and 2D modelling of data led to attain a granitic basement at 9 km on one hand, and to put in evidence an important buried fault structure at Abong-Mbang in another hand. From a 2D modelling of pseudo-sections of resistivity and phase, a system of folds has been discovered at Messamena. The tectonic structures put in evidence in the Messamena/Abong-Mbang area are perfectly linked to the collision between the Pan-African Belt and the Congo Craton. The pseudo sections of phase for the two profiles permitted to propose two geological models of rock layers distribution.
Serge Parfait Koah Na Lebogo, Philémon Zo’o Zame, Achille Basile Anaba Onana, Franck Stell Kameni, Harold Gwet, Dieudonné Bisso
Discover Geoscience
Poor drainage conditions can lead to soil erosion and water infiltration, potentially compromising the stability of nearby buildings. This study aims to identify and characterize zones of rising groundwater at a construction site in southeastern Bangui, Central African Republic. The objective is to evaluate the potential impact of these zones on foundation stability and to guide the design of effective drainage systems. Electrical resistivity tomography (ERT) was employed as the primary investigative method, using a Schlumberger array with 2-meter electrode spacing. This geophysical technique was selected due to its proven effectiveness in delineating subsurface structures and assessing groundwater flow patterns in complex geological settings. The ERT survey revealed three distinct layers: (i) weathered bedrock (236–750 Ω·m); (ii) fissured bedrock (750–2,400 Ω·m); and (iii) fresh bedrock (> 2,400 Ω·m). Zones of low resistivity (less than 236 Ω·m) indicated saturated areas likely associated with groundwater accumulation. Two aquifer systems were identified: a shallow weathered bedrock aquifer (2–4 m deep) and a deeper fissured aquifer. The shallow aquifers extend laterally 3–10 m, with a water table depth of 1.5–3 m. They lack hydraulic connectivity with the deeper system, which likely contributes to the observed rise in groundwater levels. These findings underscore the importance of detailed hydrogeophysical surveys in construction planning. Rising groundwater, resulting from isolated aquifer systems, can threaten the structural integrity of foundations. The results inform the design of more resilient drainage infrastructure and highlight the need for ongoing hydrogeological monitoring, particularly of piezometric levels and flow dynamics, to ensure the site’s long-term . ✓ Electrical resistivity tomography reveals hidden groundwater risks at construction sites. ✓ Two disconnected aquifers can contribute to rising groundwater levels, which can impact the stability of infrastructure. ✓ A multi-layered aquifer system influences drainage system design and soil behavior.
Stephane Landry Kwega Ghomsi, Dieudonné Bisso, Sylvestre Ganno, Luan Thanh Pham, Róbert Tenzer, Franck Eitel Kemgang Ghomsi
Journal of African Earth Sciences
Southwest Cameroon has long lacked detailed geological data, prompting an investigation into its geological and tectonic features through innovative edge detection techniques applied to gravity data. We employed various methods, including the Analytical Signal (AS), Tilt Angle (TDR), Total Horizontal Gradient of the Tilt Angle (TDR_THDR), and the Logistic Filter (IL) to delineate geological features that manifest as lineaments and contacts on gravity anomaly maps. Main findings of this study involve identification of key tectonic boundaries, notably the Kribi-Campo faults (KCF) and the Ebolowa pseudo-karstic circular network, the latter being mapped for the first time. This work reveals the continuity of the Ebolowa network and integrates connections such as the Mbilibekon and Mfuda caves, enhancing our understanding of the region's geological evolution. Additionally, we detailed the north-south extension of the KCF, which extends into both oceanic and terrestrial domains, aligning with the eastern margin of the Congo Craton. This finding suggests the fault system's role as a transition between the stable cratonic core and the dynamic mobile belts, necessitating a re-evaluation of regional tectonic models. To support our edge detection interpretations, we estimated Moho depths using gravity and seismic data, finding a Moho depth range between 34.5 km to 45.9 km, correlating with significant faulting and sedimentary features. This research enhances the understanding of subsurface structures in Southwestern Cameroon and provides a robust foundation for future geological and geophysical studies, emphasizing the critical interplay between surface and subsurface processes.
Jean Lucien, Mbida Yem, Armel Zacharie Ekoa Bessa, Thomas Tamo Tatiétsé, Dieudonné Bisso, Abdelaziz Mridekh and 2 more
Arabian Journal of Geosciences
Abstract The empirical GIN (grouting intensity number) method is one of the most popular methods for structural stabilization and is increasingly used in many projects. The concept of this method is to limit the combination of pressure and volume injected to a specific grouting intensity number in order to control the energy induced in the rock fractures and to avoid heaving. In order to ensure the water tightness of the foundation of the Memve’ele hydroelectric dam, the treatment by the GIN method was implemented. The protocol implemented consisted to carry out a veil of injection drilling, consolidation, and control of effective treatment on each geotechnical hazard zone. Thus, 1240 injection boreholes were opened over a total length of 1600 m, i.e.: 613 pre-treatment boreholes and 627 consolidation boreholes. The results of the monitoring tests show that the 0.7 cement grouting treatment contributed to a reduction in crack permeability to less than 5 Lu (Lugeon units), a reduction of over 94%. This confinement of the rock was confirmed by geophysical imagery whose signature at the fractured interval varied after treatment. Geophysical and geohydrological characterization through permeability testing and electrical tomography revealed the existence of highly permeable discontinuity zones (over 90 Lu) below the bedrock surface, up to 15 m wide. Notwithstanding the volume of drilling carried out, the results obtained support the use of the GIN method in the stabilization of foundations of structures in the granite-gneissic basement zone.
Serge Parfait Koah Na Lebogo, Dieudonné Bisso, Mike-Franck Mienlam Essi, Cécile Olive Mbesse
Research Square
Abstract The present study aims to establish the stratigraphic architecture in order to understand the depositional history during the Paleocene- Early Eocene interval in the Douala Onshore Basin. The sequence stratigraphic analysis from gamma-ray logs and well cuttings was used to define stratigraphic surfaces and systems tracts based on the depositional sequence model. The results obtained show that the Paleocene-Early Eocene interval could be subdivided into three lithostratigraphic units (Unit 1, Unit 2, and Unit 3) of Middle Paleocene - Late Paleocene, Late Paleocene - Early Eocene, and Early Eocene age respectively. The sequence stratigraphic interpretation revealed three major stratigraphic surfaces : the sequence boundary (SB1) of the Middle Paleocene top, the transgressive surface (TS2) of the Late Paleocene, and the maximum flooding surface (MFS2) of the Early Eocene. The first highstand systems tracts (HST1) of the Middle Paleocene, the lowstand systems tract (LST2) of the Late Paleocene, the transgressive systems tract (TST2) of the Late Paleocene to Early Eocene, and the second highstand systems tracts (HST2) of the Early Eocene are the depositional sequences observed. The Paleocene-Eocene interval is therefore globally prograding, interrupted by a short transgressive episode of Late Paleocene to Early-Eocene age. Three cycles of base-level have been identified: the first cycle of base-level fall dated Middle Paleocene, the second cycle of rapid base-level rise which occurred between Late Paleocene to Early Eocene, and the third cycle of base-level fall dated Early Eocene. This observation confirms that the main factor which influenced the depositional history of Paleocene- Early Eocene succession in the Douala Onshore Basin was the eustatic sea-level changes due to the Cenozoic post-rift subsidence of the West African margin.
Daniel Eutyche Mbadjoun Wapet, Salomé Ndjakomo Essiane, R. Wamkeue, Dieudonné Bisso, Patrick Juvet Gnetchejo
Energy Reports
Optimizing the production of electrical energy through the efficient management of reservoirs is one of the major concerns in power supply. Then, optimization methods have been employed to solve the problem of service continuity in a generation. Many reservoir management issues are indeed addressed without achieving a desired solution in line with demand. The main motivation for state-of-the-art technology is to develop robust and intelligent methods that enable strict compliance with production restrictions while meeting energy demand. This paper follows this perspective by proposing the water supply and hydroelectric production through a hybrid method combining the differential evolution and two constraints processing treatments (TCPT). The interest of the constraint method using here, including its superiority of feasible solutions (SF) and auto-adaptative penalty (AP) is its ability to overcome premature convergence and to obtain very accuracy near optimal solutions. AP technique improve by its ability process through tedious trial and error methods to select the best penalty coefficient during implementation. SF, for its part, is a technique for comparing unrealistic solutions on the basis of the violation of global constraint aimed at pushing unrealistic solutions towards the feasible region, while comparing two workable solutions on objective value improves the overall solution. To compare the performance of the proposed hybrid method of optimization with the SF and AP techniques as a constraint method, a series of experiments was firstly carried out using 25 well know benchmark functions. The obtained results as opposed to the current hybrid method such as TCPT-PSO, TCPT-ABC and TCPT-GA have exhibited the method’s superiority. Based on these performances, we employed the proposed hybrid method to manage the water supply and hydroelectric production of the Memve’ele reservoir. The application on the management of Memve’ele Reservoir demonstrates its accuracy in providing a near-optimal solution on the order of 99.7% for 1945s, 1985s and 1988s of demand during the seven hydrological years of the Ntem Valley with real mean square error (RMSE) in order of 10−7 for water supply and hundredth for hydropower reservoir operation.
Daniel Eutyche Mbadjoun Wapet, Salomé Ndjakomo Essiane, R. Wamkeue, Dieudonné Bisso, Patrick Juvet Gnetchejo, Mohit Bajaj
Journal of Applied Water Engineering and Research
This article describes the evaluation performance of two constraint processing treatments (TCPT) techniques: the advantages of feasible (SF) and adaptive penalty (SP) solutions in combination with differential evolution (DE). Our approach is tested on Dez reservoir data related to water supply and hydropower operation to evaluate the accuracy of our approach. The results of the simulations on water supply and hydroelectric exploitation with spillway parameters forecast better prospects for the water resources of Ntem water flow. Indeed, to demonstrate the robustness of our approach, we did a simulation of the test functions to assess their potential. Then, we did a comparative analysis of our approach with other algorithms combined with the constraint treatment method. The quality of the results obtained by TCPTDE is much better in determining optimal solutions than the genetic algorithms, the swarm of particles, the colony of bees and the Drone Squadron Optimization (DSO) hybridized with TCPT.
Sylvestre Martial Ntomba, Dieudonné Bisso, Lise Okomo Atouba, Rufine christelle Magnekou Takamte, Sylvie Durande Djikam Patipe, Joseph Mvondo Ondoa
Research Square
Abstract This paper presents the results of engineering investigations used to select a best design for the Memve’ele dam. The selection of Memve’ele dam type has been based on consideration of physical factors such as topography, climate, availability of construction material, geology, geotechnical and foundation conditions and the selection of optima alternative between three dam types. According to these factors, Memve’ele valley is very wide and situated in the warm climate zone with dry and rainy seasons favorable to embankment type dam; the geology reveals very good conditions with Ntem formations and residual deposits as foundation materials and the dam site is not influenced by earthquake; this behavior is confirmed by geotechnical data and further indicates that this site is favorable to a composite dam type (embankment and concrete dams or connecting concrete structures) and the construction materials found within or near the dam site are suitable for usage. These characteristics have contributed retaining three dam types. The alternative of these three dams is a composite dam type option including homogeneous earth dam and rock fill dam with central core link by concrete structures. Engineering geological map and general layout of Memve’ele’s dam highlight the important role plays by engineers. The main dam that is observed actually in the Memve’ele dam site is composed from left to right of left connecting dam section, flushing sluice, main spillway section, riverbed dam section, auxiliary spillway section and right bank dam section.
Zakari Arétouyap, Franck Eitel G Kemgang, Janvier Domra Kana, Dieudonné Bisso, Philippe Nouck Njandjock
Natural Hazards
Dieudonné Bisso, Sylvestre Martial Ntomba, Ruth C. Mengbwa, Rufine C. Magnekou Takamte, Joseph Mvondo Ondoa
Geotechnical and Geological Engineering
Joëlle Sihon, Jean‐Jacques Braun, Stéphane Audry, Jérôme Viers, Yves Auda, Jules Rémy Ndam Ngoupayou and 3 more
EGU General Assembly Conference Abstracts
Dieudonné Bisso, Zakari Arétouyap, Georges Nshagali Biringanine, Philippe Njandjock Nouck, Jamal Asfahani
Advances in Science, Technology & Innovation/Advances in science, technology & innovation
Njingti-Nfor, Owona Angue Marie Louise Clotilde, Kue Petou Rokis Malquaire, Dieudonné Bisso, Piameu Kwagag Jöel
International Journal of Geosciences
The magnetotelluric prospection method has been widely used in Cameroon not only as a reconnaissance method for geophysical investigations but also to determine the nature of the subsurface and the structural settings of the various geological formations in the country that resulted from the global geo-tectonic movements. The present study is aimed at employing the magnetotelluric method to provide evidence on major tectonic dislocations which might have led to the presence of plutonic intrusions in the cratonic structure of the Ntem Complex as well as determining the nature of the contact between the sedimentary Campo Basin and the metamorphic cratonic Ntem Complex. The analyses and interpretations of iso-resistivity maps and geoelectric sections from magnetotelluric data has enabled us to show that tectonic forces at contact between the sedimentary Campo Basin and the metamorphic Ntem Complex were of three different categories: gravity gliding, magmatic upwelling and lateral compressions. The results of the action of these forces were the development of vertical and sub-vertical faulting systems at Craton-Sedimentary Basin contact and subsidence of overburden that appears to have also paved the way for the setting-up of the Ntem River bed and its flood plains. This river bed and its flood plains have been characterized as having a sedimentary deposit depth of 500 m and width of 20 km. Meanwhile, the deep-seated contact faulting systems within the two identified formations have varied fault magnitudes with a maximum of 60 km. The relatively high apparently resistivity values (up to1.0 kΩ•m) for the sedimentary and the very high values for the metamorphic formations (up to and above 10.0 kΩ•m) suggest that the whole area is at present relatively geo-tectonically stable.
Zakari Arétouyap, Dieudonné Bisso, Philippe Njandjock Nouck, Shey Jones Yembe, Diab Ahmad Diab
Journal of Environmental Management
Jeannot F. Goussi Ngalamo, Dieudonné Bisso, Mohamed G. Abdelsalam, Estella A. Atekwana, Andrew Katumwehe, Georges Emmanuel Ekodeck
Journal of African Earth Sciences
Dieudonné Bisso, Mbida Yem, Serge Parfait Koah Na Lebogo, Joseph Mvondo Ondoa, Carine Tsoungui
Le bassin de Garoua est une structure d’allongement N90 a N115. Il est constitue de 1000 a 4000 m d’epaisseur de sediments donc l’âge varie de l’Aptien au Maastrichtien. Ces depots sedimentaires sont traverses par des venues volcaniques (basaltes ou trachytes) d’âge Priabonien. Dans le cadre de cette etude, l’analyse morphostructurale a partir des MNT de 30 m de resolution spatiale montre que les failles coulissantes N135°E a N250°E, ont influencees l’evolution recente du bassin de Garoua. L’examen du developpement global de ce systeme met evidence deux phases de deformation post sedimentaire. A savoir une phase de tectonique des blocs (decrochement) fin cretace et une phase d’inversion (transpression) Mio-pliocene. Le jeu inverse des failles N90°E a N115°E initialement normales aurait provoque durant cette derniere phase, la surrection du bassin, avec pour consequence l’erosion des depots tertiaires.
Sylvestre Martial Ntomba, François Ndong Bidzang, José Eric Messi Ottou, François Jeannot Goussi Ngalamo, Dieudonné Bisso, Christelle R. Magnekou Takamte and 1 more
Journal of African Earth Sciences
Jorelle Larissa Méli’i, Dieudonné Bisso, Philippe Nouck Njandjock, Théophile Ndougsa Mbarga, Alain Francois Banga, Eliezer Manguelle-
Journal of Applied Sciences
William Assatsé Teikeu, Philippe Nouck Njandjock, Dieudonné Bisso, Quentin Yene Atangana, Jean-Paul Sep Nlomgan
Journal of Water Resource and Protection
Detailed local geological and hydrogeophysical investigations were carried out for the aquifer in Yaoundé, Cameroon to delineate the architecture of different subsurface geological horizons using lithologs and generated vertical electrical sounding (VES) data. An attempt has also been made to estimate aquifer transmissivity from resistivity data. The transmissivity of the uncon?ned aquifer was computed by determining the Dar-Zarrouk parameters (longitudinal unit conductance and transverse unit resistance) and were compared with the actual field transmissivity. The results showed a direct relation between aquifer transmissivity and transverse resistance. The relationship established has therefore, been generalized in the study area in order to evaluate hydraulic conductivity and transmissivity at all the points where geoelectrical measurements have been carried out. This generalization allows one to derive maps of the product Kσ and transmissivity in the study area based on geoelectrical measurements. These maps are important in future modelling processes oriented towards better exploitation of the aquifers.
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