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ISSN  2096-3955

CN  10-1502/P

Citation: Kamto, P. G., Adiang, C. M., Nguiya, S., Kamguia, J. and Yap, L. (2020). Refinement of Bouguer anomalies derived from the EGM2008 model, impact on gravimetric signatures in mountainous region: Case of Cameroon Volcanic Line, Central Africa. Earth Planet. Phys., 4(6), 639–650doi: 10.26464/epp2020065

2020, 4(6): 639-650. doi: 10.26464/epp2020065


Refinement of Bouguer anomalies derived from the EGM2008 model, impact on gravimetric signatures in mountainous region: Case of Cameroon Volcanic Line, Central Africa


Geodesy Research Laboratory, National Institute of Cartography (NIC), Yaounde, Cameroon


Department of Physics, Faculty of Science, University of Yaounde I, Cameroon


Laboratory E3M, Faculty of Industrial Engineering, University of Douala, Cameroon


Department of Physics, Faculty of Science, University of Douala, Cameroon

Corresponding author: Paul Gautier Kamto,

Received Date: 2020-05-04
Web Publishing Date: 2020-11-09

Global geopotential models have not included the very high frequencies of the Earth’s external gravity field. This is called omission error. This omission error becomes more important in mountainous areas (areas with highly variable topography). The work reported here consists in reducing the omission error in measurements of Bouguer gravity anomalies, by refining the global geopotential model EGM2008 using the spectral enhancement method. This method consists in computing the residual terrain effects and then coupling them to the gravimetric signal of the global geopotential model. To compute the residual terrain effects, we used the Residual Terrain Model (RTM) technique. To refine it required a reference surface (ETOPO1) developed up to degree 2190 (the maximum degree of the EGM2008 model) and a detailed elevation model (AW3D30). Computation was performed with the TC program of the GRAVSOFT package. The topography of the study area was assumed to have a constant density of 2670 kg/m3. For the inner and outer zones, the respective integration radii of 10 km and 200 km have been chosen. We obtained very important RTM values ranging from −53.59 to 34.79 mGal. These values were added to the gravity anomalies grid of the EGM2008 model to improve accuracy at high frequencies. On a part of the Cameroon Volcanic Line and its surroundings (mountainous area), we made a comparison between the residual Bouguer anomalies before and after refinement. We report differences ranging from −37.40 to 26.40 mGal. We conclude that the impact of omission error on gravimetric signatures is observed especially in areas with high variable topography, such as on the Cameroon Volcanic Line and around the localities of Takamanda, Essu, Dumbo, and Ngambe. This finding illustrates the great influence that topography has on accurate measurement of these gravity anomalies, and thus why topography must be taken into account. We can conclude that in preparing a global geopotential model, a high resolution DTM must be used to decrease the omission error: the degree of expansion has to increase in order to take the higher frequencies into account. The refined Bouguer anomalies grid presented here can be used in addition to terrestrial gravity anomalies in the study area, especially in mountainous areas where gravimetric data are very sparse or non-existent.

Key words: residual Terrain Model, EGM2008, Omission error, refined Bouguer anomalies, mountainous area

Abd-Elmotaal, H. A., Seitz, K., Kühtreiber, N., and Heck, B. (2018). AFRGDB_V2.0: the gravity database for the geoid determination in Africa. In Proceedings of the IAG Scientific Assembly (pp. 61-70). Kobe: Springer.

Adighije, C. I. (1981). A gravity Interpretation of the Benue Trough, Nigeria. Tectonophysics, 79(1-2), 109–128.

Amante, C. and Eakins, B. W. (2008). ETOPO1 1 Arc-Minute Global Relief Model: Procedures, Data Sources and Analysis. National Geophysical Data Center, NESDIS, NOAA, U.S. Department of Commerce, Boulder, CO.222

Apeh, O. I., Moka, E. C., Uzodinma, V. N., and Ebinne, E. S. (2019). Refinement and quantification of terrain-induced effects on global gravity data. Int. J. Geosci., 10(5), 513–526.

Balmino, G., Vales, N., Bonvalot, S., and Briais, A. (2012). Spherical harmonic modelling to ultra-high degree of Bouguer and isostatic anomalies. J. Geod., 86(7), 499–520.

Barthelmes, F. (2013). Definition of Functionals of the Geopotential and Their Calculation from Spherical Harmonic Models: Theory and Formulas Used by the Calculation Service of the International Centre for Global Earth Models (ICGEM). Scientific Technical Report STR09/02.222

Benkhelil, J. (1986). Structure and geodynamics evolution of the intracontinental Benue Trough (Nigeria). France: University of Nice.222

Benkhelil, J. (1989). The origin and evolution of the cretaceous Benue trough (Nigeria). J. Afr. Earth Sci., 8(2-4), 251–282.

Boukeke, D. B. (1994). Structures Crustales d’Afrique Centrale Déduites des Anomalies Gravimétriques et Magnétiques: le Domaine Précambrien de la République Centrafricaine et du Sud Cameroun. France: Université de Paris Sud, 263.222

Collignon, F. (1968). Gravimétrie de Reconnaissance. Cameroun: ORSTOM, 35.222

Cratchley, C. R., Louis, P., and Ajakaiye, D. E. (1984). Geophysical and geological evidence for the Benue-Chad Basin Cretaceous Rift Valley System and its tectonic implication. J. Afr. Earth Sci., 2(2), 141–150.

Déruelle, B., Moreau, C., Nkoumbou C., Kambou, R., Lissom, J., Njonfang, E., Ghogomu, R. T., and Nono, A. (1991). The Cameroon line: a review. In A. B. Kampunzu, et al. (Eds.), Magmatism in Extensional Structural Settings. Berlin, Heidelberg: Springer, 274-327.

Déruelle, B., Ngounouno, I., and Demaiffe, D. (2007). The ‘Cameroon Hot Line’ (CHL): a unique example of active alkaline intraplate structure in both oceanic and continental lithospheres. C. R. Geosci., 339(9), 589–600.

Djomani, Y. H. P., Diament, M., and Albouy, Y. (1992). Mechanical behaviour of the lithosphere beneath the Adamawa uplift (Cameroon, West Africa) based on gravity data. J. Afr. Earth Sci., 15(1), 81–90.

Dorbath, C., Dorbath, L., Fairhead, J. D., and Stuart, G. W. (1986). A teleseismic delay time study across the Central African shear zone in the Adamawa Region of Cameroon, West Africa. Geophys. J. Roy. Astron. Soc., 86(3), 751–766.

Drewes, H., Kuglitsch, F., Adám, J., and Rózsa, S. (2016). The Geodesist’s handbook 2016. J. Geod., 90(10), 907–1205.

Elf-Serepca (1981). Service d’Exploration Carte Géologique du Bassin de Garoua.222

Fairhead, J. D., and Okereke, C. S. (1987). A regional gravity study of the West African rift system in Nigeria and Cameroon and its tectonic interpretation. Tectonophysics, 143(1-3), 141–159.

Forsberg, R., and Tscherning, C. C. (1981). The use of height data in gravity field approximation by collocation. J. Geophys. Res. Solid Earth, 86(B9), 7843–7854.

Forsberg, R. (1984). A Study of Terrain Reductions, Density Anomalies and Geophysical Inversion Methods in Gravity Field Modelling. Report 355, Department of Geodetic Science and Surveying, Ohio State University, Columbus.222

Forsberg, R. (1985). Gravity field terrain effect computations by FFT. Bull. Géodésique, 59(4), 342–360.

Forsberg, R., and Tscherning, C. C. (2008). An Overview Manual for the GRAVSOFT Geodetic Gravity Field Modelling Programs. 2nd ed. National Space Institute (DTU-Space), Denmark.222

Gèze, B. (1941). Sur les massifs volcaniques du Cameroun occidental. C. R. l’Acad. Sci., 212, 498–500.

Gruber, T. (2009). Evaluation of the EGM2008 Gravity Field by Means of GPS Levelling and Sea Surface Topography Solutions. Publication the International Association of Geodesy and International Gravity Field Service, 3–17.

Hammer, S. (1939). Terrain corrections for gravimeter stations. Geophysics, 4(3), 184–194.

Hayford, J., and Bowie, W. (1912). The effect of topography and isostatic compensation upon the intensity of gravity. Bull Amer. Geogr. Soc., 44(6), 464–465.

Hirt, C. (2010). Prediction of vertical deflections from high-degree spherical harmonic synthesis and residual terrain model data. J. Geod., 84(3), 179–190.

Hirt, C., Featherstone, W. E., and Marti, U. (2010). Combining EGM2008 and SRTM/DTM2006.0 residual terrain model data to improve quasigeoid computations in mountainous areas devoid of gravity data. J. Geod., 84(9), 557–567.

Hirt, C., Gruber, T., and Featherstone, W. E. (2011). Evaluation of the first GOCE static gravity field models using terrestrial gravity, vertical deflections and EGM2008 quasigeoid heights. J. Geod., 85(10), 723–740.

Hirt C., Kuhn, M., Claessens, S. J., Pail, R., Seitz, K., and Gruber, T. (2014). Study of the Earth's short-scale gravity field using the ERTM2160 gravity model. Comput. Geosci., 73, 71–80.

Huang, O. (2012). Terrain corrections for gravity gradiometry. Report 500, Department of Geodetic Science and Surveying, Ohio State University, Columbus.222

Ismail, Z. (2016). Détermination de l’Exactitude d’un Géoïde Gravimétrique. Paris: Paris Sciences et Lettres.222

Jekeli, C., Yanh, H. J., and Kwon, J. H. (2009). Evaluation of EGM08-Globally and Locally in South Korea. Publication the International Association of Geodesy and International Gravity Field Service, 38–49.

Kamguia, J., Tadjou, J. M., and Ngouanet, C. (2015). The mount Cameroon height determined from ground gravity data, global navigation satellite system observations and global geopotential models. Ghana J. Sci., 55, 37–49.

Kenfack, J. V., Tadjou, J. M., Kamguia, J., Tabod, C. T., and Bekoa, A. (2011). Gravity interpretation of the Cameroon Mountain (West Central Africa) based on the new and existing Bata. Int. J. Geosci., 2(4), 513–522.

Kuisseu, T. S., Lordon, A. E., Agyingi, M. C., Shandini, Y., Mbohlieu, Y. T., and Ndifor, D. B. (2018). Geometrical configuration of the Garoua Basin, North Cameroon as deduced from earth gravitational model (EGM-2008). Anu. Inst. Geociências, 41(2), 167–176.

Leaman, D. E. (1998). The gravity terrain correction-practical considerations. Explor. Geophys., 29(3-4), 467–471.

Lordon, A. E. D., Shandini, Y., Agyingi, C. M., Yossa, M. T., Kuisseu, T. S., and Ndifor, B. D. (2017). Structural interpretation of the Mamfe Basin from satellite gravity data (EGM 2008). J. Earth Sci. Geotechn. Eng., 7(4), 45–53.

Lordon, A. E. D., Yossa, T., Agyingi, C. M., Shandini, Y., and Kuisseu, T. S. (2018). Geometrical characterisation of the Mamfe Basin from the earth gravitational model (EGM 2008). Earth Sci. Res., 7(1), 94.

Marcel, J., Abate, E. J. M., Nouck, P. N., Ngatchou, H. E., Oyoa, V., Tabod, C. T., and Manguelle-Dicoum, E. (2016). Structure of the crust beneath the South Western Cameroon, from gravity data analysis. Int. J. Geosci., 7(8), 991–1008.

Maurin, J. C., and Guiraud, R. (1990). Relationships between tectonics and sedimentation in the Barremo-Aptian intracontinental basins of Northern Cameroon. J. Afr. Earth Sci., 10(1-2), 331–340.

Mbom-Abane, S. (1997). Investigation géophysique en bordure du Craton du Congo (région d’Abong-Mbang/Akonolinga, Cameroun) et implications structurales. Université de Yaoundé I.222

Ngatchou, H. E., Liu, G. Y., Tabod, C. T., Kamguia, J., Nguiya, S., Tiedeu, A., and Ke, X. P. (2014). Crustal structure beneath Cameroon from EGM2008. Geod. Geodyoam, 5(1), 1–10.

Ngounouno, I., Nkoumbou, C., and Loule, J. P. (1997). Relation entre l’évolution Tectonosédimentaire et le Magmatisme du Fossé de Garoua (Nord Cameroun). Afr. Geosci. Rev., 4, 451–460.

Nguene, F. R., Tamfu, S., Loule, J. P., Ngassa, C. (1992). Paleoenvironments of the Douala and Kribi/Campo Subbasins in Cameroon, West Africa. In R. Curnelle (Ed.), Géologie Africaine. 1er Colloque de Stratigraphie et de Paléogéographie des Bassins Sédimentaires Ouest Africains. 2ème Colloque Africain de Micropaléontologie, 6-8 Mai 1991, Libreville, Gabon. Bulletin du Centre de Recherche. Exploration–Production, Elf Aquitaine, 13, 129–139.

Nguiya, S., Pemi, M., M., Tokam, A. P., Ngatchou, H. E., and Lemotio, W. (2019). Crustal structure beneath the mount Cameroon region derived from recent gravity measurements. C. R. Geosci., 351(6), 430–440.

Nnange, J. M., Djomani, Y. H., Fairhead, J. D., and Ebinger, C. (2001). Determination of the isostatic compensation mechanism of the region of the Adamawa dome, West Central Africa using the admittance technique of gravity data. Afr. J. Sci. Technol., 1(4), 29–35.

Noutchogwe T. C., Tabod, C. T., and Manguelle-Dicoum, E. (2006). A gravity study of the crust beneath the Adamawa fault zone, west central Africa. J. Geophys. Eng., 3(1), 82–89.

Ofoegbu, C. O., and Mohan, N. L. (1990). Interpretation of aeromagnetic anomalies over part of Southeastern Nigeria using three-dimensional Hilbert Transformation. Pure Appl. Geophys., 134(1), 13–29.

Pavlis, N. K., Holmes, S. A., Kenyon, S. C., and Factor, J. K. (2008). An Earth Gravitational Model to Degree 2160: EGM2008. In General Assembly of the European Geoscience Union. Vienna.222

Pavlis, N. K., Holmes, S. A., Kenyon, S. C., and Factor, J. K. (2012). The development and evaluation of the Earth Gravitational Model 2008 (EGM2008). J. Geophys. Res. Solid Earth, 117(B4), B04406.

Radhakrishna, I. V., and Krishnamacharyulu, S. K. G. (1990). Polyfit: a fortran 77 program to fit a polynomial of any order to potential field anomalies. J. Assoc. Explor. Geophys., 11, 99–105.

Regnoult, J. M. (1986). Synthèse Géologique du Cameroun. Ministère des Mines et de l’Energie, Yaoundé, 119.222

Sampietro, D., Sona, G., and Venuti, G. (2007). Residual terrain correction on the sphere by an FFT algorithm. In 1st International Symposium of the International Gravity Field Service. Istanbul: General Command of Mapping.222

Sampietro, D., Capponi, M., Mansi, H. A., Gatti, A., Marchetti, P., and Sansò, F. (2017). Space-wise approach for airborne gravity data modelling. J. Geod., 91(5), 535–545.

Shandini, Y., Kouske, A. P., Nguiya, S., and Marcelin, M. P. (2018). Structural setting of the Koum sedimentary basin (North Cameroon) derived from EGM2008 gravity field interpretation. Contrib. Geophys. Geod., 48(4), 281–298.

Sheng, M. B., Shaw, C., Vaníček, P., Kingdon, R. W., Santos, M., and Foroughi, I. (2019). Formulation and validation of a global laterally varying topographical density model. Tectonophysics, 762, 45–60.

Tadono, T., Nagai, H., Ishida, H., Oda, F., Naito, S., Minakawa, K., and Iwamoto, H. (2016). Initial validation of the 30 m-mesh global digital surface model generated by ALOS PRISM. In International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences (pp. 157-162). Prague, Czech Republic: ISPRS.222

Takaku, J., Tadono, T., Tsutsui, K., and Ichikawa, M. (2016). Validation of ‘AW3D’ global DSM generated from ALOS PRISM. In Annals of Photogrammetry, Remote Sensing and Spatial Information Sciences (pp. 25-31). Prague, Czech Republic: ISPRS.222

Tong, L. T., and Guo, T. R. (2007). Gravity terrain effect of the seafloor topography in Taiwan. Terr. Atmos. Oceanic Sci., 18(4), 699–713.

Torge, W. (2001). Geodesy (3rd ed). Berlin: de Gruyter.222

Toteu, S. F., Michard, A., Bertrand, J. M., and Rocci, G. (1987). U–Pb dating of Precambrian rocks from northern Cameroon, Orogenic evolution and chronology of the Pan African Belt of Central Africa. Precambrian Res., 37(1), 71–87.

Toteu, S. F., Penaye, J., and Djomani, Y. P. (2004). Geodynamic evolution of the Pan African Belt in Central Africa with special reference to Cameroon. Can. J. Earth Sci., 41(1), 73–85.

Wang, J. H., and Geng, Y. (2015). Terrain correction in the gradient calculation of spontaneous potential data. Chinese J. Geophys., 58(6), 654–664.

Yahaya, S. I., and El Azzab, D. (2018). High-resolution residual terrain model and terrain corrections for gravity field modelling and geoid computation in Niger Republic. Geod. Cartogr., 44(3), 89–99.

Yap, L., Kandé, L. H., Nouayou, R., Kamguia, J., Ngouh, N. A., and Makuate, M. B. (2019). Vertical accuracy evaluation of freely available latest high-resolution (30 m) global digital elevation models over Cameroon (Central Africa) with GPS/leveling ground control points. Int. J. Dig. Earth, 12(5), 500–524.

Zaki, A., Mansi, A. H., Selim, M., Rabah, M., and El-Fiky, G. (2018). Comparison of satellite altimetric gravity and global geopotential models with shipborne gravity in the Red Sea. Mar. Geod., 41(3), 258–269.


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Refinement of Bouguer anomalies derived from the EGM2008 model, impact on gravimetric signatures in mountainous region: Case of Cameroon Volcanic Line, Central Africa

Paul Gautier Kamto, Cyrille Mezoue Adiang, Severin Nguiya, Joseph Kamguia, Loudi Yap