Analysis and interpretation of gravity data from the Aluto-Langano geothermal field of Ethiopia

Czasopismo : Acta Geophysica
Tytuł artykułu : Analysis and interpretation of gravity data from the Aluto-Langano geothermal field of Ethiopia

Autorzy :
Bogusz, J.
Centre of Applied Geomatics, Military University of Technology,,
Saibi, H.
Laboratory of Exploration Geophysics, Department of Earth Resources Engineering, Faculty of Engineering, Kyushu University, Fukuoka, Japan,,
Abstrakty : The Aluto-Langano geothermal field is located in the central southern portion of Ethiopia within the Ethiopian Rift Valley. The gravity of the area was surveyed in an attempt to delineate the subsurface structure and to better understand the relationship between the geothermal systems and the subsurface structure. The gravity data were analyzed using integrated gradient interpretation techniques, such as the Horizontal Gradient (HG), Source Edge Detection (SED), and Euler Deconvolution (ED) methods. These techniques detected many faults that were compared with the mapped faults in the surface geology. The results of the present study will lead to an improved understanding of the geothermal system in the study area and aid the future geothermal exploration of the area.

Słowa kluczowe : gravity, Aluto-Langano, geothermal field, subsurface structure, Ethiopia,
Wydawnictwo : Instytut Geofizyki PAN
Rocznik : 2012
Numer : Vol. 60, no. 2
Strony : 318 – 336
Bibliografia : Blakely, R.J., and R.W. Simpson (1986), Approximating edges of source bodies from magnetic or gravity anomalies, Geophysics 51, 7, 1494-1498, DOI: 10.1190/1.1442197.
Chernet, T., W.K. Hart, J.L. Aronson, and R.C. Walter (1998), New age constraints on the timing of volcanism and tectonism in the northern Main Ethiopian Rift–southern Afar transition zone (Ethiopia), J. Volcanol. Geoth. Res. 80, 3-4, 267-280, DOI: 10.1016/S0377-0273(97)00035-8.
Cordell, L. (1979), Gravimetric expression of graben faulting in Santa Fe Country and the Espanola Basin, New Mexico. In: R.V. Ingersoll (ed.), Guidebook to Santa Fe Country, 30th Field Conference, New Mexico Geological Survey, 59-64.
Cordell, L., and V.J.S. Grauch (1982), Mapping basement magnetization zones from aeromagnetic data in the San Juan Basin; New Mexico, Presented at the 52nd Ann. Int. Meeting, Soc. Explor. Geophys., Dallas; Abstracts and biographies, 246-247.
Cordell, L., and V.J.S. Grauch (1985), Mapping basement magnetization zones from aeromagnetic data in the San Juan Basin, New Mexico. In: W.J. Hinz (ed.), The Utility of Regional Gravity and Magnetic Anomaly Maps, Soc. Explor. Geophys., 181-197.
Corner, B., and W.A. Wilsher (1989), Structure of the Witwatersrand basin derived from interpretation of the aeromagnetic and gravity data. In: G.D. Garland (ed.), Proc. Exploration ’87, Third Decennial Int. Conf. Geophysical and Geochemical Exploration for Minerals and Groundwater, Ontario Geol. Survey, Special 3, 532-546.
Di Paola, G.M. (1972), The Ethiopian Rift Valley (between 7°00′ and 8°40′ lat. North), Bull. Volcanol. 36, 4, 517-560, DOI: 10.1007/BF02599823.
Electroconsult ELC (1986), Exploitation of Aluto-Langano geothermal resources, Feasibility Report, Milano, Italy.
Endeshaw, A. (1988), Current status (1987) of geothermal exploration in Ethiopia, Geothermics 17, 2-3, 477-488, DOI: 10.1016/0375-6505(88)90077-6.
Fairhead, J.D., K.J. Bennett, D.R.H. Gordon, and D. Huang (1994), Euler: Beyond the “Black Box”, SEG Expanded Abstr. 13, 422-424, DOI: 10.1190/1.1932113.
FitzGerald, D., A. Reid, and P. McInerney (2004), New discrimination techniques for Euler deconvolution, Comput. Geosci. 30, 5, 461-469, DOI: 10.1016/j.cageo.2004.03.006.
Gianelli, G., and M. Taklemariam (1993), Water-rock interaction processes in the Aluto-Langano geothermal field (Ethiopia), J. Volcanol. Geoth. Res. 56, 4, 429-445, DOI: 10.1016/0377-0273(93)90007-E.
Götze, H.-J., and S. Krause (2002), The Central Andean gravity high, a relic of an old subduction complex? J. South American Earth Sci. 14, 8, 799-811, DOI: 10.1016/S0895-9811(01)00077-3.
Grauch, V.J.S., and L. Cordell (1987), Limitations of determining density or magnetic boundaries from the horizontal gradient of gravity or pseudogravity data. Short note, Geophysics 52, 1, 118-121, DOI: 10.1190/1.1442236.
Huang, D., D. Gubbins, R.A. Clark, and K.A. Whaler (1995), Combined study of Euler’s homogeneity equation for gravity and magnetic field, 57th Conf. and Tech. Exhib., Euro. Assoc., Expl. Geophys, Extended abstracts, 144.
Kazmin, V. (1975), Explanation of the geological map of Ethiopia, Bull. Geol. Surv. Ethiopia 1, 14.
Klingele, E.E., I. Marson, and H.-G. Kahle (1991), Automatic interpretation of gravity gradiometric data in two dimensions: Vertical gradient, Geophys. Prospect. 39, 3, 407-434, DOI: 10.1111/j.1365-2478.1991.tb00319.x.
Marson, I., and E.E. Klingele (1993), Advantages of using the vertical gradient of gravity for 3-D interpretation, Geophysics 58, 11, 1588-1595, DOI: 10.1190/1.1443374.
Mohr, P.A. (1967), The Ethiopian rift system, Bull. Geophys. Obs. Addis Ababa 11, 1-65.
Phillips, J.D. (1998), Processing and interpretation of aeromagnetic data for the Santa Cruz Basin-Patahonia Mountains area, South-Central Arizona, U.S. Geological Survey Open-File Report, 02-98.
Reid, A.B., J.M. Allsop, H. Granser, A.J. Millett, and I.W. Somerton (1990), Magnetic interpretation in three dimensions using Euler deconvolution, Geophysics 55, 1, 80-91, DOI: 10.1190/1.1442774.
Spector, A., and B.K. Bhattacharyya (1966), Energy density spectrum and autocorrelation function of anomalies due to simple magnetic models, Geophys. Prospect. 14, 3, 242-272, DOI: 10.1111/j.1365-2478.1966.tb01760.x.
Spector, A., and F.S. Grant (1970), Statistical models for interpreting aeromagnetic data, Geophysics 35, 2, 293-302, DOI: 10.1190/1.1440092.
Teklemariam, M., and K. Beyene (2005), Geothermal exploration and development in Ethiopia. In: Proc. World Geothermal Congress 2005, 24-29 April 2005, Antalya, Turkey, 1-9 (CD).
Teklemariam, M., S. Battaglia, G. Gianelli, and G. Ruggieri (1996), Hydrothermal alteration in the Aluto-Langano geothermal field, Ethiopia, Geothermics 25, 6, 679-702, DOI: 10.1016/S0375-6505(96)00019-3.
Thompson, D.T. (1982), EULDPH: A new technique for making computer-assisted depth estimates from magnetic data, Geophysics 47, 1, 31-37, DOI: 10.1190/1.1441278.
Cytuj : Bogusz, J. ,Saibi, H. , Analysis and interpretation of gravity data from the Aluto-Langano geothermal field of Ethiopia. Acta Geophysica Vol. 60, no. 2/2012