TY - JOUR
T1 - Analysis and interpretation of magnetotelluric data in characterization of geothermal resource in Eburru geothermal field, Kenya
AU - Maithya, Justus
AU - Fujimitsu, Yasuhiro
N1 - Funding Information:
The authors would like to thank the Kenya Electricity and Generating Company (KenGen) for providing MT data for use in this research. We would also like to thank the Japan International Cooperation Agency (JICA) for supporting this research. The authors also thank Gary Egbert and Anna Kelbert for providing the ModEM code for 3-D MT inversion. Finally, we wish to thank the editor and the three anonymous reviewers for the valuable comments and their constructive suggestions to improve the manuscript.
Publisher Copyright:
© 2019 Elsevier Ltd
Copyright:
Copyright 2019 Elsevier B.V., All rights reserved.
PY - 2019/9
Y1 - 2019/9
N2 - The magnetotelluric method (MT) is an essential geophysical method for the exploration of geothermal systems. In this study, the MT method was used to assess the extent of the geothermal resource in Eburru geothermal field, Kenya, with the aim of delineating the electrical conductivity structure of the area. Dimensionality analyses demonstrated that the MT data could be interpreted using two-dimensional approaches, but some localized 3-D effects were detected. A 2-D MT inversion was performed to generate resistivity models of Eburru geothermal field. Given its ability to recover complex resistivity models for the ground, three dimensional (3-D) MT inversion was also carried out, and a joint interpretation made from the 2-D and 3-D models. Both inversion approaches gave similar results and revealed a low resistivity layer (<10 Ωm) interpreted as clay cap, and an intermediate resistivity beneath interpreted as a geothermal reservoir immediately below the low resistivity. The sequence here infers the presence of geological structures controlling the geothermal system. The resistivity profiles analyzed revealed a structure of low resistivity (<10 Ωm) interpreted as the fluid pathway. This structure trend an S-N direction which is consistent with the faults orientation in the field and serves as a conducting channel for transporting heat from the heat source to the shallow region approximately 2 km above sea level.
AB - The magnetotelluric method (MT) is an essential geophysical method for the exploration of geothermal systems. In this study, the MT method was used to assess the extent of the geothermal resource in Eburru geothermal field, Kenya, with the aim of delineating the electrical conductivity structure of the area. Dimensionality analyses demonstrated that the MT data could be interpreted using two-dimensional approaches, but some localized 3-D effects were detected. A 2-D MT inversion was performed to generate resistivity models of Eburru geothermal field. Given its ability to recover complex resistivity models for the ground, three dimensional (3-D) MT inversion was also carried out, and a joint interpretation made from the 2-D and 3-D models. Both inversion approaches gave similar results and revealed a low resistivity layer (<10 Ωm) interpreted as clay cap, and an intermediate resistivity beneath interpreted as a geothermal reservoir immediately below the low resistivity. The sequence here infers the presence of geological structures controlling the geothermal system. The resistivity profiles analyzed revealed a structure of low resistivity (<10 Ωm) interpreted as the fluid pathway. This structure trend an S-N direction which is consistent with the faults orientation in the field and serves as a conducting channel for transporting heat from the heat source to the shallow region approximately 2 km above sea level.
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U2 - 10.1016/j.geothermics.2019.04.003
DO - 10.1016/j.geothermics.2019.04.003
M3 - Article
AN - SCOPUS:85064262363
SN - 0375-6505
VL - 81
SP - 12
EP - 31
JO - Geothermics
JF - Geothermics
ER -
