Journal : Acta Geophysica
Article : DC resistivity and seismic refraction survey across the SE margin of Lake Ngami, NW Botswana

Authors :
Yamasaki, K.
Department of Earth and Planetary Sciences, Faculty of Science, Kobe University, Nada, Kobe, Japan,,
Teisseyre, R.
Institute of Geophysics, Polish Academy of Sciences, Warszawa, Poland,,
Herak, M.
University of Zagreb, Faculty of Science and Mathematics, Department of Geophysics, Zagreb, Croatia,,
Rosyidi, S. A. P.
Department of Civil Engineering, Muhammadiyah University of Yogyakarta, Yogyakarta, Indonesia,,
Moustafa, S. S. R.
Department of Seismology, National Research Institute of Astronomy and Geophysics, Helwan, Cairo, Egypt,,
Tenzer, R.
School of Surveying, Faculty of Sciences, University of Otago, Dunedin, New Zealand,,
Rabeh, T.
National Research Institute of Astronomy and Geophysics, Cairo, Egypt; Center of Geophysics, Faculty of Science IGIDL, Lisbon University, Lisbon, Portugal,,
Węglarczyk, S.
Cracow University of Technology, Faculty of Environmental Engineering, Kraków, Poland,,
Huo, Y.
China University of Geosciences, Beijing, China,,
Shemang, E. M.
Department of Geology, University of Botswana, Gaborone, Botswana,,
Abstract : Seismic refraction survey and DC resistivity measurements were made across the margin of the Lake Ngami. The structure and stratigraphy at the lake were determined. High resolution aeromagnetic data showed a prominent anomaly coinciding with the Kunyere Fault. Estimated depths to magnetic sources are increasing towards the lake. Two velocity layers were mapped. The top layer (500 m/s) is thin outside the lake and thicker inside the lake. The underlying layer (3125 m/s) has undeterminable thickness. Resistivity sounding results inside the lake showed that the low velocity layer has four sub-units: dry hard clays; diatomaceous earth; soft clays interlayered with silts; and wet whitish clays interlayered with silts. Normal faults were mapped along the profile with a total displacement up to 50 m. The results of the study indicate that the formation of the Lake Ngami basin was structurally controlled and probably initiated by the tectonics of the Okavango Rift Zone.

Keywords : seismic refraction, resistivity, Lake Ngami, Okavango Rift Zone, Botswana,
Publishing house : Instytut Geofizyki PAN
Publication date : 2009
Number : Vol. 57, no. 3
Page : 728 – 742

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Qute : Yamasaki, K. ,Teisseyre, R. ,Herak, M. ,Rosyidi, S. A. P. ,Moustafa, S. S. R. ,Tenzer, R. ,Rabeh, T. ,Węglarczyk, S. ,Huo, Y. ,Shemang, E. M. ,Shemang, E. M. , DC resistivity and seismic refraction survey across the SE margin of Lake Ngami, NW Botswana. Acta Geophysica Vol. 57, no. 3/2009