Magnetotelluric Investigation of the Kasane Geothermal Area in Northwest Botswana
Calistus RAMOTOROKO, Andreas JUNGE and Elisha SHEMANG
Kasane is a famous tourist destination in Botswana. Its pleasant climate, especially in spring and summer seasons, is always worthy for most visitors and residents. Kasane hot spring at the meeting point of four countries – Botswana, Zambia, Namibia and Zimbabwe, with a temperature of 43.5 ºC is the only known hot spring which exits in Botswana. It lies at about 145 m south of the Chobe River, northwest Botswana. There are no scientific studies on Kasane hot spring and we do not know of the existence of other hot springs in the area. This research is the first detailed research on hot springs in Botswana and an ongoing effort started early 2018 with the goal of developing a conceptual model for the Kasane geothermal hot spring based on the conductivity distribution at depth. Together with additional geological and geochemical studies, the magnetotelluric results are used to infer a comprehensive understanding of the Kasane geothermal hot spring, particularly about the reservoir and the heat source. The data is acquired by a mixture of Phoenix and Metronix MT systems at various sample rates for approximately 12 hrs. The acquired MT time-series data are processed using industry standard processing software. After data processing, the modelling is performed with a combination of COMSOL Multiphysics and MATLAB. Also, Egbert’s (2012) ModEM code and Mackie’s (2012) magnetotelluric inversion code are used for the 3-D inversion of the MT responses. The 3-D modelling results are compared and we evaluate the differences between the two 3-D resistivity models and discuss the implications any differences and similarities have for the definition of the geothermal reservoir and resource. The results will not only provide geothermal reservoir conditions but also insight into potential efficiency drilling and fracturing in the reservoir.
|        Topic: Geophysics||Paper Number: 13024|