Academic Programmes - Student Biographies
Ph.D. Degree Candidate
University of the Witwatersrand and University of Texas-Austin
I am from Pretoria, South Africa and started in 2006 with a part time PhD in Seismology at the University of the Witwatersrand, Johannesburg, and the University of Texas at Austin. I finished a BSc (Hons) in Geophysics in 1992 at the University of Pretoria. I started working in the Seismology Unit of the Council for Geoscience (one of the founding members of Africa Array) in 1993 in seismic monitoring and hazard assessment at advanced infrastructure such as large dams and nuclear power plants. I spent the winter of 1996 at the University of Munch with Prof. Frank Scherbaum's group and also attended courses at the International Institute of Seismology and Earthquake Engineering in Tsukuba, Japan. I completed an MSc at the University of Bergen, Norway, with Prof. Jens Havskov in 2000. I obtained a certificate in ISO9001:2000 - Quality Management Systems, with the South African Bureau of Standards in 2004 and spent time with Dr. Petre Firbas' group in Vienna in the summer of 2005 as part of the Comprehensive Nuclear Test Ban Treaty Organization's research.
My part time PhD consists of a sandwich programme, I will continue working at the Council for Geoscience with visits to Prof. Steve Grand's group at the University of Texas at Austin while receiving scientific and administrative support from Prof. Gorden Cooper from the University of the Witwatersrand. My primary focus is on the crust, upper and lower mantle of southern Africa to better understand the recent tectonic behavior as well as the forces driving this activity. The tectonic behavior of southern Africa is hypothesized to be related to the “African Superswell” and/or “African Superplume”. The “African Superswell” is one of the largest areally topographic anomalies on Earth by about 500 m of positive residual elevation in eastern African, southern African and the southeastern Atlantic Ocean. The “African Superplume” is a large-scale ridge-like shear wave velocity anomaly inside 3 percent lower than the ambient mantle with its center at the core-mantle boundary underneath Africa.
I will use an inversion technique to invert seismic waveforms for an “optimum fit” to synthetic seismograms calculated with a reflectivity method. This will result in a multiple layer velocity structure of the Earth's crust and upper mantle in southern Africa using earthquakes located in the East African Rift. These one dimensional models for the upper mantle and crust will be improved with seismic tomography. Tomographic images of the lower mantle, the “African Superplume” that may be the ultimate cause of the “Superswell”, will also be inverted. The whole inversion will be performed for a three-dimensional mantle model of S-velocity travel-time residuals for upper mantle ray paths as well as paths through the lower mantle and core. Data will come from the IRIS Kaapvaal broadband craton experiment, the Geofon Namibia broadband experiment, and Africa Array stations. For the tomography an existing data base will be supplemented with new data from Africa Array stations.