/\ dissertation submitted to the Faculty of Science,
University of the Witwatersrand, Johannesburg
for the Degree of Master of Science. Johannesburg 1994. / This dissertation investigates the upper mantle discontinuities beneath South Africa
by analysing seismic waves converted from p to Sv recorded at an array of broad
band seismometers. Events, with desirable characteristics recorded at each station
are transformed to a suitable coordinate system, normalised, and stacked to enhance
the weak converted phases. Additional low pass filters are also applied to improve
the signal to noise characteristics of the data.
No data suitable to processing were found for stations outside the Kaapvaal craton
Despite additional problems related to the application of sub-optimum numerical
routines to a limited data base, by combining results with those from an independent
study two models were derived for the '400 km' and '670 km' discontinuities beneath
the Craton. Models for the '670 km' discontinuity accord with a simplified global
earth model while models for the '400 km' discontinuity indicate the presence of a low
shear velocity layer not supported in a global earth model. Addltlonal broad band
seismic data must be acquired to investigate this phenomenon further. / AC2017
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:wits/oai:wiredspace.wits.ac.za:10539/22107 |
| Date | January 1994 |
| Creators | Cattermole, Paul Andrew |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | Online resource (97 leaves), application/pdf |
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