Using Broadband Seismology To Resolve The Structure Of The Crust And Uppermost Mantle Of The Kaapvaal Craton

This paper summaries ongoing research and some preliminary results as part of<br>current seismological studies of the crust and upper mantle at the Bernard Price<br>Institute of Geophysical Research. The research project aims at solving problems in<br>crustal evolution and geodynamics in southern Africa. Anisotropy will be quantified<br>using Moho mode converted phases and shear waves from mining-induced and<br>teleseismic earthquakes. Stacking can be applied at each station to mining tremors<br>with repetitive sources and forms the basis of a pilot study of improvement to the<br>identification of seismic phases at short distances. The events to be stacked are<br>carefully selected depending on epicentral distance, azimuth and data quality. The<br>traces are then aligned by cross correlation, linear shifting and summing. The weak P<br>arrival becomes distinct in the stacked trace. Other phases such as PmP, S, SmS, can<br>then be more easily identified. A One-D ray tracing (assuming a flat earth model)<br>modelling is employed to aid in picking the different phases.