The structure of the crust and upper mantle to depths of 320 km beneath the Kaapvaal craton, from P wave arrivals generated by regional earthquakes and mining-induced tremors

✍ Scribed by C. Wright; M.T.O. Kwadiba; E.M. Kgaswane; R.E. Simon

• Publisher: Elsevier Science
• Year: 2002
• Tongue: English
• Weight: 341 KB
• Volume: 35
• Category: Article
• ISSN: 1464-343X
• DOI: 10.1016/s0899-5362(02)00157-4

✦ Synopsis

Travel times from earthquakes recorded at two seismic networks were used to derive an average P wavespeed model for the crust and upper mantle to depths of 320 km below southern Africa. The simplest model (BPI1) has a Moho depth of 34 km, and an uppermost mantle wavespeed of 8.04 km/s, below which the seismic wavespeeds have low positive gradients. Wavespeed gradients decrease slightly around 150 km depth to give a ÔkneeÕ in the wavespeed-depth model, and the wavespeed reaches 8.72 km/s at a depth of 320 km. Between the Moho and depths of 270 km, the seismic wavespeeds lie above those of reference model IASP91 of