Recent research in seismology in South Africa

Abstract

This paper summarizes the most important developments in South African research in earthquake, exploration and mine seismology for the period January 2003 to December 2006. The South African National Seismograph Network (SANSN) has been considerably improved in this time, and the upgraded seismological stations now use the SeisComp recording system and GPRS cellular communications for retrieving data in quasi-real time. The largest mining-related ever to occur in South Africa registered 5.3 on the local Richter magnitude scale (M L) on 9 March 2005. An unusually large earthquake of ML = 7.3 occurred in Mozambique on 23 February 2006, at the southernmost end of the East African Rift System. Improved seismic location and source parameter calculation methods have been developed for the data recorded by the SANSN, and significant research has been completed on seismic hazard and risk methods. The work in mining seismology has been wide-ranging in pursuit of improved understanding of the complex rock mass response to underground mining. Novel underground instrumentation has been developed. A new model of the Bushveld Complex uses seismically determined crustal thickness values to assess its isostatic responses and has important economic implications.