Presenter: Prof Hiroshi Ogasawara, Ritsumeikan University
Presenter: Dr Eldridge Kgaswane, Council for Geoscience
Presenter: Prof Raymond (Ray) Durrheim, University of the Witwatersrand
Earthquakes have caused some of the deadliest and costliest disasters of the 21st century. Natural earthquakes and associated tsunamis pose a significant risk to inhabitants of regions close to the boundaries of tectonic plates, such as Japan; while mining-induced earthquakes are a major risk in deep mines, such as South African gold and platinum mines. However, deep mines also provide a unique laboratory to study the build-up of stress in the rock and the sudden and sometimes catastrophic release of energy when the rock fails. Since 1994, Japanese and South African scientists and engineers have collaborated in research aimed at reducing the risk posed by earthquakes. Two main strategies have emerged. Firstly: to manage the build-up of stress in the rock. This is possible for mining-induced earthquakes, but not for natural earthquakes. Secondly: to reinforce mining excavations and buildings so that they do not collapse when subjected to strong shaking. Efforts have also been made to predict when and where a damaging earthquake will occur, but reliable prediction remains a distant and perhaps impossible goal. The talks will present the achievements of completed collaborative projects and the goals and challenges of current research.
Professor Hiroshi Ogasawara (PhD, Kyoto University, Japan, 1989) is Vice Dean (FY2016-7) of the College of Science and Engineering, Ritsumeikan University. He has carried out seismological research in South African gold mines since 1992, and is now principal investigator of the ICDP project “Drilling into seismogenic zones of M2.0 – M5.5 earthquakes from deep South African gold mines” (DSeis, 2016-present). He was co-leader of the Japanese-South African collaborative project “Observational studies in South African mines to mitigate seismic risks” (JST-JICA SATREPS; 2010-2015).
Dr Eldridge Kgaswane (PhD, University of the Witwatersrand, 2013) has been in the employ of the Council for Geoscience (as a seismologist) since 2001. He is primarily involved in structural seismology, seismic monitoring and instrumental seismology. He provides technical assistance to the electronic lab for the siting of new seismic stations and the analysis of calibration and instrumentation (state-of-health) test results. He also carries out research into new analytical methodologies in structural seismology and seismic monitoring. He has been involved in a number of internal and collaborative projects e.g. Kaapvaal project (SASE), AfricaArray, SIMRAC, MHSC, and Disaster Management (part of Microzonation project).
Prof Raymond (Ray) Durrheim, University of the Witwatersrand
Prof Ray Durrheim was born in Bloemfontein in 1956. He is a graduate of Stellenbosch (BSc, 1977), Wits (BSc Hons, 1978 and PhD, 1990), Pretoria (MSc, 1984), and UNISA (BA, 1984). He started his career in 1979 as an exploration geophysicist with Gencor. He was involved in gold, coal and base metal projects, gaining field and interpretation experience in ground and airborne magnetics, gravity, resistivity, CSAMT, IP, ground and airborne EM. During his National Service (1979-81) he was seconded to the Geological Survey, where he conducted geotechnical investigations.
Ray was appointed a lecturer in the Geophysics Department, Witwatersrand University in 1983, where his research activities included investigations of the crust and upper mantle using both explosive and mine tremor energy sources, and the application of the reflection seismic method to gold and platinum exploration. He was appointed to the Wits/CSIR South African Research Chair in Exploration, Earthquake and Mining Seismology in April 2007.
Durrheim is co-director of the AfricaArray collaborative programme and Principal Investigator of the Japan-SA collaborative project Observational studies in South African mine to mitigate seismic risks. Data for many of his projects are supplied by the AfricaArray permanent network of 49 broadband stations in sub-Saharan Africa, and various temporary project specific deployments (e.g. East African Rift, Congo Craton, Far West Rand gold fields) and various networks in gold and platinum mines.