@inproceedings{1952_28_Ogasawara, author={Ogasawara, H and Liebenberg, B and Rickenbacher, M and Ziegler, M and van Esterhuizen, H and Onstott, TC and Durrheim, RJ, Manzi, MSD and Mngadi, S and Yabe, Y and Ogasawara, H and Kaneki, S and Cason, E and Vermeuren, J-G and van Heerden, E and Wiersberg, T and Zimmer, M and Kujawa, C and Conze, R and van Aswegen, G and Wechsler, N and Ward, AK and Enslin, S and Tau, S and Bucibo, MS}, editor={Joughin W}, title={2019 status report: Drilling into seismogenic zones of M2.0–M5.5 earthquakes in South African gold mines (DSeis project)}, booktitle={Deep Mining 2019: Proceedings of the Ninth International Conference on Deep and High Stress Mining}, date={2019}, publisher={The Southern African Institute of Mining and Metallurgy}, location={Johannesburg}, pages={375-384}, abstract={In 2014, a M5.5 earthquake ruptured the range of depths between 3.5 km and 7 km near Orkney, South Africa. The main and aftershocks were very well monitored in the nearfield by dense, surface, strong motion meters and a dense underground seismic network in the deep gold mines. The mechanism of this M5.5 earthquake was left-lateral strike-slip faulting, differing from typical mining-induced earthquakes with normal-faulting mechanisms on the mining horizons shallower than 3.5 km depth. To understand why such an unusual event took place, the aftershock zone was probed by full-core NQ drilling during 2017-2018, with a total length of about 1.6 km, followed by in-hole geophysical logging, core logging, core testing, and monitoring in the drilled holes. These holes also presented a rare opportunity to investigate deep life. In addition, seismogenic zones of M2–M3 earthquakes were probed on mine horizons that were also very well monitored by acoustic emission networks. This paper reviews the early results of the project.}, doi={10.36487/ACG_rep/1952_28_Ogasawara}, url={https://papers.acg.uwa.edu.au/p/1952_28_Ogasawara/} }