Fracking in South Africa's Karoo Basin could trigger stronger earthquakes, study warns
A new study from the University of Cape Town raises concerns about seismic risks in South Africa’s Karoo Basin. The region, roughly the size of Texas, holds vast hydrocarbon deposits and is under consideration for commercial fracking. Researchers warn that fluid injection from shale gas extraction could trigger earthquakes along existing faults. The study examined 66 earthquakes in the Leeu Gamka cluster between 2007 and 2022. These tremors ranged from magnitude 0.7 to 4.8 and occurred at depths where carbon-rich shale is found. The team identified a critically stressed fault stretching over 30 kilometres, aligned with larger quakes in the area.
Microseismic activity appeared linked to deeper geological structures. Researchers noted that similar regions, like Koffiefontein and Tulbagh, have already experienced significant earthquakes in the past. Geoscientist Raymond Durrheim emphasised that no region is entirely free from seismic risk, especially when fluid injection is involved. Alastair Sloan, a co-author of the study, recommended installing more seismometers to monitor activity. With South Africa planning to lift a 13-year ban on shale gas exploration by late 2025, the findings suggest that fracking could destabilise existing faults. The study highlights the need for careful assessment before industrial operations begin.
The research challenges the assumption that the Karoo Basin is seismically stable. If fracking proceeds, fluid injection may increase earthquake risks along known faults. Authorities will need to weigh these findings against plans for shale gas development in the region.
