Fracking and earthquakes
The South African government is looking into fracking to reduce the country’s huge reliance on coal for energy. Fracking involves pumping high pressured fluids into rock formations to release reserves of oil and gas.
Estimates for gas deposits in the main Karoo region of South Africa range widely. A few studies have been done for government on the potential for shale gas in the country. These include a report on the technical readiness for a shale gas industry, a strategic environmental assessment on shale gas and a multi-authored academic book on hydraulic fracturing in the Karoo. Government must now integrate this information into policy and develop regulations for the fracking industry.
Environmental groups and landowners are concerned about the negative environmental and the social impact of fracking. They say that it could have an impact on water quality and quantity, and could also cause habitat fragmentation and loss. They are also worried about possible increased seismicity associated with deep well waste water injection and fracking operations.
Our research set out to look at the link between earthquakes and fracking. It formed part of the vulnerability mapping for fracking in South Africa. We found that the areas with the highest vulnerability for seismicity linked to fracking were in the parts of Western Cape, Gauteng, North West Province, Mpumalanga, KwaZulu-Natal and one of South Africa’s neighbours, Swaziland. Even though no gas is expected to be found in many of these areas, they would still be prone to the seismic effects of fracking in the Karoo basin, the site of what is assumed to bethe country’s biggest gas deposits.
Seismic hazards in South Africa are not high by international norms. But there could be significant damage to infrastructure if seismicity increases.