A gas flare burns at a fracking site in rural Pennsylvania. Fracking involves the high-pressure injection of sand, water and chemicals into shale to crack it open and allow the flow of gas or oil.

One of the emerging concerns about fracking in several parts of the world was the risk of inducing earthquakes, local scientists warned in a comprehensive technical report yesterday.

Experts appointed by the Academy of Science of South Africa said while the fracking process could activate dormant faults in underground rock, the major earthquake-related risks were caused by pumping large volumes of water underground after the process was completed.

While fracking itself rarely triggered earthquakes large enough to be felt by people, several studies showed that re-injecting wastewater and process water could affect large areas of underground rock and could induce a “significant earthquake”.

A separate report from the Oklahoma Geological Survey last year said the seismicity rate in that state had increased 600 times above historical background rates since oil and gas companies had begun re-injecting process water underground, and that earthquake swarms now affected 15% of the land surface of Oklahoma. Historically, state geologists had measured an average of two earthquakes each year above magnitude 3 on the Richter Scale. By last year, the number of earthquakes of this scale had increased to two each day. It was considered “very likely” that they were caused by the underground injection of water by oil and gas companies and that residents of Oklahoma should now be prepared to deal with a significant earthquake.

The new Academy of Science of SA report recommends that South Africa launch a detailed research project before any fracking starts, to measure the state of natural seismic activity, along with further studies to map ultra-deep geological structures. Most importantly, it was essential to commission a series of independent “baseline studies” to measure and record existing levels of water, air and soil contamination in the Karoo.

These studies should record pre-drilling background levels of nearly 30 types of chemicals, toxic heavy metals and other parameters in order to produce a defensible court record requiring proof beyond a reasonable doubt. Unless this happened, landowners would never be able to sue for compensation if people, land, water or animals were harmed or polluted in future from fracking.

Another concern was that “South Africa has presently neither the monitoring capability nor the regulatory or enforcement capacity to provide any sense of security to citizens that extraction of shale gas would not cause long-term environmental damage.”

The report says the promise of local economic growth in the Karoo from fracking was based largely on experience in the US, but these predictions were “far from conclusive”. Rapid industrialisation of parts of the Karoo “might ironically hold real dangers for rural livelihoods” and potentially lead to “widespread job losses”.

“Any threat to the sustained supply of the available potable water in the region will have a devastating effect on local livelihoods and is particularly relevant to the water-intensive nature of the hydraulic fracturing process. This concern requires serious consideration by policy-makers and regulators, as it lies at the centre of community concerns across all sectors in the Karoo.”