The Geological Society of London* organizes monthly geoscience lectures with invited experts as speakers. In April 2014, Professor Richard Davies from the University of Durham gave a talk titled “Fracked or fiction: so what are the risks associated with shale gas exploitation?” and explained how shale gas and oil extraction is carried out using the fracking process.

The key messages are:

• that fracking has caused earthquakes in the past, but very few have been of sufficient magnitude to be felt, and there are several more familiar industrial processes which generate bigger quakes;
• hydraulic fracturing itself is very unlikely to cause water contamination because fractures are not tall enough to go from the shale layer at 2-3 km depth to the aquifer just below the surface;
• that poor sealing of wells is a mechanism for contamination of the environment, as has been documented in a small number of cases in the USA.

You can watch the lecture online here (available in English).

*The Geological Society of London is the UK national society for geoscience, and the oldest geological society in the world.