4 November 2011
Media release for immediate use
Call for calm on fracking - Straterra
New Zealanders concerned about hydraulic fracturing (fracking) in oil and gas development are urged to consider the
issues carefully before leaping to conclusions, Straterra says.
Yesterday TV3 covered a report produced in the UK on ground vibrations of 1.4 and 2.3 magnitude on the Richter Scale,
linking these events to fracking near Blackpool. The report and associated news coverage have raised further concerns
over fracking.
Straterra CEO Chris Baker said today there are legitimate concerns about fracking, but it is important to have good
information on the issues, and to interpret this information sensibly.
“Let us consider the earthquake findings. Ground vibrations of 2.3 are comparable to that produced by a bus driving
past. These events have nothing to do with the gigantic forces of nature normally associated with earthquakes.”
“This is not just my opinion. GNS Science has done the research, and our view is based on their science – and, indeed,
on common sense.” (An opinion by Dr Rosemary Quinn is appended to this media release.)
“The resource sector is dismayed at the constant outpouring of ill-informed and misleading comment on fracking. This is
a proven engineering technology that can deliver significant economic benefits in ways that are environmentally
responsible,” Mr Baker said.
“We have the legislation to manage the risks to do with fracking, as is the case with any consented engineering activity
in New Zealand. Certainly, we should ensure the appropriate monitoring is in place, and we would do that anyway as part
of working with the local council under our consents.”
Opinion by Dr Rosemary Quinn, Head of Petroleum Geosciences, GNS Science
There are many examples of activities that cause human-induced seismicity, of which hydraulic fracturing (or ‘fracking’)
is just one. There is a large body of published data that indicates that seismic activity caused by fluid injection (for
solution mining, hydrocarbon production, geothermal energy generation, hazardous and non-hazardous waste disposal
purposes for example) cause small seismic events i.e. magnitude (ML) 3.9. The seismic activity associated with hydraulic
fracturing is generally less than magnitude 2.0, with the magnitude and number of events depending on local geology, the
pressure and duration of the fluid injection, and the injection-rate. The small-size of
earthquakes induced by hydraulic fracturing (compared to those generated by other activities) is partly due to the fact
that fluid injection is for shorter duration (days as opposed to weeks or years) than for other activities.
This induced seismic activity will probably be minor compared to natural background seismicity. In New Zealand, for
example, GeoNet records about 15,000 magnitude 2.5 and larger events in an average year. At the lower end of this scale,
most people are unaware that anything is happening – a passing truck generates as much if not more vibration – so the
effects of seismic activity that are typically induced by hydraulic fracturing would be hard to separate from the
background level of seismicity. The fact that we experience natural earthquakes does not mean that we should be
complacent: hydraulic fracturing operations need to be designed and monitored to ensure that they do not present undue
risk to people and resources. The minimum pressures and flow-rates required to achieve the desired outcome should be
used. If that is done, it is very unlikely that hydraulic fracturing operations will result in any noticeable seismic
impact.