Opponents of the oil drilling practice of fracking are unmoved by a report showing the controversial process does not cause earthquakes.
The GNS Science study – commissioned by Taranaki Regional Council – was released yesterday in response to growing public and media scrutiny of fracking.
"There is no evidence that hydraulic fracturing activities in Taranaki between 2000 and mid-2011 have triggered, or have had any observable effect on, natural earthquake activity," the conclusion states.
Neither would there be any earthquake caused by long-term deep injection activities.
The earthquake study follows TRC's report last year stating fracking posed no meaningful risk of contaminating Taranaki fresh water.
However, Gareth Hughes, Green Party spokesman on energy and fracking, said the process should be halted "in the interests of caution", including an investigation by the parliamentary commissioner for the environment.
"Earthquakes are but one of only a number of concerns the public, environmentalists and farmers have – along with concerns around water quality, air pollution.
"In Taranaki for a number of years, fracking was happening under the public and the council's radar to some degree.
"It's good there's a public discussion around it so we welcome GNS doing it, but in the interests of water safety, air safety and potentially earthquake risks – that's why we think there should be a moratorium.
"Many countries and states around the world are banning it or placing moratoriums because they've got enough concerns around this controversial process."
TRC's director of environment quality Gary Bedford said fracking is a slow process and being 4km underground the rock creates a "back pressure".
"You can't get a runaway fracking activity," he said.
Fracking causes a "shift trigger" in the earth of a few millimetres, whereas an earthquake along a fault line would travel hundreds and thousands of miles, Mr Bedford said.
"There's no sensible comparison between the two.
"Where we've had drilling activity in the region, we've had no earthquakes whatsoever," Mr Bedford said.
GNS Science used data from GeoNet seismic monitoring stations around Taranaki.
An email is circulating advising of a public meeting at Stratford Memorial Hall next Wednesday calling for a fracking moratorium and discussing Taranaki council's regulations on the oil and gas industry.
It was passed to Taranaki Daily News by South Taranaki District councillor Michael Self, on behalf of Ngaere resident Sarah Roberts, a fracking critic.
Chief executive Basil Chamberlain said TRC monitored fracking according to risk and despite the report, fracking opponents "will not be satisfied, regardless".
Todd Energy CEO Paul Moore welcomed the findings.
"We are pleased to see the report supports our long-term assertion that hydraulic fracturing does not trigger earthquakes in New Zealand.
"This is further evidence to show that hydraulic fracturing has been conducted in a safe and responsible manner in New Zealand."
GNS studied 3300 earthquakes in Taranaki from 2000-2011, focusing on areas within 10km of any fracking location and occurring within three months of fracking activity. Only one quake – at Kaimiro near Inglewood – happened right on the 10km boundary and it happened three months later.
Mr Bedford said Kaimiro was an active fault line and earthquakes had happened before fracking took place there.
- Taranaki Daily News