|
The U.K. regulator based its headline-making conclusions on four separate reports that it requested after just one company, Caudrilla Resources, set off a swarm of earthquakes in 2018 at Preston New Road in the Bowland Shale in northern England.
Over a two-month period, the fracking operation authored a total of 57 seismic events.
Six tremors exceeded the maximum “red light” threshold of magnitude 0.5 in the U.K., a system that suspends activity in an effort to prevent larger quakes. (The thresholds in Canada are a much more liberal magnitude three or four.)
As a result of the earthquake swarm, the regulator ordered an investigation in February.
Since then, Caudrilla submitted another fracking plan to authorities, and this time it generated a magnitude 2.9 quake that was widely felt by rural homeowners last August.
That tremor forced the suspension of activity at the well site, and Caudrilla has now abandoned the operation.
In any case the U.K. authority tabled the results of its investigation nine months later.
(In contrast, neither B.C. nor Alberta regulators have tabled reports on two respective magnitude 4.5 and 4.2 tremors that shook hundreds of residents last November and March near Fort St. John, B.C. and Red Deer, Alta.)
The four critical U.K. studies offer a number of conclusions and observations that Canadian politicians, regulators, researchers and landowners need to seriously ponder.
One of the more salient findings is this: “It is thus clear that induced seismicity can give rise to significant events in the range of [magnitude 4.0 to 6.0], indicating that, at least in the case of shale gas and Enhanced Geothermal System activities, more energy can be released than has been introduced by the injected fluids.”
A technical study examining the cause of the quakes at Preston New Road highlighted that fracking provoked chaotic and unpredictable seismic responses in the ground just as The Tyee has consistently reported for years.
“For starters many events occur at large distances from the well for stages with only small injection volumes and that events occur near-instantaneously across a range of distances,” said the report.
Another study that looked at the impact of industry-triggered seismicity on people and buildings, something neither B.C. nor Alberta regulators have publicly done.
It confirmed that the hazards were daunting.
A magnitude 3.5 earthquake would mean “perhaps one per cent of all buildings in the study area would sustain cracked plasterwork, and 0.2 per cent would sustain slight structural damage or moderate non-structural damage, with 0.1 per cent of buildings possibly sustaining chimney failure.”
A magnitude 4.5, which both B.C. and Alberta have experienced in rural areas, would result in “widespread building damage in the study area, with cracked plasterwork affecting approximately 10 per cent of buildings, more serious structural damage (of varying degrees) affecting 5.4 per cent of buildings, and 5.4 per cent also likely to suffer chimney failure. Some damage would be caused to buildings outside of the study area.”
The hazard risk report added that “Experience from Preston New Road shows that there is very limited tolerance to seismic events that are felt, and that even very few events are likely to be considered a public nuisance.”
A third study found that industry forecasting abilities were largely deficient.
It reported that four models were tested “against the observed seismicity using the injection volume and seismicity for each fracturing stage separately, [but] they were not very successful in forecasting maximum magnitude.”
In addition, “the forecasts lose their sensitivity to the cumulative injection volume.”
A fourth report looked at the situation in Canada and other jurisdictions and once again pointed out the failings of “traffic light systems,” or the idea that industry can prevent big quakes by shutting down operations when they make smaller quakes.
However, the U.K. regulator noted Canada’s traffic light systems weren’t very restrictive. The traffic light thresholds in Canada “have typically been set quite high even at the ‘amber’ level with ‘red’ thresholds close to the maximum size of event subsequently observed.”
In B.C. for example, the oil and gas industry has to report magnitude 1.5 quakes around Fort St. John and the Site C dam, but doesn’t have to shut down operations until it has triggered a magnitude 3.0 tremor.
In addition, “mitigation protocols do not appear to take into account the real-time development of the frequency or location of potential precursors to larger events.”
In jurisdictions where industry has set off magnitude 4.0 quakes such as China and Canada, “either no [traffic light system] was in place, the system was not followed or the thresholds were so large as to be ineffective.”
Last but not least, it was noted that the U.K. had the most restrictive traffic light system in the world. Operators must shut down once they have caused a magnitude 0.5 quake to minimize the probability of greater quakes.
Unlike other jurisdictions, U.K. authorities have collected more scientific information on industry quakes, including event data, pumping data, a summary of produced water, screen shots of the hydraulic fracturing operations, and a seismic event video. (Corporate confidentiality has prevented such data sharing in Canada.)
Yet even with more scientific data and tighter rules, U.K. authorities admit they have not been able to prevent tremors that posed a hazard to the public.
Both the seismic science and shaky economics probably helped to convince the Conservative government to temporarily ban fracking. (If the science changes, Tory ministers have said they might change their minds.)
But politics and an upcoming election played a major role too. Rural Conservative MPs, many who openly characterize fracking as “downright bonkers,” have warned about its political liabilities for years.
These liabilities include the industrialization of farmlands, damaged roads, depleted aquifers, methane leaks, eroded house prices, a wounded tourism industry and alienated voters.
| 
