Researchers at the University of Colorado-Boulder released a study this week that claims to “for the first time” definitively link several earthquakes that occurred between 2008 and 2010 in the Raton Basin, which spans central Colorado to northern New Mexico, to wastewater disposal from oil and gas activity.
From the study’s abstract:
“We find that modeled pore pressures in the New Mexico portion of the basin (above 0.08 MPa) reached that necessary to induce seismicity (0.01–0.1 MPa). We simulate a fault plane, 20 km long, inferred from seismicity in Vermejo Park (1355 of 1881 total earthquakes), in our model. We find that the relatively permeable fault allows pressures to migrate deeper into the basin at the onset of our study in 2008, providing an explanation for the observed seismicity in the basement.
“The modeled pore pressures, earthquake locations, and relationship between cumulative volume and number of earthquakes indicate that seismicity in the Raton Basin is likely induced.”
Fact #1: This is old news
The study’s lead researcher and CU doctoral student, Jenny Nakai, characterized the study as some sort of breakthrough in an interview with 9News-Denver on Tuesday,
“We have shown for the first time a plausible causative mechanism for these earthquakes. The spatial patterns of seismicity we observed are reflected in the distribution of wastewater injection and our modeled pore pressure change.”
But scientists have actually linked earthquakes in the Raton Basin to wastewater injection for years. In fact, the United States Geological Survey (USGS) linked earthquakes to wastewater injection in a 2014 study. As the Summit County Voice reported in 2014,
“[T]he study details several lines of evidence directly linking the injection wells to the seismicity. The timing and location of the quakes is clearly linked with the documented pattern of injected wastewater.”
Of note, though wastewater injection can trigger induced earthquakes, it is essential to understand that such seismic events are rare. Recently, earthquake activity has subsided in the Raton Basin making this study that looks at earthquakes between 2008 and 2010 nearly 7 years outdated. In fact, a 2017 USGS report forecasting both natural and induced seismicity potential throughout the United States decreased the region’s hazard level from the previous year’s report:
“In March 2016, the USGS released its first induced earthquake hazard model, the 2016 One-Year Seismic Hazard Forecast for the CEUS from Induced and Natural Earthquakes. … Areas of high induced earthquake hazard were identified in Oklahoma-southern Kansas, the Raton Basin (CO/NM border), north-central Texas, and north-central Arkansas.
“In March 2017, the USGS released an updated induced earthquake forecast for the CEUS for 2017. The 2017 one-year forecast uses the same earthquake hazard model and methodology as the 2016 one-year forecast, but incorporates an updated earthquake catalog that includes earthquakes from 2016 (Figure 3). The 2017 forecasted earthquake rates are lower in regions of induced earthquakes due to lower rates of earthquakes in 2016 compared to 2015, which may be related to decreased wastewater injection, caused by regulatory actions or by a decrease in unconventional oil and gas production.”
USGS made sure to flag the following:
“Important Note: In the west, USGS scientists have focused on the hazard from natural earthquakes. Induced earthquakes have been observed in California as well, but they don’t significantly change the regional hazard level, which is already high due to frequent natural earthquakes.”
USGS findings from March 2017 didn’t make news like the new report catching headlines this week, but it has some important information that should be shared:
“‘The good news is that the overall seismic hazard for this year is lower than in the 2016 forecast, but despite this decrease, there is still a significant likelihood for damaging ground shaking in the CEUS in the year ahead,’ said Mark Petersen, chief of the USGS National Seismic Hazard Mapping Project.”
Bottom line: the basic premise of a link between injection wells and induced seismicity in the Raton Basin isn’t news at all, but decreased seismicity is worth at least a headline or two.
Fact #2: No link between earthquakes and fracking
Not only does the study not link the earthquakes to hydraulic fracturing — a completely separate process from wastewater disposal that the press has previously failed to recognize — the researchers are crystal clear that they didn’t study a potential link to fracking.
As Denverite reported:
“In this study, researchers did not look at the relationship between earthquakes and hydraulic fracturing, better known as fracking.”
As 9News-Denver reported:
“The study linked most of the 1,800 earthquakes to wastewater injection well activity, an industry practice that pumps extracted water back into the ground while methane gas is collected from subterranean coal beds. At least 200 million barrels of wastewater has been sent underground in the Raton Basin since 1994, according to the research.”
Bottom line: There is no link between fracking and induced seismicity in the Raton Basin.
Fact #3: Colorado Has Taken Proactive Measures to Address Small Risk of Induced Seismicity
The only relatively recent instance of induced seismicity in Colorado occurred in Greeley — far from the Raton Basin — in June 2014, when the Colorado Oil and Gas Conservation Commission (COGCC) determined that two seismic events could be linked to an injection well.
In response, regulators asked the well’s operating company to lower the pressure and plug the bottom of the well. As Stuart Ellsworth, engineering manager for COGCC, noted,
“I think it’s the answer. It was a remediation effort that reduced the risk of future events.”
The action proved effective, as there have been no further issues in the Greeley — or Colorado as a whole since then. This demonstrates that common sense measures are preferable to some of the extreme legislation that has been proposed by oil and gas opponents in the past.
This new study comes to the conclusion of what other scientists have already found, but takes a view through a different lens by using a different approach to get to the same conclusion. With that said, is this a groundbreaking study? No, not really.