Recent studies reveal that the practice of hydraulic fracturing, commonly known as fracking, even when conducted with liquid carbon dioxide, is responsible for minor seismic activities that were earlier not definitively linked to the activity. Fracking with CO2 has environmental benefits, including carbon sequestration, but both CO2-based and water-based fracking can trigger these seismic events, with the risk of escalating into more significant, destructive earthquakes.
The latest research has established that hydraulic fracturing is the causative agent behind previously inexplicable, minor, slow-paced seismic events. The seismic activities emanate from processes capable of inducing larger, detrimental earthquakes.
Hydraulic fracturing is a procedure in which fluids are injected forcibly beneath the Earth’s crust to extract oil and natural gas. Although wastewater is the conventional medium used, this particular study focused on the effects when liquid carbon dioxide is utilized. This technique sequesters carbon below ground, thereby mitigating its role in atmospheric warming.
By certain calculations, the annual carbon-saving potential of fracking with liquid carbon dioxide could equate to that of one billion solar panels. Using liquid CO2 for hydraulic fracturing is environmentally more favorable than employing wastewater, which does not sequester carbon.
“Given that this research focuses on a method that effectively stores carbon underground, it might carry positive ramifications for sustainability and climate science,” stated Abhijit Ghosh, an associate professor of geophysics at UC Riverside and co-author of the study published in the journal Science.
Owing to the liquid state of carbon dioxide, Ghosh affirmed that the study’s findings are likely applicable to water-based fracking as well, both types being probable culprits for causing tremors.
Seismographically, regular earthquakes and tremors exhibit distinct characteristics. While larger earthquakes result in sudden, high-amplitude jolts, tremors manifest as gradual, low-amplitude oscillations above the baseline noise, which then slowly dissipate.
“We find it encouraging that these tremors can now be employed to trace fluid migration from hydraulic fracturing and monitor fault movements resulting from the injections,” Ghosh added.
Earlier, the origins of these tremors were a subject of contention among seismologists. Some theories posited that the seismic activities might be reverberations from large-scale earthquakes occurring thousands of miles away, whereas others suspected they could be anthropogenic noise, such as from transportation or industrial operations.
“Seismometers are not discerning instruments. Any local vibration, whether it’s a nearby vehicle or even a kick, gets recorded,” Ghosh noted. “This ambiguity is why it took us a while to conclusively determine that the seismic activities were indeed related to fluid injections.”
For this research, seismometers were strategically positioned around a hydraulic fracturing site in Wellington, Kansas. The data encompassed a six-month period during fluid injections, as well as a month before and after the injections. After filtering out the background noise, it was evident that the remaining seismic signals originated below ground and coincided with the time frame of fluid injections. “The absence of tremors before and after the injection phase suggests a causal link,” said Ghosh.
It has long been recognized that hydraulic fracturing could catalyze larger earthquakes. One preventative measure could be the cessation of fracking activities. Since this seems improbable, Ghosh emphasizes the importance of ongoing surveillance to understand how subsurface geological structures are affected and to track fluid migration post-injection.
Computational experiments are frequently carried out to guide companies in determining safe fluid injection pressures. Adhering to these established parameters minimizes the risk of fluids migrating towards unidentified, large faults, thereby avoiding catastrophic seismic events. However, it must be noted that not all underground faults are known or mapped.
“Our modeling capabilities are restricted to known faults. The existence of unmapped faults implies that our predictions may not always be accurate,” concluded Ghosh.
Reference: “Tremor signals during fluid injection are generated by fault slip” by Shankho Niyogi, Abhijit Ghosh, Abhash Kumar, and Richard W. Hammack, published on August 3, 2023, in the journal Science.
DOI: 10.1126/science.adh1331
Table of Contents
Frequently Asked Questions (FAQs) about Hydraulic Fracturing and Seismic Activities
What is the primary focus of the recent research on hydraulic fracturing?
The research primarily focuses on establishing a link between hydraulic fracturing (fracking) and previously unexplained minor seismic activities. It also examines the environmental implications of using liquid carbon dioxide in fracking as opposed to conventional wastewater.
Is hydraulic fracturing responsible for minor seismic activities?
Yes, the study confirms that hydraulic fracturing is responsible for previously unexplained, slow-paced, minor seismic events, which could potentially escalate into larger, more damaging earthquakes.
What is the significance of using liquid carbon dioxide in fracking?
Using liquid carbon dioxide in fracking has the advantage of sequestering carbon deep into the Earth, thereby reducing its contribution to atmospheric warming. It is considered more environmentally friendly compared to using wastewater.
Who led the study and where was it published?
The study was co-authored by Abhijit Ghosh, an associate professor of geophysics at UC Riverside, and it was published in the journal Science.
How do regular earthquakes differ from the tremors caused by fracking on a seismograph?
On a seismograph, regular earthquakes manifest as sudden, high-amplitude jolts, whereas tremors appear as gradual, low-amplitude oscillations above the baseline noise, which then slowly dissipate.
What was the earlier debate among seismologists regarding these tremors?
Previously, there was uncertainty among seismologists about the origins of these tremors. Some theories posited that the tremors could be aftershocks from large-scale earthquakes occurring thousands of miles away, while others suspected they could be anthropogenic noise, such as from transportation or industrial operations.
How did researchers conclude that the tremors were related to fracking?
Researchers used strategically positioned seismometers around a fracking site in Wellington, Kansas, and analyzed data from a six-month period during fluid injections. After filtering out background noise, the remaining seismic signals were found to originate below ground and coincided with the time frame of fluid injections.
Are there ways to minimize the risks associated with hydraulic fracturing?
While completely stopping hydraulic fracturing could eliminate the risks, such a step is considered unlikely. Researchers emphasize the importance of monitoring to understand subsurface geological changes and to track fluid migration after injection. Computational models are also used to determine safe fluid injection pressures.
Are all faults underground known and mapped?
No, not all faults are known or mapped. This limitation means that predictive modeling is restricted and may not always be accurate in forecasting seismic activities triggered by fracking.
What are the potential environmental benefits of using liquid CO2 in fracking?
By some estimates, using liquid CO2 for hydraulic fracturing could sequester as much carbon annually as one billion solar panels, thereby contributing to sustainability and climate science objectives.
More about Hydraulic Fracturing and Seismic Activities
- Study on Hydraulic Fracturing and Seismic Activities
- Abhijit Ghosh’s Research Profile at UC Riverside
- Journal Science Publication
- Environmental Impacts of Fracking
- Seismological Society of America
- Carbon Sequestration Methods
- Hydraulic Fracturing Overview
- Wellington, Kansas Fracking Site
- Computational Models in Fracking
- Climate Science and Carbon Sequestration
8 comments
Wow, never knew fracking could cause those tremors. Always thought it was just big quakes that we had to worry about.
So we’re basically trading one environmental problem for another? Sequestering carbon is great but triggering earthquakes? Not cool.
A billion solar panels worth of carbon saved? Thats huge but still, earthquakes? need to weigh the pros and cons here.
Risky business this fracking, even with all the computational models. What if there’s a fault we don’t know about?
Interesting stuff. But why cant we just stop fracking altogether? Seems like a no-brainer to me!
abhijit Ghosh huh. gonna look up more of his work, seems legit.
Seismometers aren’t smart lol. Good to know they figured out the source of those tremors.
Carbon dioxide in fracking, that’s a new one for me. Curious how much carbon it actually saves tho.