Fracking has been a contentious subject since the 1980s, though the process has been going on since 1949 in the United States. While environmental safety and health concerns are normally discussed, a new study has suggested that the process also leads to more earthquakes.
The new study was published on Thursday in the journal Science and suggests that fracking, along with the underground disposal of wastewater during the process, leads to more earthquakes.
The process of hydraulic fracturing, or fracking, as it is normally called, involves pushing large amounts of water through rocks to coax out oil and natural gas from underground wells.
Industrial wastewater disposal can make an area more prone to seismic activity preceding a larger event. Along with linking earthquakes near wastewater injection sites in the US, the scientists also linked them to quakes as far away as Japan and Chile.
Lead author Nicholas van der Elst, a seismologist with Columbia University's Lamont-Doherty Earth Observatory, explained, "The fluids are driving the faults to their tipping point."
"Dynamically triggered" earthquakes have been on scientists' radar for more than 20 years. Certain regions are also known to be more vulnerable to this kind of earthquake than others, especially when underground water is superheated by magma. This water can weaken faults and make them more vulnerable to seismic waves from a distant tremor.
Knowing about these quakes made van der Elst and his team wonder if fracking could cause earthquakes like this. Researchers analyzed past earthquakes in the united States, focusing on those that happened after three major world quakes. Study co-author Heather Savage explained:
"We saw that three areas in particular have an increase in seismicity in the days following these big events. These were in Texas, Colorado, and Oklahoma."
The main thing that set these areas apart from the rest of the United States is that fracking has been going on there for decades. This suggests that the areas where fracking happens are more prone to distantly triggered earthquakes.
Other research has also shown that the process alone can also cause them. A study published in Geology in March suggested that a magnitude 6.7 quake in Prague, Oklahoma, was likely triggered by wastewater injection.
While the study was able to find that fracking can lead to more earthquakes, scientists have not yet found why the faults near these sites are more vulnerable to triggered earthquakes.
[Image by Joshua Doubek via Wikimedia Commons]