14 DAY TRIAL // A paper published in this week's issue of the journal Science argues that, according to evidence at hand, wastewater injection has brought about an increase in seismic activity in Oklahoma, US in recent years.
The paper explains that, before 2008, when wastewater injection activities in this part of the country really took off, the state experienced an average of one earthquake whose magnitude was greater than 3.0 per year.
However, since the beginning of 2014 until present day, over 230 earthquakes whose magnitude exceeded 3.0 have been documented in this part of the United States. These earthquakes are now argued to have been caused by wastewater pumping.
“It really is unprecedented to have this many earthquakes over a broad region like this,” argues study co-author Geoffrey Abers of Cornell University.
Furthermore, “Most big sequences of earthquakes that we see are either a main shock and a lot of aftershocks or it might be right at the middle of a volcano in a volcanic system or geothermal system.”
Specialist Geoffrey Abers with Cornell University and fellow researchers explain that, after analyzing data concerning injection rates and liquid volumes at various sites, they found that wastewater pumping has the potential to foster earthquakes.
Interestingly enough, the scientists behind this research project argue that, according to evidence at hand, not all injection sites need be blamed for the increase in seismic activity documented in the state of Oklahoma.
On the contrary, they say that it's just a few sites that are causing these earthquakes. This is due to properties of the rocks these sites are made of and to the volumes of wastewater that are injected in them, the specialists write in the journal Science.
“The important thing is that we are seeing earthquakes that are much more widely distributed, much farther from wells and in a lot of different directions,” Cornell University researcher Geoffrey Abers said in a statement.
“Some of these earthquakes are as much as 20 miles (32.2 kilometers) away from what seems to be the primary wells that are increasing the pressure,” the study co-author went on to comment on the outcome of this investigation, as cited by Nature.
To make matters worse, chances are that, in the years to come, the number of wastewater injection sites in Oklahoma will up to a considerable extent. It is to be expected that, if Geoffrey Abers and his colleagues are right, this will translate into a further increase in seismic activity.