oil gas field frackingReuters

Lots of people are talking about a new study that links injecting wastewater from oil drilling into the ground with the largest earthquake instrumentally recorded in Oklahoma.

While the drilling technique referenced in the study did not itself involve fracking, wastewater injection is also a common part of fracking. 

Researchers from Oklahoma and Columbia universities found that over time, depositing used-up drilling fluid into the ground may have snapped geological tension that had built up near rural Prague, Oklahoma, causing a 5.7 quake that destroyed 14 homes and injured two.  

The authors also write that the number of large earthquakes in and around the center of the country has skyrocketed in recent years.

Here's exactly how they put it:

Earthquakes with Mw 5.0 [larger than 5.0 on the Richter scale — ed.] are rare in the United States east of the Rocky Mountains; however, the number per year recorded in the midcontinent increased 11-fold between 2008 and 2011, compared to 1976–2007. Of the total seismic moment released in the region, ~66% occurred in 2011 (from the GCMT).  

This echoes findings from a 2012 USGS study that found the frequency of earthquakes greater than or equal to Mw 3.0 had picked up six fold between 2001 and 2011 compared to the average for the 20th century.

The USGS authors say the increase "was almost certainly manmade," though add, "it remains to be determined how they are related to either changes in extraction methodologies or the rate of oil and gas production."

The authors of the Oklahoma study, meanwhile, are even more reluctant to say humans are responsible for the increase. 

Indeed scientifically proving an exact one-to-one connection is probably impossible.

But the new study provides further evidence that something new is going on.

Correction: The drilling technique discussed in the study did not involve fracking.