Can fracking cause earthquakes?

Hydraulic fracturing, commonly known as fracking, uses pressurized water to crack shale for access to oil and gas, which intentionally causes minuscule earthquakes — less than magnitude 1.  

From 1998 to 2008, annual earthquakes in Colorado increased with the rise in fracking wells. In the Denver Basin, where 90% of the roughly 15,000 gas wells are fracking sites, earthquakes greater than magnitude 2.5 were recorded in 2008, 2014 and 2016. 

While numerous studies have linked fracking to seismic activity, most of the larger fracking-related earthquakes are caused by the disposal of fracking wastewater by pumping it deep underground. The correlation between earthquakes and wastewater injection sites is especially strong in Oklahoma, Kansas and Texas. However, most wastewater injection wells do not cause earthquakes. 

Research suggests fracking itself triggers most of western Canada’s induced earthquakes, in contrast to the U.S., potentially due to geological differences.