New York Times: In Canada, a Direct Link Between Fracking and Earthquakes
In the Fox Creek area in Alberta, where oil and gas companies have been drilling in recent years into a formation called the Duvernay shale, earlier research had seen links between the earthquakes — all of which were minor and caused little damage — and fracking, rather than wastewater injection.
In their work, Dr. Eaton and Xuewei Bao, a postdoctoral researcher, looked into the links in more detail, analyzing seismic data from a series of quakes at Fox Creek in late 2014 and early 2015, and records from wells where fracking was occurring at the time.
They found two patterns to the seismicity. To the east in the fault zone, most of the earthquakes occurred during the fracking process itself, which lasted up to a month. To the west, there were few immediate quakes; they occurred intermittently over several months after the fracking ended.
