by Emil Morhardt
The seismicity induced by oil and gas operations in Oklahoma generally appears to be caused by reinjection of wastewater coming out with oil and gas rather than the increase hydraulic pressure from fracking directly. Not so in western Canada where much less wastewater is produced and injected, but there is nevertheless considerable induced seismicity tightly clustered in space and time near hydraulic fracking sites, according to Xuewei Bao and David W. Eaton (2016) writing in Science.
The figure from the paper (above) shows locations of seismicity in northwestern Alberta, anda from 1985-2016. The locations of the largest earthquakes are shown by date. Continue reading