In a study to be published in the Bulletin of the Seismological Society of America on Tuesday, the scientists presented “several lines of evidence [that] suggest the earthquakes in the area are directly related to the disposal of wastewater” deep underground, according to a BSSA press release. Fracking and conventional natural gas companies routinely dispose of large amounts of wastewater underground after drilling. During fracking, the water is mixed with chemicals and sand, to “fracture” underground shale rock formations and make gas easier to extract.
The USGS research is just the latest in a string of studies that have suggested the disposed water is migrating along dormant fault lines, changing their state of stress, and causing them to fail.
Scientists Find 'Direct Link' Between Earthquakes And Process Used For Oil And Gas Drilling | ThinkProgress