Oil, Gas Drilling Wastewater Blamed for Earthquakes in Oklahoma

Wastewater from oil and natural gas drilling that’s pumped underground for disposal is more likely to trigger earthquakes than extracting the fuel by fracking, according to a new study.

The salty byproduct of hydraulic fracturing is often injected back underground where it penetrates fault lines and triggers seismic activity, said Mark Zoback, a geophysics professor at Stanford University and lead author of the study Thursday in the journal Science Advances. Fracking, in which fluids are forced underground to shatter rock and release oil and gas, presents a much lower risk, he said.