It’s well-established that injecting wastewater from oil and gas operations deep into the ground can cause earthquakes. New research shows that in some cases those earthquakes can keep happening long after an injection.
The practice of injecting wastewater has become more common across our region as oil and gas production has expanded. And the hotspot for injection-induced earthquakes in the Mountain West is Colorado.
The new study says, in some areas, this injected wastewater can contain high levels of salt and other compounds that make it very dense.
Ryan Pollyea, professor at Virginia Tech and lead researcher on the study, said “what we’re showing is that even after you stop pumping water underground, this high density wastewater will continue sinking and it can continue increasing fluid pressure to high enough levels that earthquakes can be triggered.”
And he said his research shows they can be triggered for up to a decade or more after the injections stop.
The report looked at the practice across the central US and Colorado. Pollyea said while Colorado does have injection-induced earthquakes the multi-year effect isn’t happening here yet. He said that’s because the wastewater is less salty here than in other parts of the country and doesn’t sink as deep.
This story was produced by the Mountain West News Bureau, a collaboration between Wyoming Public Media, Boise State Public Radio in Idaho, KUER in Salt Lake City, KUNR in Nevada and KRCC and KUNC in Colorado.