UP AND DOWN: Earthquakes rose, then abruptly dropped after wastewater injection stopped in one area of the Fayetteville shale gas exploration zone.
Credit where due for Arkansas. The New York Times Thursday reported
on the U.S. Geological Survey's release of a comprehensive assessment of the link between earthquakes
and oil and gas operations.
Arkansans have known for a long time of the correlation between fracking
— particularly the waste injection wells that are a byproduct — and seismic activity. That might seem unremarkable. But it's not. The government of Oklahoma
, which has had far worse earthquake activity, has just this week acknowledged there's some science behind the correlation of drilling and earth shaking.
Arkansas got a plug for good practices.
Asked about the report, Lawrence E. Bengal, director of the Arkansas Oil and Gas Commission, also pointed to what his state had already done, after a surge in earthquakes north of Little Rock in 2010 that made the state second only to Oklahoma in induced quakes.
The commission imposed a moratorium “prohibiting the drilling of any new disposal wells in the area where the earthquake activity had occurred,” Mr. Bengal said, ordered the four active wells in the area plugged and ruled that seismic activity must be taken into account when allowing new disposal wells in other parts of the state.
More regulation can be done. That, of course, is controversial anywhere, particularly in states with political leaders opposed to government regulation. Hint hint.
Risks in certain areas and predicting future quakes aren't easy matters.
“Difficulties in assessing seismic hazard arise from a lack of relevant technical information on human industrial activity (that is, pumping data for injection wells),” the report said. However:
Mr. Petersen noted that wastewater disposal and related earthquakes “fluctuate year by year based on economic and policy decisions, which are very difficult to predict.” In fact, the report shows that in places where wastewater injection stopped, earthquake frequency fell to near zero — notably, in central Arkansas since 2011 and in an area north of Denver in the 1970s.