3 million Americans at risk from man-made earthquakes in 2017

Three million Americans, primarily in Oklahoma and Kansas, are at risk from man-made earthquakes this year, the U.S. Geological Survey said Wednesday.

That's the conclusion of a new report, which cites wastewater disposal from fracking as triggering the quakes. The number of Americans affected this year is less than last year, when the USGS said 7 million were at risk.

The 2017 forecast decreased compared to last year because fewer felt earthquakes occurred in 2016 than in 2015, the USGS said. Wastewater injection may have decreased in 2016 due to new regulations for its disposal, or slowed due to lower oil prices and less overall production.

“The good news is that the overall seismic hazard for this year is lower than in the 2016 forecast, but despite this decrease, there is still a significant likelihood for damaging ground shaking in the U.S. in the year ahead,” said Mark Petersen, chief of the USGS National Seismic Hazard Mapping Project.

Research also shows that an additional half million people face potential damage from natural earthquakes in 2017, which brings the total number of people at risk from both natural and human-induced earthquakes to 4 million.

This is the second year that the USGS has released an earthquake forecast

This research was published Wednesday in Seismological Research Letters.