Image of 3 million people in US at risk of man-made earthquakes this year
3 million people in US at risk of man-made earthquakes this year
Three million Americans, primarily in the Midwestern states of Kansas and Oklahoma, are at risk from human-induced earthquakes this year, according to a new report by the US Geological Survey.

The report, published on Wednesday, cites wastewater disposal from hydraulic fracturing or fracking as triggering the quakes.

The number of Americans affected this year by earthquakes is less than last year, when the USGS reported 7 million were at risk. Wastewater injection may have decreased in 2016 as a result of new regulations for its disposal, or slowed due to lower oil prices and less overall production.  

“Despite this decrease, there is still a significant likelihood for damaging ground shaking in the US in the year ahead,” said Mark Petersen, chief of the USGS National Seismic Hazard Mapping Project.

Pawnee, Oklahoma, was rocked by a 5.8-magnitude earthquake in September 2016, the state's largest ever recorded. Moreover, the state recorded the highest number of large earthquakes, of magnitude 4 or greater.

Fracking is the process of injecting liquid at high pressure into deep-rock formations to force open existing fissures and extract oil or gas. During the process, water fills pores in dormant faults, causing them to slip and unleash the quakes.

The forecast for the number of human-induced and natural earthquakes this year is "hundreds of times higher than before induced seismicity rates rapidly increased around 2008,” Petersen said.

“Millions still face a significant chance of experiencing damaging earthquakes, and this could increase or decrease with industry practices, which are difficult to anticipate.”

 Fracking is known to contaminate drinking water, pollute the air, and cause earthquakes, according to environmental groups, which want all fracking curtailed.