For the first time, the U.S. Geological Survey is including potential man-made seismic hazards - in particular, those caused by Hydraulic fracturing, aka fracking, on its maps that show earthquake risks.
"By including human-induced events, our assessment of earthquake hazards has significantly increased in parts of the U.S.," Mark Petersen, Chief of the USGS National Seismic Hazard Mapping Project, said in a press release.
Could Fracking Cause a Major Earthquake?
The new study also shows an increased risk for naturally occurring earthquakes, which is based upon new data obtained from earthquake faults since the last study in 2014. That study only considered natural earthquakes.
In the new study, Oklahoma and Texas are identified as the states with the largest populations at risk from human-induced earthquakes. Overall, about 7 million Americans live and work in parts of the United States where there's a potential for damaging shaking from such artificial seismic events.
In the fracking process, a mixture of water, chemicals and sand are injected at high pressure into rock formations to crack them and reach oil and gas deposits that were once difficult and costly to tap, Fracking provides about half of the nation's oil output, according to recent U.S. government report.
That's in addition to the slightly more than half of natural gas production that's coming from those wells.
How Well Can We Predict Earthquakes?
That supply of fossil fuel from what were once difficult-to-reach spots has transformed the energy industry and helped to drive down oil prices. But there's at least one downside - a startling increase in earthquakes in places such as Oklahoma.
Oklahoma experienced 907 magnitude 3+ earthquakes in 2015, compared to 585 in 2014 and 109 in 2013, according to a tally compiled by state officials. The state's own scientists have determined that the majority of recent earthquakes in central and north-central Oklahoma are very likely triggered by the injection of "produced" water in disposal wells. Produced water is brackish water that naturally occurs in oil and gas deposits, and is brought up along with the fossil fuels.
Here's a 2015 Stanford University study that explains how produced water causes quakes, and a U.S. Environmental Protection Agency website that details the fracking water cycle.
Fracking Triggers More Ohio Earthquakes