For the first time, the U.S. Geological Survey is pinpointing the places where quakes induced by human activity as well as natural seismicity are most likely to occur this year.
The map released today dramatically raises the earthquake risk assessment for areas of Oklahoma, Kansas, Texas, Colorado, New Mexico and Arkansas, primarily due to seismic activity triggered by injecting wastewater deep underground.
Wastewater injection is often associated with the oil and gas extraction method known as hydraulic fracturing, or fracking. However, the USGS says fracking fluid typically makes up less than 10 percent of the injected wastewater. Most of it is saltwater that’s brought up as a byproduct during the oil and gas production process. To avoid polluting freshwater sources, the undrinkable water is typically pumped deep underground over the course of years or decades..
Previous studies have shown a link between wastewater injection and the increased incidence of quakes in Oklahoma. Such quakes aren’t catastrophic, but they do cause damage to buildings – and that’s why they were included in the newly released assessment.
“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 news release.