Seven million people live and work in areas of the central and eastern United States U.S. (CEUS) with potential for damaging man-made earthquakes, according to a new report from the U.S. Geological Survey (USGS).

In a few parts of this region, the chance of damage from all types of earthquakes is similar to that of natural earthquakes in high-hazard areas of California, the agency said.

For the first time, new USGS maps have identified potential ground-shaking hazards from both human-induced and natural earthquakes. In the past, USGS maps only identified natural earthquake hazards.

The report also provides a one-year outlook for the nation’s earthquake hazards.

“By including human-induced events, our assessment of earthquake hazards has significantly increased in parts of the U.S.,” said Mark Petersen, chief of the USGS National Seismic Hazard Mapping Project. “This research also shows that much more of the nation faces a significant chance of having damaging earthquakes over the next year, whether natural or human-induced.”

Oklahoma, Kansas, Texas, Colorado, New Mexico and Arkansas are the six states with the highest risk of induced seismicity. Of these, Oklahoma and Texas have the largest populations exposed to induced earthquakes.

“In the past five years, the USGS has documented high shaking and damage in areas of these six states, mostly from induced earthquakes,” Petersen said.

Induced earthquakes are those triggered by human activities such as injecting oil and gas wastewater into deep underground wells. Wastewater disposal is the primary cause of recent seismic events in many areas of the CEUS, the report said.

Many states are now regulating wastewater injection in an effort to limit the risk of earthquakes.