Government scientists say more than a dozen regions in the United States have experienced a rise in man-made earthquakes in recent years.
A report released Thursday found that 17 areas in eight states have seen small quakes triggered by oil and gas drilling. They include parts of Alabama, Arkansas, Colorado, Kansas, New Mexico, Ohio, Oklahoma and Texas.
The U.S. Geological Survey says most of the shaking is caused by the oil and gas industry injecting wastewater deep underground, which can activate dormant faults. A few cases stemmed from hydraulic fracturing, or fracking.
The agency plans to study how often man-made quakes are expected to occur in the next year and how much shaking they would produce.
Scientists released the report at an earthquake meeting in Pasadena, California.