WASHINGTON (AP) A new federal study found that man-made earthquakes cause less shaking and in general are about 16 times weaker than natural earthquakes with the same magnitude.
These induced quakes are sometimes side effects of high-tech energy drilling from injecting wastewater underground.
U.S. Geological Survey geophysicist Susan Hough's study found that people report feeling the ground move from man-made quakes significantly less than those who experience more normal earthquakes of the same magnitude.
However, she said, within 6 miles of the fault, artificial and natural quakes feel pretty much the same.
The study is published Monday in the Bulletin of the Seismological Society of America. It is based on thousands of responses to the USGS "Did You Feel It" survey system after quakes in Oklahoma, Colorado, Arkansas, Texas and Ohio.