From the journal Nature:
Two new studies provide the strongest evidence yet that oil and gas companies have caused a rash of earthquakes in the central United States by injecting wastewater into underground wells.
One study, in Science, finds that the extraordinary increase in quakes took place almost exclusively within 15 kilometres of such wells. The second, in Science Advances, confirms that most seismic activity in one state, Oklahoma, is linked to wells that are used to dispose of huge volumes of saltwater.
Both findings are a significant step forward in explaining why earthquake rates have soared in the central United States. In the 1970s, there were no more than 30 magnitude-3 or greater earthquakes per year in the region. That rate accelerated sharply in 2009, reaching more than such 650 quakes last year.
One study, in Science, finds that the extraordinary increase in quakes took place almost exclusively within 15 kilometres of such wells. The second, in Science Advances, confirms that most seismic activity in one state, Oklahoma, is linked to wells that are used to dispose of huge volumes of saltwater.
Both findings are a significant step forward in explaining why earthquake rates have soared in the central United States. In the 1970s, there were no more than 30 magnitude-3 or greater earthquakes per year in the region. That rate accelerated sharply in 2009, reaching more than such 650 quakes last year.