In the United States, massive injections of wastewater from the oil and gas industry are likely to have triggered a sharp rise in earthquakes in the state of Oklahoma. Researchers say there has been a forty-fold increase in the rate of quakes in the US state between 2008-13.The scientists found that the disposal of water in four high-volume wells could be responsible for a swarm of tremors up to 35 kilometres away. Their research has been published in the journal, Science.