Oil and gas fracking triggers 900 earthquakes a year in this US state"Oklahoma has been transformed from a seismic dead zone to a hotspot in less than a decade," according to a University of Southampton academic.[Collection]

"Oklahoma has been transformed from a seismic dead zone to a hotspot in less than a decade," according to a University of Southampton academic.http://www.ibtimes.co.uk/oil-gas-fracking-triggers-900-earthquakes-year-this-us-state-1658463