A large November 2011 earthquake near Prague has been linked to human activity according to a USGS press release.
The 5.7 magnitude earthquake is thought to be the largest human-caused earthquake associated with wastewater injection.
Scientists had previously drawn a link between wastewater injection and a 5.0 magnitude quake that occurred on November 5, 2011 near active injection wells.
Now they suggest that the 5.0 quake caused a 5.7 magnitude quake less than 24 hours later which ruptured part of the Wilzetta fault system.
The first one is thought to have increased stresses in the fault system and the second to have set the stage for thousands of aftershocks.