But the authors of the new study focus on the significantly larger and delayed events in Prague, which they wrote "necessitate reconsideration of the maximum possible size of injection-induced earthquakes, and of the time scale considered diagnostic of induced seismicity".

BBC: Oklahoma earthquake linked to oil extraction wastewater

The strongest tornado, rated a maximum EF5 on the Fujita Tornado Scale, tracked for nearly an hour and a half along a 38-mile path from Chickasha through south Oklahoma City and the suburbs of Bridge Creek, Newcastle, Moore, Midwest City and Del City.

CNN: Oklahoma City area was hammered by EF5 tornado in 1999