The Midwest is quickly taking over California's reputation as the earthquake capital of the United States, and there's speculation the cause may not be a natural one.
Last year, the state of Oklahoma experienced 585 earthquakes of 3.0 magnitudes or higher, which is more than in the past 35 years combined.
Resident Sandra Ladra experienced the strongest – a 5.6 that hit the town of Prague in 2011.
"It was hard to [believe] because I had never been in anything like that."
A rock that fell from her fireplace injured her leg and shattered her sense of safety.
"If you don't feel safe in your home, what do you do?"
Since late 2009, the US Geological Survey (USGS) found Oklahoma has had 300 times more earthquakes than in previous decades.
The latest study says 300 million-year-old fault lines have been reactivated and are capable of producing a 6.0 magnitude quake.
"There are many old buildings that are not built to withstand 6.0 magnitude earthquakes, and that is part of the reason for the study – to identify regions most likely able to produce a size-six earthquake and how that may affect infrastructure in the buildings in the region," says Dan McNamara of the USGS.
Mr McNamara's research did not focus on a cause, but a 2014 study posted online in Science connected thousands of small earthquakes to oil and gas production. The study linked the increase in seismic activity to the process of pumping highly pressurised waste water into the ground – a by-product of fracking.
Kim Hatfield with the Oklahoma Independent Petroleum Association says the science to prove a definitive link simply isn't there.
"Coincidence is not correlation," she says. "This area has been seismically active over eons. The fact that this is unprecedented in our experience doesn't necessarily mean it hasn't happened before."
But it isn't slowing down. Scientists say the number of quakes so far this year is on track to set a new record.
CBS News
source: newshub archive
