Oklahoma Earthquake is the State’s Largest on Record So Far

The earthquake that rattled Oklahoma on Sept. 3 is the state's strongest on record. The U.S. Geological Survey (USGS) has updated the magnitude of the earthquake to 5.8, which makes it the largest recorded earthquake in the state so far.

The earthquake, which shook Pawnee, Oklahoma, was initially pegged at magnitude 5.6. According to the USGS, the change came after further analysis of seismic recordings, revealing that the quake had a bigger moment magnitude.

"Changes in estimated magnitude for an earthquake are common in the hours-to-days following the event, as more data are analyzed in greater detail than is possible in the first minutes after the earthquake occurs," USGS said in a statement.

USGS also updated another record of a previous earthquake that hit Prague in Oklahoma on Nov. 6, 2011 from magnitude 5.6 to 5.7. The two updates were based on in-depth studies of the long-period, globally-recorded seismic data for the two earthquakes with the use of consistent approaches and data sets.

"USGS analyses indicate that the two earthquakes are very similar in size - to within typically-cited uncertainties of 0.1 magnitude units," Gavin Hayes, USGS research physicist, said in a statement.

"However, the 2016 Pawnee event is slightly larger than the Prague earthquake in 2011."

Last week's Oklahoma earthquake in Pawnee County was felt over seven other states. According to Oklahoma Governor Mary Fallin, three homes in Pawnee were damaged and three buildings in the city sustained damages. Also, an inspection of state highway and turnpike bridges turned up, USA Today reports.

A USGS report released in March suggested that increased seismic activity could be linked to disposal wells that push waste water deep underground. Hydraulic fracturing is also said to trigger earthquakes. These activities are putting the central and eastern U.S. at risk of earthquakes similar in magnitude with those that hit high-hazard areas of California, USGS said.

According to a report from CNN Money, Oklahoma state officials shut down 37 of the state's 3,200 active disposal wells, which increased public concern that oil and gas drillings may be responsible for the earthquakes.