Oil-rich Oklahoma hit by 3.7 tremor

OKLAHOMA CITY, June 20 (UPI) -- A magnitude-3.7 earthquake hit central Oklahoma early Monday, the U.S. Geological Survey reported after several similar small tremors rocked the oil-rich state last week.

The USGS recorded the tremor near Fairview, Okla., around 3 a.m. Monday local time. A magnitude-3.2 quake struck near the border of Kansas late Sunday.

According to the Oklahoma Geological Survey at the University of Oklahoma, there were more than a dozen tremors recorded in the region since Friday.

A March report from the USGS found central U.S. states have experienced a dramatic increase in seismic activity over the past six years. The report said the disposal of oil and gas-related wastewater is the "primary reason" for the increase in seismic activity in the central United States. A weekly report on rig counts from oil services company Baker Hughes showed 58 rigs actively exploring for or producing oil or natural gas in the state.

USGS data show 888 tremors hit Oklahoma last year, a 51 percent increase from the previous year. The state recorded 34 seismic events in 2012.

Oklahoma is the No. 6 oil producer and No. 3 natural gas producer in the country. The state government earlier this year called on oil and gas producers to monitor wastewater in an effort to reduce seismic events.

A June survey from the Federal Reserve Bank of Kansas City, which extends coverage to Oklahoma, said economic growth for the state has outperformed North Dakota's, the No. 2 oil producer in the country, but not done as well as Texas, the No. 1 oil producer in the country.

Gov. Mary Fallin signed off on a 2017 budget earlier this month that she said closed a $1.3 billion budget gap, a shortfall that was the largest in state history.

No major damage was reported from the recent tremors.