Oklahoma Earthquakes Rattle On

Government officials say the rate of earthquakes in Oklahoma of magnitude 3.0 or greater has risen significantly and that statistics show an increased chance for a magnitude 5.5 or greater quake in the state.

From January through May 2 the state recorded 145 earthquakes of magnitude 3.0 or greater, according to the U.S. Geological Survey and Oklahoma Geological Survey. The previous annual record for temblors of that size, set in 2013, was 109 earthquakes. The long-term average rate of magnitude 3.0 or larger earthquakes — from 1978 to 2008 — was just two per year.

Earthquakes of magnitude 2.5 to 3.0 are generally the smallest that are felt by humans, and damage is not likely at magnitudes below 4.0, officials say.

The pattern of stronger earthquakes in Oklahoma continued in September. A 3.6 magnitude earthquake struck on Sept. 22, a 3.7 magnitude earthquake struck on Sept. 24 and a magnitude 4.0 earthquake was recorded near Medford, on Sept. 17.

On Sept. 15, a magnitude 4.2 temblor occurred one mile southeast of Guthrie and a 3.2 magnitude quake struck about three miles south of Guthrie.

An earthquake with a magnitude of 3.7 rattled an area south of Perry, about 60 miles north of Oklahoma City, on Sept. 12. On Sept. 8, a magnitude 4.3 quake struck northern Oklahoma, near Medford. A 3.1-magnitude earthquake struck close to the same area on the previous evening.

Oklahoma Insurance Commissioner John Doak has encouraged the marketing and purchase of earthquake insurance, and Gov. Mary Fallin approved an emergency rule that requires all licensed property producers and adjusters to complete one hour of continuing education on earthquake insurance every two years. The rule becomes effective Jan. 1, 2015.

The strongest quake recorded in Oklahoma, a 5.7 magnitude temblor, hit near the town of Prague in November 2011. The USGS has suggested that the quake was associated with wastewater injection.

Associated Press reports contributed to this story.