By Joy Hampton
The Norman Transcript
NORMAN — At 5:18 on Saturday morning an earthquake measuring 3.9 on the Richter scale shook the metro area. The epicenter was one mile east-southeast of Choctaw. A second smaller shake registered at 5:46 a.m. the depth of the primary quake was 3.1 miles.
According to the U.S. Geological Survey and the Oklahoma Geological Survey, the largest earthquakes to rattle the Sooner state had a magnitude of 5.6 and occurred on Nov. 6, 2011 about 21 miles north-northeast of Shawnee near Prague in Lincoln County. The second largest quake occurred on April 9, 1952 near El Reno in Canadian County with a magnitude of 5.5. All other quakes recorded in Oklahoma have been below 5.0 magnitude, based on
information provided by O.G.S.
Most earthquakes in North America east of the Rockies occur as faulting with bedrock and are usually miles deep, according to U.S.G.S.
“”There is evidence that some central and eastern North America earthquakes have been triggered or caused by human activities that have altered the stress conditions in earth’s crust sufficiently to induce faulting,” U.S.G.S. reports.
The Oklahoma Geological Survey maintains a website that maps Oklahoma earthquakes. According to data showing the last seven days of earthquakes, there is daily activity. From May 25 through Saturday, at least one earthquake has registered every day somewhere in Oklahoma, but most are below 3.0 magnitude.
Mapping shows a cluster of quakes in Central Oklahoma over the past seven days. For more information visit okgeosurvey1.gov.
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