5.6 Quake Shakes Oklahoma Series of temblors rattles state more accustomed to tornadoes By Newser Editors and Wire Services Posted Nov 6, 2011 5:46 AM CST 9 comments Comments A 5.6 earthquake was the strongest so far in a series of earthquakes to shake Oklahoma this weekend. (USGS) (Newser) – A magnitude 5.6 earthquake last night was the strongest in a series that shook Oklahoma—a state more accustomed to tornadoes—cracking buildings, buckling a highway, and rattling nerves. The 5.6 quake was the state's strongest ever and shook a college football stadium 50 miles away, while another of lesser intensity struck before dawn today. "That shook up the place, had a lot of people nervous," Oklahoma State wide receiver Justin Blackmon said of the quake, the strongest of a series that began hours earlier. "It was pretty strong." The 5.6 earthquake was centered near Sparks, 44 miles northeast of Oklahoma City, and could be felt as far away as Tennessee and Wisconsin, according to reports received by the US Geological Survey. A magnitude 4.7 quake early yesterday was felt from Texas to Missouri. The USGS said the latest quake hit at 3:39am today, measuring 4.0 in magnitude and centered 36 miles east of Oklahoma City. Oklahoma typically has about 50 earthquakes a year, but a swarm of quakes east of Oklahoma City contributed to a sharp increase. Researchers said 1,047 quakes occurred last year, prompting them to install seismographs in the area. A cause of the uptick wasn't known.