Noble County quake early Saturday morning initially measured 5.1 by Ziva Branstetter, April 4, 2015, Tulsa World
A strong earthquake that registered up to 5.1 at some monitoring stations shook Noble County early Saturday.The earthquake was among at least 10 quakes over magnitude 3.0 in Oklahoma since Friday afternoon, according to the Oklahoma Geological Survey. OGS and the United States Geological Survey reported the earthquake at 8:21 a.m. Saturday as a magnitude 4.2. However, other monitoring networks and earthquake apps initially reported a magnitude between 4.6 and 5.1.
While it is not unusual for agencies to differ by a few tenths of a point in magnitude, the gulf between Saturday’s reported magnitudes raised eyebrows among some quake watchers. Scientists have different ways to calculate magnitude, and accuracy depends on factors including how close the monitoring equipment is to the epicenter.
On a Facebook page started by a group calling itself Stop Fracking Logan County, one woman posted: “What are they up to? Do they really believe they can hide a 5.1 magnitude earthquake from us?”
Scientific studies since the 1960s have shown that disposal wells used to dispose of oil and gas wastewater deep underground can cause earthquakes. Several studies by the USGS have concluded that Oklahoma’s huge increase in earthquakes during the past several years is linked to these wells. Mark Crismon monitors a seismograph on his property in Noble County as part of an Oklahoma State University research project. Crismon lives about 30 miles from the epicenter and said the quake appeared to be a 5.0.
“Boy, it was ugly. … It’s the biggest one I’ve ever seen since 2011,” he said.
A 5.6 magnitude earthquake struck the town of Prague on Nov. 5, 2011, destroying six homes and damaging nearly 200 more.
Crismon said his seismograph shows the vibrations caused by wastewater disposal wells in the area, which generally increases during weekends. He said he was awakened about 2:30 a.m. Saturday by a small earthquake. “It’s always on Fridays, Saturdays and Sundays,” Crismon said. “They hold the water until the enforcement people go home, and then they just blow it open.”
The epicenter of Saturday morning’s earthquake is in a rural area along Oklahoma 51 near the community of Lucien, about eight miles west of Perry.
Ruth Atterberry said she hasn’t heard any reports of damage in the community, which has about 75 residents.
“We just get these so often,” she said. “This one seemed comparable to what we’ve been feeling. It probably lasted longer.”
Atterberry said the reported intensity of earthquakes seems to vary widely. “It’s not so much how close you are but I guess how you are related to the fault line for that particular quake,” she said. Larry Sebranek lives four miles south of the epicenter and said the earthquake was “the strongest one I’ve felt so far. “
“I was sitting at the kitchen table and my kitchen chairs have rollers on them and you could actually feel the chair rolling back and forth across the floor.” [Emphasis]
Sebranek said his property wasn’t damaged but he is prepared in case a larger earthquake strikes in the future. He added earthquake insurance to his homeowner’s policy Friday. [Emphasis]