At least nine earthquakes were reported Tuesday in central Oklahoma, some large enough to jolt people in the area, but no damage was reported.
The largest of the quakes was reported at 1:56 a.m. near Luther and woke people in the region. The 4.3 magnitude quake was followed by a 4.2 temblor at 5:16 a.m. in the same area. Other smaller earthquakes occurred throughout the day.
Quakes with a magnitude of 3 are among the smallest that are generally felt, while a magnitude 4 quake can do some damage.
Austin Holland, a seismologist with the Oklahoma Geological Survey, said Tuesday's string of quakes was different from other earthquakes that have struck the area in recent years. The largest earthquake in state history was a 5.7 magnitude quake in November 2011 near Prague.
“These certainly are very different earthquakes than what we've seen in the past,” Holland said. “These were very shallow. They are fairly rare. We haven't seen a series like this that has been so shallow with these size earthquakes.”
The quakes that hit the state Tuesday were centered four to five kilometers below ground. Most quakes are dozens of kilometers or more below ground.
Holland said shallower quakes are easier for people to feel, which might explain why so many people across central Oklahoma woke up during the two strongest quakes early Tuesday.
“The earthquake energy in the seismic waves decays rapidly as you get away from the epicenter,” Holland said. “It's kind of like if you throw a rock in a pond. The ripples get smaller as you move away from the center.”
“We are still looking into potential causes.”
It's also impossible to know whether the recent surge in the number of earthquakes in Oklahoma is a new normal or a temporary spike, Holland said.
“We can't forecast or predict earthquakes,” he said. “We have no idea if this is going to continue the way it has been or die off. I would assume this is some sort of temporary phase. But how long that temporary is, in geologic terms, that could be hundreds or thousands of years. Who knows what kind of time frame that might be?”
Robert Medley, Staff Writer
Be strong u guys who felt the earth quake, world pray for u. and how's you @greysonchance ? Take care and be safe, can't stop thinking of u— Em Chaenseu (@EmSabarini) April 16, 2013
Alright, Oklahoma. Get some rest. We're here for you if you need us. No matter the hour or how much it shakes.#earthquake— Red Cross Oklahoma (@redcrossokc) April 16, 2013
Well, that was certainly wild. #earthquake— Oklahoma City Zoo (@okczoo) April 16, 2013
We are not anticipating damage with this #earthquake.— Red Cross Oklahoma (@redcrossokc) April 16, 2013
Oklahoma and #earthquake are trending! Because we all have to verify that we're not insane when stuff starts shaking at 2 a.m.— Madi Alexander (@mlalexander9) April 16, 2013
For a second there I thought I had a Little to much vodka #OkEarthquake— Othoniel DeLeon (@OhhhTeee) April 16, 2013
Every time an #earthquake happens, my foundation guy gets a new boat.— Paul(@pmonies) April 16, 2013
That was rad. #earthquake— The Wedge Pizzeria (@wedgepizza) April 16, 2013
I would assume this is some sort of temporary phase. But how long that temporary is, in geologic terms, that could be hundreds or thousands of years. Who knows what kind of time frame that might be.”
Seismologist with Oklahoma Geological Survey