Official: 40 to 50 buildings damaged in Oklahoma earthquake

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Official: 40 to 50 buildings damaged in Oklahoma earthquake

By JUSTIN JUOZAPAVICIUS

 

CUSHING, Okla. (AP) — Dozens of buildings sustained "substantial damage" after a 5.0 magnitude earthquake struck an Oklahoma town that's home to one of the world's key oil hubs, but officials said Monday that no damage has been reported at the oil terminal.

 

Cushing City Manager Steve Spears said 40 to 50 buildings were damaged in Sunday's earthquake, which was the third in Oklahoma this year with a magnitude of 5.0 or greater. No major injuries have been reported, and Spears said the damage included cracks to buildings and fallen bricks and facades.

 

Oklahoma has had thousands of earthquakes in recent years, with nearly all traced to the underground injection of wastewater left over from oil and gas production. Sunday's quake was centered 1 mile west of Cushing and about 25 miles south of where a magnitude 4.3 quake forced a shutdown of several wells last week. Some longtime Cushing residents said Monday they've become accustomed to the unsettled ground beneath their feet. Others shrugged it off as a cost of doing business living next to an oil hub.

 

Fearing aftershocks, police cordoned off older parts of the city about 50 miles northeast of Oklahoma City to keep gawkers away late Sunday, and geologists confirmed that several small quakes have rumbled the area. Spears said an assisted living community had been evacuated after damage was reported. The Cushing Public School District canceled Monday classes.

 

The Oklahoma Department of Transportation reported Sunday night that no highway or bridge damage was found within a 15-mile radius of the earthquake's epicenter.

 

The quake struck at 7:44 p.m. Sunday and was felt as far away as Iowa, Illinois and Texas. The U.S. Geological Survey initially said Sunday's quake was of magnitude 5.3 but later lowered the reading to 5.0.

 

"I thought my whole trailer was going to tip over, it was shaking it so bad," said Cushing resident Cindy Roe, 50. "It was loud and all the lights went out and you could hear things falling on the ground.

 

"It was awful and I don't want to have another one."

 

In recent years, Oklahoma regulators have asked oil and gas producers to either close wastewater injection wells or cut back on the volume of fluids injected. The reductions have generally led to a drop-off in quakes and their severity, though not always.

 

Oklahoma's strongest quake on record, a magnitude 5.8 temblor on Sept. 3, occurred in Pawnee, on the fringe of an area that had already restricted wastewater disposal. Shortly afterward, geologists speculated on whether the temblor occurred on a previously unknown fault.

 

Oklahoma Geological Survey geophysicist Jefferson Chang said Sunday's quake and several aftershocks have been occurring on a fault line located about 2 miles west of Cushing.

 

"The activity has been going on for the past year and a half or so," Chang said. "This is just a spike in the activity."

 

Cushing's oil storage terminal is one of the world's largest. As of Oct. 28, tank farms in the countryside around Cushing held 58.5 million barrels of crude oil, according to data from the U.S. Energy Information Administration. The community bills itself as the "Pipeline Crossroads of the World."

 

Cushing Assistant City Manager Jeremy Frazier said two pipeline companies had reported no trouble as of late Sunday but that the community hadn't heard from all companies. Gov. Mary Fallin tweeted that no damage was reported at the storage tanks at Cushing's oil storage terminal.

 

Some residents tried to resume normal lives Monday, treating the earthquake as more nuisance than calamity, even though the temblor could be a predictor of more to come.

 

"We live in Cushing," said resident Susie Wooten, who was taking pictures of the cracked bricks outside her dry cleaning business. "You can't blame the oilfields; we're on a major fault line."

 

For truck driver James Mutters, having oil tank farms so close to where he lives is a fact of life.

 

"If you live here, obviously you know about the oilfields," he said. "I drive a truck, so I need to have gas. You can run all the stuff you want from the sun, but most of the stuff has to be run off something."

 

According to USGS data, there have been about two dozen earthquakes in Oklahoma in the past week. When particularly strong quakes hit, the Oklahoma Corporation Commission directs well operators to cease wastewater injections or reduce volume.

 

"I was at home doing some work in my office and, basically, you could feel the whole house sway some," Spears, the Cushing city manager, said Sunday night. "It's beginning to become normal."

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Sean Murphy in Oklahoma City and Jill Bleed in Little Rock, Ark., contributed to this report.

 

-- © Associated Press 2016-11-08

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Geologists explain Oklahoma earthquakes, ponder 'unknown'

By ROXANA HEGEMAN

 

WICHITA, Kan. (AP) — Thousands of earthquakes have rattled Oklahoma and neighboring states in recent years, with the most significant portion traced to the underground injection of wastewater left over from oil and gas production. The latest strong temblor — a magnitude 5.0 — damaged dozens of buildings in Cushing, Oklahoma, but spared a major oil terminal and caused no major injuries.

 

Here's a look at earthquakes in Oklahoma and what the future may hold:

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WHY DOES OKLAHOMA HAVE SO MANY EARTHQUAKES?

Scientists have linked Oklahoma's earthquakes to the underground disposal of wastewater during oil and gas production. Virtually every well produces some water along with the oil and gas that is pumped out of the ground. But wells in Oklahoma bring up a lot more — as much as 10 to 50 barrels of water for every barrel of oil produced. That is far more water than is produced from wells in other U.S. energy producing areas like those in North Dakota where wastewater injection has not triggered earthquakes.

 

All that wastewater, along with a small amount of water used in the drilling process itself, is contaminated. To get rid of it without contaminating surface waters, producers have been injecting it using disposal wells drilled deep into the Arbuckle formation, a sandstone layer that underlies Oklahoma and southern Kansas.

 

But so much wastewater has now been injected into it that it has overloaded the formation. This "pulse of water" is now spreading out across the formation, changing the underground pressure and triggering earthquakes along what had been inactive, stable faults millions of years old.

 

"We have earthquakes telling us where the faults are," said Jeremy Boak, director of the Oklahoma Geological Survey.

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ARE THE OKLAHOMA EARTHQUAKES GETTING WORSE?

For about 100 years or so, there had been only two earthquakes that came close to a magnitude 5.0 in Oklahoma, said George Choy, a geophysicist with the U.S. Geological Survey. During the past five years, there have been at least four 5.0 or greater earthquakes — including the one Sunday that was the third such earthquake this year.

 

The number of Oklahoma earthquakes peaked in June 2015 and the amount of wastewater injection peaked in late 2014. The rate of earthquakes has been cut in half as producers have been decreasing the amount of water they had been injecting into the formation.

 

Magnitude 2.8 or greater earthquakes have decreased from 4.5 to 2.3 earthquakes per day in Oklahoma, Boak said.

"I would argue it is declining, even as we have these large earthquakes," Boak said.

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WHY HASN'T THERE BEEN MORE DAMAGE?

As a rule-of-thumb, it usually takes a 6.0 magnitude or greater earthquake in that part of the country before you can see major damage, said Rex Buchanan, director emeritus of the Kansas Geological Society.

 

But even then a lot depends on the earthquake's location and depth, the time of day, and the type of geology.

Sometimes a little bit of luck helps, too. Until now, Oklahoma's strongest earthquakes have registered in less-populated areas.

 

Cities built over hard bedrock shake more than those built on alluvial areas with more sand and gravel.

"What matters here is not how much energy was released by the earthquake but how intensely does the ground shake," Buchanan said.

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WHAT DOES THE FUTURE HOLD?

Oklahoma and its neighboring states can expect more earthquakes for at least another year — and probably for several years — even after wastewater injection into the Arbuckle formation ends, Boak said.

 

It takes a while for the pressure in that wastewater to reach equilibrium and spread out enough so it is not sending those pulses of pressure in such concentrated areas, and triggering earthquakes.

 

"We are still learning about this stuff every day, Buchanan said. "So it is an unknown."

 

-- © Associated Press 2016-11-08

[Enoon]

"And so it was that they poisoned the land and the lakes and the rivers and the seas and the air, and verily they did cause the earth itself to split asunder, until there was nothing but desolation"

Edited November 8, 2016 by Enoon