HISTORIC buildings would crumble, highway overpasses would collapse, houses would be jarred off their foundations and dams, including possibly Lake Hefner's, would burst, sending walls of floodwater surging across the landscape.
A recent swarm of minor earthquakes has left Oklahomans unsettled, and while experts say the chances of a large, devastating quake happening here are remote, a big one is not out of the question. For the past several weeks, the state has felt an average of 12 quakes a day, many in the Oklahoma City area.
“It's rare for swarms to produce a large earthquake, but it's hard to say anything is for certain,” said Austin Holland, of the Oklahoma Geological Survey.
In November 2011, a 5.6 magnitude quake near Prague buckled U.S. 62 in several places, damaged 14 homes and collapsed a tower on Benedictine Hall at St. Gregory's University in Shawnee.
The quake was the largest recorded in state history, matching the April 9, 1952, El Reno earthquake that toppled chimneys and smokestacks, cracked and loosened bricks on buildings, broke windows and dishes and produced a 49-foot crack in the state Capitol in Oklahoma City. Damage from the 1952 quake was reported as far away as Iowa, Nebraska, Missouri and Texas.
By Oklahoma's own measure, any seismic event measuring 5.5 magnitude or greater is considered a severe earthquake. At that strength, home foundations can crack and large church bells ring on their own, according to the state's hazard mitigation plan.
An earthquake between magnitude 6.2 and 6.5 would partially collapse buildings, make cars difficult to steer and possibly alter the temperature and flow of springs and wells.
At magnitude 6.6 or greater, the state plan anticipates widespread destruction and panic. Should there be a breach of the 70-year-old Lake Hefner dam, water would flow northeast, flooding homes, commercial buildings and Mercy Hospital Oklahoma City before reaching the Cimarron River on the north side of Guthrie. Even a small earthquake in the right location could cause a dam to begin leaking and eventually fail, according to the state plan.
Such an earthquake also could cause extensive damage and possibly injuries and death from falling debris. Traffic would probably be disrupted not only for day-to-day needs but also for critical emergency services like police, fire and ambulances. School bus and mail routes also would be affected. Power and water outages could occur, causing food to spoil. Broken sewer lines could create sanitation problems. Schools, hospitals, grocery stores and other economically important facilities likely would be damaged and closed for extended periods. Employment would be affected because of businesses being closed due to the damage and loss of business.
Despite the potential for chaos, emergency response officials acknowledge the state is woefully unprepared.
On its list of disaster priorities, Oklahoma ranks earthquakes at No. 11, behind tornadoes, winter storms, sink holes, flooding, wildfires, high winds, drought, thunderstorms, lightning and extreme heat.
The amount of money the state allocates toward mitigation is based on the list.
“We don't think Oklahoma when we think earthquakes, and that is this uphill challenge that we face,” said Jim Wilkinson, of the Central U.S. Earthquake Consortium, a group dedicated to reducing the number of deaths, injuries, property damage and economic losses resulting from earthquakes. “There is a reason we need to be planning because the scale may not be as high, but nothing is out of the question.”
The earthquake consortium, of which Oklahoma is a member, has been stressing the need for the state to review building inspection procedures, improve public education regarding earthquakes and provide additional first responder training, Wilkinson said.
But, he noted, this isn't California, where there is a history of such quakes and elected officials and the public are more responsive to such requests.
“The dynamics of preparing for an earthquake, especially in this part of the country, are especially difficult,” Wilkinson said
Oklahoma Emergency Management Agency spokeswoman Kelly Cain says a new state disaster mitigation plan is in the works. The state last published a plan in June 2010, just as the recent swarm of about 6,000 earthquakes — half in the Oklahoma City area — began.
Of earthquakes measuring magnitude 4.0 or higher, the state has gone from averaging between one and three per year for the past three decades to about 40 a year since 2009. This year alone, the state has had more than 2,700 quakes.
While the number of earthquakes in Oklahoma is up, funding for earthquake research across the country is down, Wilkinson said. The budget is shrinking at the U.S. Geological Survey, the federal agency charged with earthquake monitoring. Much of the earthquake research is being done by a minimal staff.
“It essentially comes down to what we call the policy of disasters,” Wilkinson said of the tendency of governments to focus on recovery instead of preparedness. “Whatever was the latest and greatest is the one we want to take care of, which is really backward.”
A rocky start
In Oklahoma, efforts to improve the state's earthquake response plan are barely off the ground, said Bonnie McKelvey, an Oklahoma City Emergency Management Department employee who serves as state's earthquake program manager.
The state is trying to put together a committee of volunteers to review preparedness and response measures.
That includes mapping areas of the state most vulnerable to earthquake damage and training emergency workers how to react in the wake of such an event.
The ability to know and map which areas of the state are most likely to experience widespread destruction and need the most help could be critical to saving more lives, McKelvey said.
It also would be the committee's job to evaluate the structural integrity of buildings to know which would be good candidates for seismic retrofitting and which wouldn't. The effect of a severe earthquake on state-owned property and critical facilities is largely unknown.
It's uncertain what damage police and fire stations, hospitals and other emergency operations centers might sustain that could cripple their ability to respond to such an event. Masonry structures that are not reinforced would be expected to sustain heavy damage. Also of particular concern are bridges and highway overpasses undergoing repair or replacement. Many of the state's key highway bridges remain vulnerable. The same is true for many of the state's dams and school buildings.
“I don't have a real good sense of how well our buildings would hold up,” McKelvey said. “My guess is we would have a lot of buildings with some damage just because of a lot of our buildings are older, but that's just an educated guess.”