In March 11 IssueBy Derek AaronTimes Journal Reporter
With the recent rash of devastating and deadly earthquakes in Haiti, Chile and Turkey, thoughts of a similar earthquake in the United States are on the mind of many, including those right here in Kentucky where we are impacted by two major fault zones, New Madrid in Missouri and Wabash Valley in Illinois.
The New Madrid Seismic Zone crosses five state lines and cuts across the Mississippi River in three places and the Ohio River in two places.
Geologists and seismologists across the nation agree the zone could experience a large quake any time now. Just last week, a minor earthquake with a magnitude of 3.7, occurred at the fault, scientists said.
Quakes like last week's occur about once every five years, while the area can have hundreds of small quakes each year.
"Earthquakes are unpredictable," said Steve Oglesby, Kentucky's Earthquake Program Coordinator. "At best scientists make predictions based upon historical activity, but with so much uncertainty the possibility of a major earthquake effecting Kentucky cannot be taken for granted."
He said some scientists believe Kentucky is due for a major earthquake. 7.0 or higher.
Such a quake in the New Madrid Zone would impact our area as well as surrounding states with the devastation making the wake of Hurricane Katrina pale in comparison, experts agree.
The last Kentucky earthquake causing major damage was a 5.1 on the Richter scale near Sharpsburg in Bath County in 1980. That quake caused an estimated $3 million in damage, state records show.
According to the St. Charles County Division of Emergency Management in Missouri, the New Madrid fault averages about 20 measured events each month.
Every 18 months or so, the fault releases a quake of 4.0 or more, which is capable of local minor damage. Magnitudes of 5.0 or greater occur about once per decade, according to emergency officials, and can do significant damage
A damaging quake in this area, one 6.0 or greater, occurs every 80 years or so, with the last one in 1895, making the zone overdue for a strong quake.
A major earthquake, 7.5 or greater, happens at New Madrid roughly every 200- 300 years, with the last one in 1811.
The United States Geological Survey suggests a seven to 10 percent chance of a magnitude 7 or greater quake in the New Madrid zone in the next 50 years.
A New Madrid quake of this magnitude would be felt throughout half the United States and cause damage in 20 states or more, geologists say. In this event, Kentucky would likely see losses total in billions of dollars.
Barring a catastrophic quake, Russell County's Wolf Creek Dam would not be overly affected, according to Allison Jarrett, public affairs officer with the Corps of Engineers Nashville District.
"I do know that (geologists) have studied the impacts of a New Madrid earthquake originating from the fault line running through West Tennessee and have determined that it would not affect the stability of Wolf Creek Dam in any way," Jarrett said.
Jody Stanton, chief geologist for the Nashville District U.S. Army Corps of Engineers, said the massive New Madrid quake in 1811 gave an indication of what to expect at Wolf Creek if it were to happen again.
"The earthquakes in the winter of 1811 were the strongest ever felt in the eastern U.S.," Stanton said. "Based on eye witness accounts at the time, the area around Wolf Creek dam experienced shaking of Intensity VII on the Modified Mercalli scale, strong but incapable of causing damage to a structure as massive as the dam. Wolf Creek Dam is about 370 kilometers from the New Madrid earthquake zone, too far away to be damaged by any future quakes."
Back in April of 2008, many people across Russell County were awakened by an earthquake that rattled and shook homes across the region. The 5.2-magnitude quake, which caused more than 20 aftershocks, occurred in the early morning hours and was centered six miles from West Salem, Ill., and 66 miles from Evansville, Ind. according to the U.S. Geological Survey.
The earthquake took place in the Wabash Valley fault zone in southern Illinois and prompted the U.S. Army Corps of Engineers to investigate all dams in the Cumberland River watershed, including Wolf Creek Dam, which was then in the infant stages of its current rehabilitation project.
The Wabash Valley fault zone lies in Southern Illinois and is a lesser-known earthquake-producing fault system than the New Madrid fault zone of Southern Missouri but can still cause serious damage itself, experts say.
If experiencing an earthquake, the Kentucky Division of Emergency Management offers the following safety tips:
o Take cover under a sturdy desk, table or other furniture. If that is not possible, seek cover against an interior wall and protect your head and neck with your arms. Avoid danger spots near windows, hanging objects, mirrors or tall furniture.
o When in a high-rise building, move against an interior wall if you
you are not near a desk or table. Protect your head and neck with your arms. Do not use the elevators.
o When outdoors, move to a clear area away from trees, signs, buildings, or downed electrical wires and poles.
o When on a sidewalk near buildings, duck into a doorway to protect yourself from falling bricks, glass, plaster and other debris.
o If driving, pull over to the side of the road and stop. Avoid overpasses and power lines. Stay inside your vehicle until the shaking stops.
o When in a crowded store or other public place, move away from display shelves containing objects that could fall. Do not rush for the exit.
o When in a stadium or theater, stay in your seat, get below the level of the back of the seat and cover your head and neck with your arms.
o If you take cover under a sturdy piece of furniture, hold on to it and be prepared to move with it. Hold the position until the ground stops shaking and it is safe to move.