Glasgow Daily Times, Glasgow, KY

March 15, 2010

Expert talks earthquakes

Glasgow Daily Times

GLASGOW — Earthquakes happen every single day in countries all over the world.

On Friday March 5 there were 374 separate quakes, according to Michael May, Ph.D., P.G., from the Department of Geography and Geology at Western Kentucky University.

May spoke to members of the noon Horse Cave Rotary Club on March 8, on the topic of “Putting Recent Global Seismic Activity into Perspective.”

“People always ask, ‘Can we predict earthquakes?’ I can say with 100 percent certainty there will be an earthquake today, just don’t ask where,” he told club members.

There have been a number of earthquakes in the headlines recently, according to May. There was a 7.0 magnitude quake in Haiti on Jan. 12; a powerful magnitude 8.8 one on Feb. 27 and another registering 6.6 on March 5, both in Chile; a 7.0 quake in Japan on Feb. 26; one measuring 6.0 in Turkey on March 8; and a 3.7 magnitude earthquake along the New Madrid fault at the Mississippi River on March 1.

The strength of earthquakes is calculated on the Richter scale, a logarithmic measure ranging from 1 to infinity. The increase in magnitude from one number to the next is 31.5 times, according to May.

The 8.8 earthquake in Chile was 200 times more powerful than the one in Haiti, but the death toll was much higher than the result of the 7.0 magnitude quake in the Caribbean nation, he said. More than 200,000 people perished in Haiti, while only about 400 people died in the South American country.

One difference between the two is the way buildings are constructed, he said. Chile has tougher building codes because the largest quake ever recorded, a 9.5 magnitude one, struck the same area of that country in 1960.

“Chile recognized they needed to do something different with buildings,” May said. “What we build on and why we build the way we do (has to take into account the possibility of earthquakes). We have to go back and access older buildings.”

Haiti didn’t have the same level of building codes and the quake there caused much more structural damage and collapse.

“How could all these people perish?” he asked. Officials have to have better communication and education about how and where to build.

Kentucky has several seismic areas in and around the state. The largest is the New Madrid Seismic Zone. It is estimated that the probability of a magnitude 6 to 7 earthquake occurring in this seismic zone within the next 50 years is greater than 90 percent, according to the Kentucky Division of Emergency Management Web site.

The 3.7 magnitude quake in the New Madrid seismic zone on March 1 was a relatively small one. It normally takes a 3.0 or greater size earthquake for people to be able to detect it. Scientists have been monitoring the seismically active area between western Kentucky and Tennessee and eastern Missouri and Arkansas for many years.

In 1811-12, earthquakes in the New Madrid area registered at magnitudes of more than 8.4 on the Richter scale. One quake was so severe it caused the Mississippi River to run backwards, Reelfoot Lake in Tennessee to be formed and church bells rang on the East Coast.

“Paducah would have been ocean-front property if Mother Nature had her way,” May said.

Another area seismologists are watching is the Wabash Valley fault in southern Indiana and Illinois. It has been the most active seismic zone in the area for the last two generations, according to May. Owensboro and Evansville are at higher risk if an earthquake hits there because the buildings in both cities are built on alluvial soil deposited along the Ohio River, which makes them more susceptible to liquefaction.

According to May, liquefaction happens when the shaking of the ground separates the water from the soil holding it, causing the soil to behave like a dense liquid and will cause land to lose its ability to hold buildings up.

People should be prepared for earthquakes no matter where they live. May suggests families secure items around the house, such as china cabinets, have preparedness drills, know how to shut off utilities and have an emergency kit that includes at least three or four days of supplies. The kit should include water, non-perishable food, first aid, medications and a cell phone.