"All of a sudden, I was awakened by this rumbling shaking," McMurtry said.
"My bed is an older wood frame bed, so the bed started to creak and shake, and it was almost like somebody was taking my mattress and moving it back and forth."
In Louisville, Kentucky, the quake caused some bricks to fall off a building near downtown. Television video showed the bricks strewn in the street.
The quake also shook skyscrapers in downtown Indianapolis, about 160 miles (257 kilometers) northeast of the epicenter.
New Madrid Zone
Today's quake is believed to have involved the Wabash fault, a northern extension of the New Madrid fault that creates a seismic zone in the Midwest, said U.S. Geological Survey geophysicist Randy Baldwin. (Get an overview of plate tectonics.)
In 1811 and 1812, the New Madrid fault produced a series of earthquakes estimated at magnitude 7.0 or greater said to be felt as far away as Boston, Massachusetts.
Experts say that with the much higher population in the Midwest, another major quake along the New Madrid fault zone could destroy buildings, bridges, roads and other infrastructure, disrupt communications, and isolate areas.
(Read "Big Earthquake Could Devastate U.S. Midwest, Experts Warn" [April 12, 2006].)
The last earthquake in the Wabash region to approach the severity of today's temblor was a magnitude 5.0 quake that shook a nearby area in 2002, Baldwin said.
"This is a fairly large quake for this region," he said. "They might occur every few years."
The strongest earthquake on record with an epicenter in Illinois occurred in 1968, when a magnitude 5.3 temblor was recorded about 75 miles (120 kilometers) southeast of St. Louis, according the USGS.
The damage from that event was minor but widespread and there were no serious injuries.
