Quakes Shake Midwest, Alaska

A rare earthquake struck northern Illinois early Monday, rattling windows and awakening residents across several states.

No injuries were reported from the quake, which happened about 1:11 a.m. CDT (2:11 a.m. EDT).

A few hours later, a powerful earthquake jolted Alaska panhandle residents out of their sleep early Monday, but no significant damage was reported there, either.

That quake happened at 1:50 a.m. Alaska time (5:50 a.m. EDT) and was centered beneath the ocean off the southern end of the panhandle, said Bill Knight, a scientist at the Alaska Tsunami Warning Center at Palmer. The center had calculated a preliminary magnitude of 7.0 but the U.S. Geological Survey later put the magnitude at 6.7.

Brian Lassige, a geophysicist with the U.S. Geological Survey in Colorado, said the Illinois quake was magnitude 4.5, and its epicenter was about eight miles northwest of Ottawa in northern Illinois, close to the village of Troy Grove.

Lassige said earthquakes in the area of northern Illinois are rare, but ones were recorded in 1881, 1912 and 1972. The rural area is about 70 miles west of Chicago.

Police received about 300 calls in a half hour after the shaker, reports Bernie Tafoya of CBS radio station WBBM-AM. Few callers guessed correctly that it was an earthquake.

"We have the big sand flat next to the house, and we thought that something was going on with them blasting down that sand flat," said one.

"The first thing I thought was a semi crashed into the building," added another man.

"We have tractors in the yard, and we thought maybe of the tractors jumped and hit the house," said a woman caller.

"Here in the station, it felt like an aircraft was about to crash right here," said Pattie Burke, a dispatcher for the Ottawa police.

The geological survey said the three-second quake happened at a depth of 3.1 miles in a geologic structure associated with the Sandwich Fault Zone. It was not connected with the New Madrid Fault farther south, which has been responsible for the Midwest's most serious earthquakes.

The Alaska jolt, capable of significant damage had it happened near populated areas on land, did not generate a tsunami or seismic sea wave, Knight said. Callers to the center reported only "items falling off shelves," he said.

"We're pretty lucky, I guess," said James D. See, police chief in Craig, a logging and fishing town about 60 miles northeast of the epicenter. A 6.1 magnitude temblor had shaken the town last July 12.

See said the quake, which seemed to last about 20 seconds, woke him up and knocked a picture off the wall but caused no other damage in his house.

Craig Nesbit, a spokesman for the Exelon Corp., which owns the Quad Cities, LaSalle and Dresden nuclear power plants in northern Illinois, said the Nuclear Regulatory Commission declared a low-level alert for them, although there appeared to be no damage.

"All of them were operating 100 percent, and no problems were reported, but we did a check of all safety systems," Nesbit said.