Magnitude 3.8 Earthquake Rattles N. Central Indiana

The U.S. Geological Survey has lowered the estimated magnitude of an earthquake that shook parts of Indiana and four other states to magnitude 3.8.

The agency’s initial estimate of the quake’s strength was magnitude 4.2. The USGS said the 7:55 a.m. EST on Dec. 30 was centered about five miles south of Greentown in Howard County, about 50 miles north of Indianapolis.

The USGS said the quake was felt by people as far away as Illinois, Ohio, Kentucky and Wisconsin. Geophysicist Randy Baldwin said a quake of that magnitude would feel like a loaded truck passing by. No damage was immediately reported, and Baldwin said he didn’t expect any.

Howard County Chief Sheriff’s Deputy Steve Rogers said the department was bombarded by phone calls after the quake from people wondering if there had been an explosion. He said some people reported hearing a loud boom.

Baldwin said such booms are fairly common.

Indiana University geologist Michael Hamburger told Indianapolis television station WTHR that the temblor occurred in an area “that’s seismically very quiet.”

Baldwin agreed. There are no known fault lines in the area where the quake was centered, he said. “This is pretty unusual for the area,” he said.

Baldwin said two quakes had been reported within 60 miles of the epicenter in years past, including a 3.8 quake in 2004 and a 3.0 quake in 1990.

“They can happen pretty much anywhere” where stresses build up in the earth’s crust, he said.