IU Professor Says Earthquake an Oddity for Hoosier State

An Indiana University faculty member says he has learned to accept that earthquakes can take place in unexpected places.

But Geological Sciences Professor Michael Hamburger said there is a little known 10-mile area in Central Indiana called the Sharpsville fault, and believes that is where Thursday morning's magnitude 3.8 quake originated. The tremor located just north of Indianapolis was felt in four other states, including Illinois, but there were no injuries and very little damage was reported. Hamburger said pinpointing a source for the quake will take some time.

"One of the distinct problems is that earthquakes tend to happen fairly deep in the earth's crust, and the fractures that we see at the surface are quite superficial," Hamburger said. "They're mostly in sedimentary layers and we really need to do some imaging of the deeper architecture of the earth's crust in order to figure our what are the structures that are causing these earthquakes."

Hamburger said earthquakes in isolated places are not that unusual, and they are felt over a large area, citing the magnitude 5.2 Wabash Valley quake from April of 2008, when Illinois and at least 16 other states felt the impact. The majority of heavy activity comes from the Wabash Valley and New Madrid Seismic Zones.

Hamburger said he has heard only minor damage reports coming out of Indiana, including some of cracked pavement, but no structural damage. Despite the lack of earthquakes in Indiana, Hamburger said there are quake-resistant design codes for all of the state's public buildings.