Geology experts: Indiana quakes possible due to seismic zone

TERRE HAUTE, Ind. (AP) – Indiana geology experts say the state isn’t immune to earthquakes due to southwestern Indiana’s position over the Wabash Valley Seismic Zone.

The Tribune-Star reports that the Wabash Valley zone bumps up against the South Central Illinois and New Madrid seismic zones. The New Madrid zone was the site of severe quakes in 1811 and 1812.

“The 1811 to 1812 quakes were substantial,” said Indiana State University geology professor Tony Rathburn. “If that happened today, it would cause an indescribable amount of damage.”

Walter Gray, educational outreach coordinator with the Indiana Geological Survey, says Wabash Valley has seen fewer earthquakes since the New Madrid temblors, but that they’ve been more energetic.

In 2008, a magnitude-5.4 earthquake struck northwest of Evansville. A magnitude-4.6 quake happened in 2002 in Posey County near Evansville.

Smaller earthquakes happen somewhat often, but people can’t usually feel quakes with magnitudes less than 3.5.

“The biggest hazard is that the frequency of earthquakes is so low that Indiana inhabitants become complacent,” Gray said.

Gray will give public demonstrations using an earthquake simulator on Wednesday at Indiana State University. Simulated magnitudes range from 3.0 to 7.0.