Indiana has several faults, but, unlike California s famous San Andreas Fault, nearly all of our faults are buried and can t be seen at the surface. Researchers have been able to map some faults in Indiana using evidence found in rocks from oil and gas wells and by employing a method called reflection seismic profiling. This method involves recording man-made vibrations reflected off layers of rock below the surface. Most of the faults that have been mapped in Indiana are located in the southwestern corner of the state. These faults extend into Illinois and are collectively known as the Wabash Valley Fault System.
Normal faults form when the crust is being pulled apart instead of being compressed as it is now.
These mapped faults are unlikely candidates for future movement. This depth and the nature of the rock layers at that depth have limited the ability of seismologists to successfully map earthquake-generating faults using reflection seismic profiling. Much more research is needed before we will know the full extent of faulting beneath Indiana and the potential for movement along those faults.