Introduction: Seismicity, Quaternary Faulting, and Seismic Hazard

Abstract

More than 9 million people live within the boundary of the Illinois basin, most of them in four of the midcontinent's largest urban areas. The basin is characterized by moderate seismicity and abundant surface and subsurface geological and geophysical information. Therefore, the basin, which is directly northeast of the New Madrid seismic zone, is an excellent place to study the enigmatic geologic controls on cratonic seismicity, with potential applications to the basin and throughout the cratonic part of the midcontinent. The papers of this issue address the goal of seismic-hazard assessment in the Illinois basin by better characterizing earthquake sources, reporting the monitoring of earthquakes and deformation, and producing and disseminating seismic-hazard products.

Fault-Plane Determination of the 18 April 2008 Mount Carmel, Illinois, Earthquake by Detecting and Relocating Aftershocks

“…Previous studies suggested that those faults were high-angle normal faults that formed in late Pennsylvanian or younger and pre-Pleistocene time (Rene and Stanonis, 1995;Woolery, 2005). But origins of those faults still remain enigmatic (Marshak and Paulsen, 1996;Wheeler and Ravat, 2002). Only a few faults have been associated with known earthquakes.…”