- © 2014 by the Seismological Society of America
Online Material: Tables of OIINK catalog information and focal mechanisms.
Although far away from active plate boundaries, continental interiors are seismically active and include significant seismic zones (Sykes, 1978). The best known of these zones in the central United States is the New Madrid seismic zone (NMSZ; Nuttli, 1973a, 1983). The NMSZ has been a particular focus of attention for seismic studies in the central United States due to the three large Mw>7.0 earthquakes in 1811–1812 (e.g., Nuttli, 1973a; Dunn et al., 2010; Page and Hough, 2014). However, there is evidence of significant potential for large earthquakes outside the NMSZ, such as in the Wabash Valley seismic zone (WVSZ; Nuttli, 1979; Obermeier et al., 1991; Munson et al., 1992; Pavlis et al., 2002; Herrmann et al., 2008; Yang et al., 2009; Hamburger et al., 2011), the region near Marianna, Arkansas, southwest of the NMSZ (Tuttle et al., 2006), the region around the Meers fault, southwestern Oklahoma (e.g., Luza et al., 1987; Kelson and Swan, 1990), and the region northwest of the NMSZ around the Ste. Genevieve fault zone (Heinrich, 1937, 1949; Nuttli, 1973b).
This study focuses on what we refer to as the Ste. Genevieve seismic zone (SGSZ), the seismically active region associated with the Ste. Genevieve fault zone (Fig. 1). The Ste. Genevieve fault zone is one of the northwest‐trending fault systems that cut across southwestern Illinois and eastern Missouri (Nelson, 1995; Marshak and Paulsen, 1996, 1997). It has been mapped for approximately 190 km along strike from the northeastern flank of the Ozark dome in southeastern Missouri into southwestern Illinois (Fig. 1) (Nelson and Lumm, 1985; Nelson, 1995; Harrison and Schultz, 2002).