Where was the 31 October 1895 Charleston, Missouri, Earthquake?

Abstract

We revisit the magnitude and location of the 31 October 1895 Charleston, Missouri, earthquake, which is widely regarded to be the most recent Mw 6 or greater earthquake in the central United States. Although a study by Bakun et al. (2003) concluded that this earthquake was located in southern Illinois, more than 100 km north of the traditionally inferred location near Charleston, Missouri, our analysis of exhaustively compiled macroseismic data supports the traditionally inferred location, with a preferred magnitude of Mw≈5.8 and a preferred magnitude range of 5.4–6.1. Our preferred magnitude is derived from comparisons with intensity distributions from the 1925 Mw 6.2 Charlevoix, the 1944 Mw 5.8 Massena, and the 1968 Mw 5.3 southern Illinois earthquakes, macroseismic data of which we also revisited in this study. Based on the distribution of liquefaction, reports of damage, and early aftershocks, we also explore possible rupture scenarios for the 1895 earthquake. Our preferred scenario involves unilateral rupture to the northeast on a (reactivated) northeast‐striking fault (or faults) coinciding with structures associated with the western limb of the Reelfoot rift, with an epicenter south‐southeast of Charleston, Missouri. Our results support the conclusion that within the Reelfoot rift, elevated seismic hazard is not restricted to the New Madrid seismic zone as conventionally defined but continues into the Charleston region in southeastern Missouri, where faults associated with the western edge of the Reelfoot rift appear favorably oriented for failure in the current stress regime.