Short Note: Magnitude Scaling of Prehistorical Earthquakes in the Wabash Valley Seismic Zone of the Central United States

Abstract

The moment magnitude determination for prehistorical earthquakes in the Wabash Valley seismic zone traditionally has relied on modified magnitude-bound liquefaction curves. The calibration of the moment magnitude and maximum distance to surface evidence of liquefaction curve for the central United States depended, in part, on the scaling of the 31 October 1895 earthquake as an M 6.8 event. Returning the M of the 1895 earthquake to a previously accepted value range of M 5.9 to M 6.2, and permitting the distance between the epicenter and the resulting liquefaction sites to vary, lowers the M of the prehistorical earthquakes by at least 0.6 units.