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 vidence of liquefaction curve for the cen-tral 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.