Recent studies of larger eastern North America earthquakes together with seismicity and focal mechanism studies in the New Madrid seismic zone permit estimates being made of static vertical displacements associated with the 1811 to 1812 New Madrid earthquakes. A comparison of observed and theoretically predicted vertical displacements is inconclusive due to the lack of detail in the historical record and the physical characteristics of the region where the earthquakes occurred.

On the other hand estimates are made of the seismic moment, fault area, and fault displacement. Given the inherent errors of the estimates, the parameters Ms, Mo, and fault area are consistent with the Kanamori and Anderson (1975) study of the interrelationship of these parameters for worldwide earthquakes. A stress drop on the order of 60 to 100 bars seems reasonable. These estimates will be useful for numerical ground motion estimation.

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