Slow deformation and lower seismic hazard at the New Madrid seismic zone

Global Positioning System (GPS) measurements across the New Madrid seismic zone (NMSZ) in the central United States show little, if any, motion. These data are consistent with platewide continuous GPS data away from the NMSZ, which show no motion within uncertainties, Both these data and the frequen cy-magnitude relation for seismicity imply that had the Largest shocks in t he series of earthquakes that occurred in 1811 and 1812 been magnitude 8, t heir recurrence interval should well exceed 2500 yea rs, Longer than has be en assumed. Alternatively, the Largest 1811 and 1812 earthquakes and those in the paleoseismic record may have been much smaller than typically assume d. Hence, the hazard posed by great earthquakes in the NMSZ appears to be o verestimated.