Stress evolution following the 1811–1812 large earthquakes in the

New Madrid Seismic Zone

 

Qingsong Li, Mian Liu, and Eric Sandvol

 

Department of Geological Sciences, University of Missouri, Columbia, Missouri, USA

 

Following a series of large (Mw = 7.0 – 7.5) earthquakes in the New Madrid Seismic Zone (NMSZ) in the central US during 1811 and 1812, more than a dozen moderate-size (M > 5) earthquakes occurred in this region, but mostly outside of the NMSZ fault zone. We have simulated the evolution of Coulomb stress and strain energy in the NMSZ and surrounding regions following the large 1811–1812 events in a three-dimensional viscoelastic finite element model. The results show that much of the stress and strain energy released by the large 1811–1812 events has migrated to southern Illinois and eastern Arkansas, consistent with the seismicity distribution. This inherited strain energy in these areas is capable of producing damaging (M = 6–7) earthquakes today.