Date of Award
Doctor of Philosophy
Maria Beatrice Magnani
The New Madrid Seismic Zone (NMSZ), central US. is a controversial midcontinental region where the occurrence of large magnitude historical and prehistorical earthquakes and the high level of instrumental seismicity, clash with the lack of evident surface and subsurface deformation and with slow geodetic rates. To unravel this apparent paradox locally and to contribute to the understanding of intraplate seismicity globally, I integrate new high-resolution seismic reflection data acquired as part of the Mississippi River Project, data acquired for the Meeman-Shelby Fault study, and existing seismic reflection data, to investigate the long-term deformation in the northern Mississippi Embayment. In particular this study focuses on the identification and characterization of the structures where Quaternary deformation is accommodated in the northern Mississippi Embayment, on the comparison of the newly discovered structures with those that are seismically active today, and on the analysis of the distribution of the Quaternary deformation with respect to the NMSZ. The results show that Quaternary deformation has been accommodated along adjacent faults additional to the NMSZ fault system, and that the NMSZ faults are virtually undistinguishable from quiescent faults, except for the instrumental seismicity. The distribution of Quaternary deformation extends beyond the footprint of the high-velocity lower crustal layer (i.e. “mafic rift pillow”), invoked by several geodynamic models as the possible feature capable of concentrating stress in this region and responsible for the seismicity in the central US. The long-term Quaternary deformation appears to be accommodated along pre-existing features predominantly associated with the Reelfoot Rift structure.
dissertation or thesis originally submitted to the local University of Memphis Electronic Theses & dissertation (ETD) Repository.
Guo, Lei, "Location And Characteristic Features of the Quaternary Deformation in the Mississippi Embayment from High-resolution Seismic Reflection Data" (2015). Electronic Theses and Dissertations. 1118.