publication . Article . Other literature type . 2001

Sinking Mafic Body in a Reactivated Lower Crust: A Mechanism for Stress Concentration at the New Madrid Seismic Zone

Kellogg, Louise; Pollitz, Fred F.; Bürgmann, Roland;
Open Access
  • Published: 01 Dec 2001
Abstract
We propose a geodynamic model for stress concentration in the New Madrid seismic zone (NMSZ). The model postulates that a high-density (mafic) body situated in the deep crust directly beneath the most seismically active part of the NMSZ began sinking several thousands of years ago when the lower crust was sud-denly weakened. Based on the fact that deformation rates in the NMSZ have accel-erated over the past 9 k.y., we envision the source of this perturbation to be related to the last North American deglaciation. Excess mass of the mafic body exerts a downward pull on the elastic upper crust, leading to a cycle of primary thrust faulting with secondary strike-sl...
Subjects
free text keywords: Geochemistry and Petrology, Geophysics, Deformation (mechanics), Thrust fault, Mafic, Geology, Continental crust, Crust, Deglaciation, Seismology, Density contrast, Fault (geology), geography.geographical_feature_category, geography
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