Insights Into Intraplate Stresses and Geomorphology in the Southeastern United States

Benjamin S. Murphy, Lijun Liu, Gary D. Egbert

Research output: Contribution to journalArticlepeer-review

Abstract

The stress field in the eastern United States is commonly considered to be broadly uniform and due to homogeneous far-field forces; however, modern and geologic stress indicators in this region show substantial heterogeneity. Using CitcomS to model stresses based on simple input density, temperature, and viscosity fields, we show that local isostasy is key in explaining the intraplate stress field in the southeastern United States. Crustal thickness variations appear to be most important in reproducing observations, although we slightly better match the observed stress field by including variable crustal viscosity informed by magnetotelluric imaging. Our results demonstrate that local gravitational body forces can substantially reorient far-field stresses and thereby influence patterns of intraplate seismicity. We also show that variable crustal viscosity encourages a steepening of isostatic topography in the southeastern United States; this observation suggests that a sharp boundary in crustal strength may be important in explaining the apparently long-lived Appalachian topographic escarpment.

Original languageEnglish (US)
Pages (from-to)8711-8720
Number of pages10
JournalGeophysical Research Letters
Volume46
Issue number15
DOIs
StatePublished - Aug 16 2019

Keywords

  • Appalachian topography
  • Blue Ridge Escarpment
  • Intraplate seismicity
  • Intraplate stresses
  • Passive margin escarpment
  • Southeastern United States

ASJC Scopus subject areas

  • Geophysics
  • Earth and Planetary Sciences(all)

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