Chapter 8
The First 3D Conductivity Model of the Contiguous United States
Reflections on Geologic Structure and Application to Induction Hazards
Anna Kelbert,
Paul A. Bedrosian,
Benjamin S. Murphy,
Anna Kelbert
Geomagnetism Program, United States Geological Survey, Denver, CO, USA
College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR, USA
Search for more papers by this authorPaul A. Bedrosian
Geology, Geophysics, and Geochemistry Science Center, United States Geological Survey, Denver, CO, USA
Crustal Geophysics, United States Geological Survey, Denver, CO, USA
Search for more papers by this authorBenjamin S. Murphy
College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR, USA
Search for more papers by this authorAnna Kelbert,
Paul A. Bedrosian,
Benjamin S. Murphy,
Anna Kelbert
Geomagnetism Program, United States Geological Survey, Denver, CO, USA
College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR, USA
Search for more papers by this authorPaul A. Bedrosian
Geology, Geophysics, and Geochemistry Science Center, United States Geological Survey, Denver, CO, USA
Crustal Geophysics, United States Geological Survey, Denver, CO, USA
Search for more papers by this authorBenjamin S. Murphy
College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR, USA
Search for more papers by this authorBook Editor(s):Jennifer L. Gannon,
Andrei Swidinsky,
Zhonghua Xu,
Jennifer L. Gannon
Search for more papers by this authorAndrei Swidinsky
Search for more papers by this authorZhonghua Xu
Search for more papers by this authorSummary
Estimation of ground level geoelectric fields has been identified by the National Space Weather Action Plan as a key component of assessment and mitigation of space weather impacts on critical infrastructure. Estimates of spatially and temporally variable electric fields are used to generate statistically based hazard maps and show promise toward monitoring and responding to geomagnetic disturbances in near real-time. One approach to geoelectric field estimation is to employ three-dimensional (3D) Earth conductivity models. These data-constrained conductivity models are the results of regional magnetotelluric inversions based primarily on NSF's Earthscope USArray impedances, which to date cover ∼ 60% of the contiguous United States. Here, we present the first-ever composite conductivity model of the contiguous United States and describe its compilation from 3D regional conductivity models, a global mantle conductivity model, offshore bathymetry, and sediment thickness data. We discuss structures within the conductivity model and how they relate to the complex geologic tapestry of the continent. Finally, we discuss the utility of this synthesis model for estimation and mitigation of geomagnetically induced currents.
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