<?xml version='1.0' encoding='utf-8'?>
<oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
  <dc:contributor>Greg M. Lucas</dc:contributor>
  <dc:contributor>Benjamin Scott Murphy</dc:contributor>
  <dc:contributor>Paul A. Bedrosian</dc:contributor>
  <dc:contributor>E. Joshua Rigler</dc:contributor>
  <dc:contributor>Anna Kelbert</dc:contributor>
  <dc:creator>Jeffrey J. Love</dc:creator>
  <dc:date>2021</dc:date>
  <dc:description>&lt;div class="article-section__content en main"&gt;&lt;p&gt;An analysis is made of Earth-surface geoelectric fields and voltages on electricity transmission power-grids induced by a late-phase E3 nuclear electromagnetic pulse (EMP). A hypothetical scenario is considered of an explosion of several hundred kilotons set several hundred kilometers above the eastern-midcontinental United States. Ground-level E3 geoelectric fields are estimated by convolving a standard parameterization of E3 geomagnetic field variation with magnetotelluric Earth-surface impedance tensors derived from wideband measurements acquired across the study region during a recent survey. These impedance tensors are a function of subsurface three-dimensional electrical conductivity structure. Results, presented as a movie-map, demonstrate that localized differences in surface impedance strongly distort the amplitude, polarization, and variational phase of induced E3 geoelectric fields. Locations with a high degree of E3 geoelectric polarization tend to have high geoelectric amplitude. Uniform half-space models and one-dimensional, depth-dependent models of Earth-surface impedance, such as those widely used in government and industry reports informing power-grid vulnerability assessment projects, do not provide accurate estimates of the E3 geoelectric hazard in complex geological settings. In particular, for the Eastern-Midcontinent, half-space models can lead to (order-one) overestimates/underestimates of EMP-induced geovoltages on parts of the power grid by as much as&lt;span&gt;&amp;nbsp;&lt;/span&gt;&lt;img class="section_image" src="https://agupubs.onlinelibrary.wiley.com/cms/asset/8e96158e-c9db-42eb-9c50-0ec06cf1a5bf/ess2899-math-0001.png" alt="urn:x-wiley:23335084:media:ess2899:ess2899-math-0001" data-mce-src="https://agupubs.onlinelibrary.wiley.com/cms/asset/8e96158e-c9db-42eb-9c50-0ec06cf1a5bf/ess2899-math-0001.png"&gt;1,000&amp;nbsp;volts (a range of 2,000&amp;nbsp;volts)—comparable to the amplitudes of the geovoltages themselves.&lt;/p&gt;&lt;/div&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.1029/2021EA001792</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>American Geophysical Union</dc:publisher>
  <dc:title>Down to Earth with nuclear electromagnetic pulse: Realistic surface impedance aﬀects mapping of the E3 geoelectric hazard</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>