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The study was led by Anna Kelbert, an Earth Science Project Scientist at the Center for Astrophysics at Harvard & Smithsonian (CfA<\/a>).<\/p>\n It draws on data from the United States Magnetotelluric Array (USMTArray), an 18-year effort that collected measurements at more than 1,800 locations across the country.<\/p>\n Researchers used those observations to create the first comprehensive map of the electrical properties beneath the continental United States.<\/p>\n Mapping the USMTArray<\/p>\n Most people think of the ground as inert \u2013 something solid and static that simply holds everything up. The reality is far more complex.<\/p>\n Underground rocks, fluids, and ancient geological formations all conduct electricity to different degrees.<\/p>\n The way electrical currents move through them depends on mineral composition, temperature, and water content.<\/p>\n The USMTArray captured natural variations in Earth\u2019s electric and magnetic fields<\/a> at more than 1,800 measurement sites across the country.<\/p>\n Researchers then used those readings to build a three-dimensional picture of electrical resistivity stretching from shallow sediment layers down to the deep ancient roots that have anchored North America for more than a billion years.<\/p>\n Hidden pathways and structures<\/p>\n Magnetotelluric data responds especially strongly to fluids and molten material beneath the surface, giving scientists a very different way to study Earth compared to seismic imaging, Kelbert explained.<\/p>\n The result is a map revealing hidden pathways and structures shaping the continent from below. These include ancient subduction zones<\/a> marked by conductive graphite and sulfide minerals.<\/p>\n The map also reveals stable continental cores that have persisted for billions of years, along with geological features never before mapped at this level of detail.<\/p>\n When a geomagnetic storm hits, it does not just affect satellites and radio signals in the atmosphere.<\/p>\n Energy from the sun also drives electrical currents through the ground, and those currents can flow directly into power lines.<\/p>\n The 1989 Quebec blackout remains the clearest modern example of what that looks like in practice.<\/p>\n Storm-driven geoelectric fields overwhelmed the Hydro-Qu\u00e9bec power grid and left millions of people without electricity<\/a> for nine hours.<\/p>\n What fewer people realize is that during the same storm, geoelectric field amplitudes at a site in Maine reached 36.7 volts per mile (22.79 volts per kilometer) \u2013 a level far beyond what power systems are designed to handle.<\/p>\n Electric grid was not built for this<\/p>\n According to Kelbert, anything above about 1.6 volts per mile (one volt per kilometer) is considered a threat by the power grid industry.<\/p>\n \u201cFor anything like 20 V\/km, if the geoelectric field of that amplitude was oriented along a typical 200-km (124-mile) power line in Maine, we\u2019d be looking at voltages of 4,000 V,\u201d she said.<\/p>\n Engineers built power grids to handle alternating current<\/a>, not a sustained surge of direct current at that scale.<\/p>\n When that happens, expensive transformers \u2013 which can take months or even years to replace \u2013 can overheat and fail.<\/p>\n A blackout on the scale of the Quebec solar storm event, but spread across a larger and more interconnected grid, could leave major parts of the country without power for an extended period.<\/p>\n Before this project, scientists studying grid vulnerability had to rely on simplified, one-dimensional models of how electricity moves through the ground.<\/p>\n Those models treated the geology beneath the United States as if it were mostly uniform, even though underground conditions vary enormously from place to place.<\/p>\n The new data reveal something those simpler models missed entirely. Geoelectric hazards can change dramatically between locations just a few miles apart.<\/p>\n Two nearby towns can face very different levels of risk depending on the geology beneath them.<\/p>\n A rocky ancient formation conducts electricity very differently from a basin of sedimentary rock saturated with groundwater<\/a>.<\/p>\n That variation matters enormously when scientists try to predict where storm-related damage could be most severe.<\/p>\n A clearer picture of grid danger<\/p>\n Today, data from the USMTArray feeds into a real-time risk map managed by NOAA<\/a> and the US Geological Survey<\/a>, which monitors electric fields across the country as storms develop.\u00a0<\/p>\n For the first time, scientists and grid operators can pinpoint where the danger is concentrated with detailed, location-specific data.<\/p>\n That is a major improvement over relying on national averages that often hide local conditions and risks.<\/p>\n USMTArray map implications<\/p>\n The practical applications extend beyond solar storm<\/a> preparedness.\u00a0<\/p>\n Because the map tracks underground fluids and electrically conductive minerals, it could help scientists identify mineral deposits and geothermal energy sources.<\/p>\n Those underground heat resources are becoming increasingly valuable as the global energy transition accelerates.<\/p>\n But the map also tells a deep geological story. The three-dimensional model traces the paths of ancient landmasses that once collided and maps the stable cores of the continent that have barely changed in billions of years. <\/p>\n It also captures geological features that seismic methods alone cannot detect.<\/p>\n The work isn\u2019t finished, though. Mapping the hazard in real time is one thing. Acting on it fast enough to protect the grid is another.<\/p>\n \u201cThere is still a gap between knowing the geoelectric fields in real-time and using this information to make timely operational decisions. Prediction, not just detection, is the next frontier,\u201d Kelbert said.<\/p>\n The full study is published in the journal Reviews of Geophysics<\/a>.\u00a0<\/p>\n \u2014\u2013<\/p>\n Like what you read? Subscribe to our newsletter<\/a> for engaging articles, exclusive content, and the latest updates.<\/p>\n Check us out on EarthSnap<\/a>, a free app brought to you by Eric Ralls<\/a> and Earth.com.<\/p>\n \u2014\u2013<\/p>\n","protected":false},"excerpt":{"rendered":"A solar storm powerful enough to cause a nine-hour blackout across Quebec \u2013 exactly what happened in 1989…\n","protected":false},"author":2,"featured_media":448434,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[61,60,82],"class_list":["post-448433","post","type-post","status-publish","format-standard","has-post-thumbnail","category-science","tag-ie","tag-ireland","tag-science"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts\/448433","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/comments?post=448433"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts\/448433\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/media\/448434"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/media?parent=448433"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/categories?post=448433"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/tags?post=448433"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}![\"Over](\"https:\/\/www.newsbeep.com\/ie\/wp-content\/uploads\/2026\/05\/usmtarray-map_magnetotelluric-surveys_OSU_1s.webp\")
<\/a>Over the course of nearly 20 years, scientists installed and collected data at more than 1,800 magnetotelluric data stations around the country in the USMTArray. Credit: Adam Schultz, Oregon State University. Click image to enlarge.Solar storms and power grids<\/p>\n![\"Coronal](\"https:\/\/www.newsbeep.com\/ie\/wp-content\/uploads\/2026\/05\/coronal-mass-ejections_cme_usmtarray_illustration_Hayley-Bricker_1s.webp\")
<\/a>Coronal mass ejections (CMEs) move from the surface of the Sun towards Earth through space. Top: CME is generated as an outflow of plasma and magnetic fields from the Sun, moving through space to Earth and into the USMTArray over a matter of hours. Bottom: The magnetic fields of the CME and outflowing solar wind interact with Earth\u2019s magnetic field, which shields it from greater effect. This interaction causes the auroras at the poles. Credit: Hayley Bricker\/EarthScope. Click image to enlarge.USMTArray boosts threat level<\/p>\n