Buried electrical pathways across the US reveal new clues about Earth's interior and power grid risks
A solar storm like the one that caused a nine-hour blackout across Quebec in 1989 could have even more dramatic effects if it struck the eastern United States today. Now, scientists have developed new tools to detect these ...
Mapping Earth's hidden electrical underworld
After 18 years of work and measurements at over 1,800 locations across the country, the United States Magnetotelluric Array (USMTArray) has completed the first comprehensive survey of electrical properties beneath the continent. In the new study, scientists from the Center for Astrophysics | Harvard & Smithsonian (CfA) present a three-dimensional map tracing how electrical currents flow through underground rocks, fluids, and ancient geological formations, uncovering hidden pathways and structures that shape North America from below.
The USMTArray captures natural changes in Earth's electric and magnetic fields at the surface. Since mineral composition, fluids, and temperatures all affect how electricity moves underground, these measurements allow scientists to peer beneath the surface: from shallow layers of sediment to the deep, ancient roots that have anchored the North American continent for over a billion years.
"Magnetotelluric data, which measures natural electric and magnetic field variations on the Earth's surface to map subsurface electrical resistivity, responds very strongly to things like fluids and melt," said Anna Kelbert, an Earth Science Project Scientist at the CfA and the lead author of the new paper published in Reviews of Geophysics.
Over the course of nearly 20 years, scientists installed and collected data at more than 1,800 magnetotelluric data stations around the country. The measurements collected have allowed scientists to develop new tools that can detect solar storms before they strike, helping to determine locations most at risk for negative impacts. Credit: Adam Schultz, Oregon State University
Coronal mass ejections (CMEs) move from the surface of the sun toward Earth through space. Top: CME is generated as an outflow of plasma and magnetic fields from the sun, moving through space to Earth over a matter of hours. Bottom: The magnetic fields of the CME and outflowing solar wind interact with Earth’s magnetic field, which shields it from greater effect. This interaction causes the auroras at the poles. Credit: Hayley Bricker/EarthScope
The Northern Lights, also known as the Aurora Borealis, are more active when there are solar flares on Earth's sun, or when an intense coronal mass ejection forces plasma from the sun into space. That same ejection can cause geomagnetic storms on Earth, which can in turn cause damage to Earth's electrical grid. Scientists from the USMTArray project have collected data over nearly 20 years to develop new tools that can predict where and when these storms will strike. Credit: U.S. Geological Survey