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New Geoelectric Hazard Map Available Adapted from Information by the U.S. Geological Survey The U.S. Geological Survey (USGS) has released a new report on geoelectric hazards for two-thirds of the contiguous U.S., spanning from the northeast to the west coast. This includes a map of voltages which would be affected by a geomagnetic superstorm. “The new voltage map is a critical step forward in our ability to assess the Nation’s risk to geoelectric hazards,” said Jim Reilly, USGS director. “This information will allow utility companies to evaluate the vulnerability of their power grid systems to magnetic storms and take important steps to improve grid resilience.” Geomagnetic storms are caused by the sun and solar wind surrounding earth. A magnetic disturbance during a geomagnetic storm generates electric fields in the planet’s crust and mantle which can interfere with the operation of grounded electric power grid systems. Geomagnetic storms don’t happen often, but when they are energetic enough, they can produce blackouts. One such storm caused a blackout of Quebec, Canada, in 1989. Similarly, the great magnetic storm of 1921, caused fires in telegraph stations used by railroad companies in New York City and other parts of the state. What is even more troubling is the thought of a rare magnetic superstorm, such as the Carrington event of 1859, which is the largest storm on record to hit the planet. According to a study by the National Academy of Sciences, if a superstorm were to hit our planet today, it could bring widespread blackouts, damage infrastructure, and have an economic impact of as much as $2 trillion. The new USGS research indicates geologic structure is also an important factor affecting storm-induced voltages on the power grid with the map showing a high hazard in the northern Midwest due primarily to electrically resistive rocks, particularly in the Piedmont Formation east of the Appalachian Mountains. The USGS Geomagnetism Program continuously monitors the earth’s magnetic field through a network of ground-based observatories. Data from these observatories, in addition to analysis of geoelectric hazards, are used to support mapping and directional drilling for gas and oil. Map of Northern United States showing geoelectri- cally induced voltage. Purple indicates the lowest voltage, and yellow the highest. DIR 16 JULY 2020 WorldWide Drilling Resource ®