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Geoelectric hazard maps for the continental United States

September 28, 2016

In support of a multiagency project for assessing induction hazards, we present maps of extreme-value geoelectric amplitudes over about half of the continental United States. These maps are constructed using a parameterization of induction: estimates of Earth surface impedance, obtained at discrete geographic sites from magnetotelluric survey data, are convolved with latitude-dependent statistical maps of extreme-value geomagnetic activity, obtained from decades of magnetic observatory data. Geoelectric amplitudes are estimated for geomagnetic waveforms having 240 s sinusoidal period and amplitudes over 10 min that exceed a once-per-century threshold. As a result of the combination of geographic differences in geomagnetic activity and Earth surface impedance, once-per-century geoelectric amplitudes span more than 2 orders of magnitude and are an intricate function of location. For north-south induction, once-per-century geoelectric amplitudes across large parts of the United States have a median value of 0.26 V/km; for east-west geomagnetic variation the median value is 0.23 V/km. At some locations, once-per-century geoelectric amplitudes exceed 3 V/km.

Publication Year 2016
Title Geoelectric hazard maps for the continental United States
DOI 10.1002/2016GL070469
Authors Jeffrey J. Love, Antti Pulkkinen, Paul A. Bedrosian, Seth Jonas, Anna Kelbert, Erin (Josh) Rigler, Carol Finn, Christopher Balch, Robert Rutledge, Richard Waggel, Andrew Sabata, Janet Kozyra, Carrie Black
Publication Type Article
Publication Subtype Journal Article
Series Title Geophysical Research Letters
Index ID 70182813
Record Source USGS Publications Warehouse
USGS Organization Geologic Hazards Science Center