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 Jeffrey J. Love 2016 <p><span>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&nbsp;s sinusoidal period and amplitudes over 10&nbsp;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&nbsp;V/km; for east-west geomagnetic variation the median value is 0.23&nbsp;V/km. At some locations, once-per-century geoelectric amplitudes exceed 3&nbsp;V/km.</span></p> application/pdf 10.1002/2016GL070469 en Wiley Geoelectric hazard maps for the continental United States article