Geoelectric hazard maps for the continental United States

Geophysical Research Letters
By: , and 

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Abstract

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.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Geoelectric hazard maps for the continental United States
Series title Geophysical Research Letters
DOI 10.1002/2016GL070469
Volume 43
Issue 18
Year Published 2016
Language English
Publisher Wiley
Contributing office(s) Geologic Hazards Science Center
Description 10 p.
First page 9415
Last page 9424