In a subduction zone, the volcanic arc marks the location where magma, generated via flux melting in the mantle wedge, migrates through the crust and erupts. While the location of deep magma broadly defines the arc position, here we argue that crustal structures, identified in geophysical data from the Washington...
Ground level electric fields arising from geomagnetic disturbances (GMDs) are used by the electric power industry to calculate geomagnetically induced currents (GICs) in the power grid. Current industry practice is limited to electric fields associated with 1‐D ground electrical conductivity structure, yet at any given depth in the crust and...
Long period (10–20,000 s) magnetotelluric (MT) data are being acquired across the continental USA on a quasi-regular grid of ∼70 km spacing as an electromagnetic component of the National Science Foundation EarthScope/USArray Program. These data are sensitive to fluids, melts, and other organic indicators, and thus provide a valuable complement...
Eleven years (1932-1942) of electric potential and magnetic measurement at the Tucson observatory
represent a unique very long period magnetotelluric (MT) data set. We report here on a careful reanalysis of this
data using modern processing techniques. We have developed and used novel methods for separating out the
quasi-periodic daily...