Crustal structure beneath the Florida-to-Edmonton broadband seismometer array

Ps receiver functions were stacked to determine crustal thickness and V_p/V_s ratios for the 28 stations of the Florida-to-Edmonton Broadband Seismometer Array and 6 adjacent permanent stations. Roots of thickened crust exist beneath the Paleozoic Appalachian orogen and the Proterozoic Trans-Hudson orogen. The ratios of surface elevation to root thickness are lower than observed in young, active orogens, as are average crustal root buoyancies determined from gravity data. These results are consistent with global trends, and may be explained by increased crustal root density due to metamorphism. Crustal thickening is also observed beneath the Mid-Continent Rift in Iowa, consistent with compressional inversion of the rift during the Grenville orogeny.