CURIE: A continental-scale probabilistic magnetotelluric reference model of USArray data for the contiguous United States

Summary Magnetotellurics (MT) provides critical constraints on Earth’s electrical conductivity structure and thereby illuminates lithosphere and mantle processes. The EarthScope USArray MT program provides a unique opportunity to investigate large-scale tectonic and compositional variations across the contiguous United States (U.S.). However, uniform MT interpretation is hindered by data quality and the computational and initialization demands of 3D inversion. To provide a physically consistent and uncertainty-aware continental-scale baseline, we develop CURIE (continental U.S. 1D resistivity inference ensemble), comprising two complementary probabilistic reference model ensembles obtained by independently inverting the Zxy and Zyx components from 1773 MT stations using unsupervised, physics-driven normalizing flows. For each station and mode, CURIE provides posterior resistivity distributions, uncertainty estimates, and predicted MT responses. We assess the 1D assumption using filtered data misfit, mode differences, and phase tensor skew and ellipticity. Most stations yield filtered misfits below 4, indicating that 1D models reproduce the dominant responses. Low phase-tensor skew and ellipticity broadly coincide with low-misfit regions across the Interior Plains and the Intermontane Plateaus, whereas elevated indicators and misfits along tectonic and continental margins identify areas where 1D interpretation requires greater caution. At shallow depths, CURIE recovers resistivity patterns associated with major geological provinces; at mid- to lower-lithospheric depths, it resolves the broad contrast between the tectonically active western U.S. and the stable eastern craton. Differences between the Zxy and Zyx results along the Pacific and Gulf coasts, and in Florida further reflect orthogonal sensitivities to conductivity gradients and indicate 3D structural orientations, with some near-coast misfits influenced by the coast effect. The resulting dataset provides a continent-wide probabilistic reference that offers a first-order view of the U.S. electrical structure while supporting data quality assessment, identification of potential 3D effects, and development of initial or reference models for future 3D inversion and geodynamic interpretation.