Abstract
EMScope, a component of the NSF Earthscope project, is installing a 70 km-spaced grid of long-period magnetotelluric stations across the USA. Rapid data quality control and generation of derived data products provides an accessible resource openly available without charge or restriction through the IRIS Data Management Center and EMScope data portals via a set of data discovery tools. These data are available typically within two weeks of acquisition. Initial 3-d inversion of such EMScope data from the US Pacific Northwest shows substantial coherence between crust and mantle electrical conductivity variations, the boundaries of major physiographic provinces, and seismically delineated features.
