EARTHSCOPE-ENABLED INSIGHTS INTO THE NORTH AMERICAN CRUST AND MANTLE (Invited Presentation)

Recordings from USArray, the seismological component of EarthScope, have revealed the crust and mantle beneath North America at unprecedented resolution. A variety of body wave, surface wave, and receiver function studies have yielded images that have motivated the formulation of hypotheses that relate intraplate deformation and volcanic activity to newly-imaged crustal and lithospheric structures. In the west, these addressed the gap in seismicity along the Cascade subduction zone (e.g. Roth et al., 2008; Burdick et al., 2009), the magmatic system beneath the Yellowstone hotspot (e.g. Huang et al., 2015), and its connection with the deep mantle (Schmandt et al., 2012; Tian and Zhao, 2012). As the USArray moved into the eastern half of the United States where data had been even more sparse, new models illuminated connections between rift structure and deeper processes at the Midcontinent Rift (e.g. Burdick et al., 2014) and the Reelfoot Rift (Chen et al., 2014), and the origins of seismicity and volcanism in the southeastern US (e.g. Schmandt and Lin, 2014; Biryol et al., 2016).

In this presentation, we tackle the challenge of imaging structures from the crust down to the mid-mantle using standard and probabilistic analyses of complementary seismic datasets. We present crustal structure constraints from a joint interpretation of Ps and Sp receiver functions as well as from a probabilistic inversion of ambient noise measurements of Rayleigh and Love wave dispersion. We then investigate the relationship between seismicity, volcanism, and structural variations in the crust and mantle. We contextualize these comparisons using common conversion point stacks of Sp receiver functions and a new 3D tomographic mantle model derived using P wave traveltime data. We conclude by quantifying the improvement in seismic images attributable to new data from the EarthScope project.