Body Wave Speed Structure of Eastern North America

The eastern, passive margin of the North American continent is more heterogeneous than originally envisioned. Imaged by teleseismic body wave arrivals, both compressional Vp and shear Vsh, the lithospheric mantle of the stable, eastern North America contains rapid and large wave speed variations from the fast, older interior toward the slower, margin structures along the continental edge. At multiple regions at the continental edge, wave speeds indicate the presence of a small amount of melt,