Comparison of the deep crustal structure and seismicity of North America with the Indian subcontinent

We summarize geophysical information from North America and India, and find many similarities in the deep crustal structure of the two continents. From this, we infer that similar processes have operated, particularly in the accretion and stabilization of the cratonic regions. Seismic images and other data suggest that plate tectonic processes have been active, both in the North American and Indian shields, since the late Archean. Precambrian orogens and high-pressure granulite terrains of both regions have developed nearly identically through time since about 2500 Ma. Such similarities invite direct comparisons of deep crustal structure. Here we present results from work in North America including: maps of crustal thickness, maps of average P-wave velocity of the crystalline crust, maps of average P-n (sub-Moho) velocity, and statistical analysis of crustal properties.