NACr14: A 3D model for the crustal structure of the North American Continent

Based on the large number of crustal seismic experiments carried out in the last decadeswe create NACr14, a 3D
crustal model of the North American continent at a resolution of 1° × 1°. We present maps of thickness and average
velocities of the main layers that comprise the North American crystalline crust, obtained from the most
recent seismic crustalmodelswithin the USGS crustal structure database. However, the crustal data are unevenly
distributed and in some cases discrepancies exist between published models. In order to construct a consistent
3D crustal model with three layers in the crystalline crust, we refrained from a direct interpolation of the crustal
seismic parameters in the database. Instead, weimplemented the following sequence of steps: 1. Definition of the
geometry of the main tectonic provinces of North America; 2. Selection and evaluation of the reliability of seismic
crustal models in the database; 3. Estimation of the P-wave seismic velocity and thickness of the upper, middle
and lower crust for each tectonic province; 4. Estimation of the interpolated Pn velocity distribution. The resulting
average velocity of the crystalline crust ismostly consistent with that of the seismic points. The main variations of
the structure of the crystalline crust of North America displayed in the model can be related to its tectonic evolution.
The model, available in a digital form, can be used in various geophysical applications, such as the correction
for the crustal effects in gravity and seismic tomography and models of dynamic topography, in order to
detect heterogeneities characterizing the underlying upper mantle