Database of Central and Eastern North American Seismic Velocity Structure

The “Database of Central and Eastern North American Seismic Velocity Structure” involves the compilation of one-dimensional (1D) seismic velocity-depth functions for central and eastern North America (CENA). The present database is an update of the report by Chulick and Mooney (2002) who present a compilation and statistical analysis of 1D seismic velocity-depth functions for North America and its margins. All seismic velocity-depth functions are extracted from peer-reviewed journal articles, with 86% derived from active-source seismic refraction profiles and the remaining 14% from receiver functions or local earthquake tomography models. No reanalysis of the original seismic field data was undertaken. The database of Chulick and Mooney (2002) covered a much larger region than central and eastern North America. In 2013 the USGS focused on augmenting the Chulick and Mooney (2002) database to update the coverage specifically for central and eastern North America. This augmented compilation was done to help characterize the seismic site response at the locations of nuclear power facilities and was a deliverable specified by a USGS-Nuclear Regulatory Commission Inter-agency Work Agreement, which can be found at https://www.nrc.gov/docs/ML1428/ML14280A412.pdf. Each seismic velocity-depth function is specified by its unique latitude and longitude and consists of the published crustal model for the subsurface Earth layers at that location, with each layer specified by compressional-wave velocity, shear-wave velocity, thickness, and depth. Each entry also includes other information, such as: elevation, geologic province, age of last significant thermo-tectonic activity, and the principal seismic methodology used to determine the velocity-depth function. Chulick, G.S., and Mooney, W.D., 2002, Seismic Structure of the Crust and Uppermost Mantle of North America and Adjacent Oceanic Basins: A Synthesis, Bulletin of the Seismological Society of America, vol.92, no.6, p.2478–2492.