Seismic velocity grids, Eastern North American Margin Community Seismic Experiment (ENAM CSE)

These velocity models were constrained by traveltime tomography of active-source Ocean Bottom Seismometers data along three profiles from the Eastern North American Margin Community Seismic Experiment (ENAM CSE). P-wave velocity models for Line 1, Line 2, and Line 3 are included as well as a S-wave velocity model for Line 3. Collectively, these tomographic velocity images reveal subsurface properties and information on the ancient rifting event between eastern North America and west Africa during the breakup of Pangea and formation of the Central Atlantic ocean, but may also be relevant for other studies such as modern processes along the margin. The data files are in ASCII format and the velocity models are exported every 180 meters in the horizontal X direction, and every 90 meters in the vertical Z direction. Columns are: X-coordinate (km), Z-coordinate (km), Vp (km/s). The X-coordinate of Line 1 and Lines 2 models is zero at the coastline. Model Z-coordinates are positive and increasing with depth. Line 1 and Line 2 models start at one kilometer above sea level (-1.0) due to the landward extension of the profiles; however, the onshore domain is not shown or archived here due to poor ray coverage. For the line 3 velocity model, the data file columns are: X-coordinate (km), Z-coordinate (km), Vs (km/s). This velocity model was produced by traveltime inversion of shear-waves that were converted at the seafloor. Note that these phases traveled as P-waves throughout the water column, hence there is a corresponding P-wave velocity of ~1.5 km/s above the seafloor. This data set was generated as part of the projects called Seismic study of mantle deformation and melt extraction during continental breakup in the ENAM primary site; and, Final stages of breakup and early spreading history of the Eastern North America passive margin from multichannel seismic data. Funding was providing through NSF awards OCE15-51717 and OCE15-51807.