Toomey, Douglas, et al., (2017), ETOMO: Shallow mantle seismic velocity data at the Endeavour segment of the Juan de Fuca Ridge (investigators Doug Toomey, Brandon VanderBeek, Emilie Hooft, William Wilcock). Interdisciplinary Earth Data Alliance (IEDA). doi:10.1594/IEDA/324049
This data set is a tomographic model of P-wave seismic velocity structure at a shallow mantle depth of 7.8 km beneath the seafloor at the Juan de Fuca Endeavour Ridge. The model was derived from active-source data acquired during the ETOMO 3-D seismic tomography experiment conducted during Langseth cruise MGL0910 in 2009 (chief scientists Doug Toomey, Emilie Hooft, William Wilcock). The model and results are described in VanderBeek et al. (2016). Using a 3-D starting model of crustal velocity and thickness from previous tomographic studies of crustal refractions and Moho reflections, an iterative tomographic inversion was performed with more than 5,000 hand-picked Pn mantle refraction arrival times. Travel-time residuals were inverted for 3-D slowness perturbations, and ray paths and travel-times were predicted using a shortest-path algorithm. Ray tracing was performed on a 3-D grid parameterized with anisotropic slowness and seafloor topography. Azimuthal variations in Pn travel-time residuals were used to identify segment-scale anisotropic structure. The data set is in ASCII format and contains longitude, latitude and velocity. It was generated as part of the projects called ETOMO: Endeavour Seismic Tomography Experiment and Testing Models of Magmatic and Hydrothermal Segmentation: A 3-D Seismic Tomography Experiment at the Endeavour Ridge. Funding was provided by NSF Ridge 2000 program grants OCE04-54747 and OCE04-54700.