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P-wave and S-wave tomographic models for the Northeast Africa region. They have been calculated using relative travel time tomography. For full details of method and models see the following papers: Civiero, C., Hammond, J. O. S., Goes, S., Fishwick, S., Ahmed, A., Ayele, A., Doubre, C., Goitom, B., Keir, D., Kendall, M., Leroy, S., Ogubzghi, G., Rumpker, G., Stuart, G. W. Multiple mantle upwellings beneath the Northern East-African rift system from relative P-wave traveltime tomography, Geochem. Geophys. Geosyst., doi:10.1002/2015GC005948 (2015) Civiero, C., Goes, S., Hammond, J. O. S., Fishwick, S., Ahmed, A., Ayele, A., Doubre, C., Goitom, B., Keir, D., Kendall, M., Leroy, S., Ogubzghi, G., Rumpker, G., Stuart, G. W. Small-scale thermal upwellings under the Northern East African rift from S-wave travel-time tomography, J. Geophs. Res. Doi:10.1002/2016JB013070 (2016). The geographical extent of the models is Latitude: 24.7S - 27.0N, Longitude: 25.4E - 57.2E, Depth: 0 - 900 km. See see hitcount files and papers for areas of reasonable resolution.
The dataset contains condensed results of seismic refraction survey, that can be regarded as “hard data”. Data files Syczyn-1_P.ASC and Syczyn-1_S.ASC represents tables obtained for line Syczyn-1, wave P and wave S respectively; Data files Syczyn-2_P.ASC and Syczyn-2_S.ASC represents tables obtained for line Syczyn-1, wave P and wave S respectively. Each file contains 4 columns: Record No. – sequential record identifier; Source location – distance from the beginning of the line to the (current) source point (in meters); Receiver location – distance from the beginning of the line to the given receiver (in meters); First Break – delay time between emission of the wave to its arrival at the given receiver point (seconds). Dataset is formatted in simple table, that can be imported to other seismic software for modelling velocity field. Different computing algorithms generate slightly different velocity models, so it can be useful to have hard data for comparison.
Published results on the Hydrate Bearing Effective Sediment (HBES) rock physics model (NERC Grant NE/J020753/1)
This excel spreadsheet contains P-wave and S-wave velocity and attenuation data calculated with a novel rock physics model for hydrate bearing sediments. The model has been published in: Marín-Moreno, H., S. K. Sahoo, and A. I. Best (2017), Theoretical modeling insights into elastic wave attenuation mechanisms in marine sediments with pore-filling methane hydrate, Journal of Geophysical Research: Solid Earth, 122(3), 1835-1847, doi:10.1002/2016JB013577.
Dataset contains 3D synthetic seismic waveforms for axisymmetric global Earth velocity models. The waveforms were calculated using the finite difference approach with the PSVAxi algorithm (Jahnke, G et al., 2008. doi:10.1111/j.1365-246X.2008.03744.x). The Earthmodels are 1D and use PREM parameters except close to the core-mantle boundary (CMB) where 3D ultra-low velocity zones (ULVZs) are added to the PREM background model. ULVZ are thin layers of strongly reduced seismic velocities located at the CMB that have been observed in several regions of the Earth. The dataset models interaction of the seismic wavefield with ULVZ structure with varying elastic parameters (P-wave, S-wave velocity, density), location (location at source or receiver side along the great circle path), ULVZ length, shape (box, Gaussian, trapezoid) and height. Detailed description of the approach and the model space are given in Vanacore et al, (2016). Data format is SAC (Seismic Analysis Code). Vanacore, E.A., Rost, S., Thorne, M.S., 2016. Ultralow-velocity zone geometries resolved by multidimensional waveform modelling. Geophys. J. Int. 206, 659–674. doi:10.1093/gji/ggw114