@article{fdi:010082665,
  title = {{M}itigating the ill-posedness of first-arrival traveltime tomography using slopes : application to the eastern {N}ankai {T}rough ({J}apan) {OBS} data set},
  author = {{S}ambolian, {S}. and {G}orszczyk, {A}. and {O}perto, {S}. and {R}ibodetti, {A}lessandra and {T}avakoli, {F}. {B}.},
  editor = {},
  language = {{ENG}},
  abstract = {{F}irst-arrival traveltime tomography is one of the most used velocity model building techniques especially in sparse wide-angle acquisitions for deep crustal seismic imaging cases. {R}elying on the inversion of a picked attribute, the absolute traveltimes, the approach is ill-posed in terms of non-uniqueness of the solution. {T}he latter is remedied by proper regularization or the introduction of prior information. {I}ndeed, since traveltime kernels are vulnerable to the velocity-depth ambiguity, the inversion is stabilized by the introduction of complementary data like reflections and explicit reflectors in the velocity models. {H}ere, we propose to supplement first-arrival traveltimes by their slopes, in other words the horizontal component of the slowness vectors at the sources and/or receivers. {S}lopes are a crucial attribute in state of the art scattering-based or reflection-based tomographic methods like slope tomography or wavefront tomography where the differential information is needed in order to locate the scattering events position or to parametrize the wavefront. {T}he optional but valuable injection of slopes as an objective measure in first-arrival traveltime tomography stabilizes the problem by constraining the emergence angle or in turn implicitly the turning point depth of the rays. {W}e explain why slopes have a tremendous added value in such a tomographic problem and highlight its remedial effect in cases where the medium is unevenly illuminated. {W}e also show that the contribution of slopes become even more significant when the acquisition is sparse as it is generally the case with ocean-bottom seismometer surveys. {T}he inferred models from such an extended time-attributes tomography will be used as initial guesses in a full-waveform inversion workflow context. {T}he proposed strategy is benchmarked in 2-{D} media against a dip section of the {SEG}/{EAGE} overthrust model and then followed by a revisit of ocean bottom seismometers data from the eastern-{N}ankai subduction margin as a real deep crustal case study.},
  keywords = {{I}nverse theory ; {W}aveform inversion ; {C}ontrolled source seismology ; {C}rustal {I}maging ; {S}eismic tomography ; {JAPON} ; {NANKAI} {FOSSE}},
  booktitle = {},
  journal = {{G}eophysical {J}ournal {I}nternational},
  volume = {227},
  numero = {2},
  pages = {898--921},
  ISSN = {0956-540{X}},
  year = {2021},
  DOI = {10.1093/gji/ggab262},
  URL = {https://www.documentation.ird.fr/hor/fdi:010082665},
}