Whole-mantle radially anisotropic shear velocity structure from spectral-element waveform tomography
By S. French, Barbara Romanowicz. 2014
455 citations recorded by the source corpus.
S U M M A R Y The radially anisotropic shear velocity structure of the Earth’s mantle provides a critical window on the interior dynamics of the planet, with isotropic variations that are interpreted in terms of thermal and compositional heterogeneity and anisotropy in terms of flow. While significant progress has been made in the more than 30 yr since the advent of global seismic tomography, many open questions remain regarding the dual roles of temperature and composition in shaping mantle convection, as well as interactions between different dominant scales of convective phenomena. We believe that advanced seismic imaging techniques, such as waveform inversion using accurate numerical simulations of the seismic wavefield, represent a clear path forwards towards addressing these open questions through application to whole-mantle imaging. To this end, we employ a ‘hybrid’ waveform-inversion approach, which combines the accuracy and generality of the spectral finite element method (SEM) for forward modelling of the global wavefield, with non-linear asymptotic coupling theory for efficient inverse modelling. The resulting whole-mantle model (SEMUCB-WM1) builds on the earlier successful application of these techniques for global modelling at upper mantle and transition-zone depths (≤800 km) which delivered the models SEMum and SEMum2. Indeed, SEMUCB-WM1 is the first whole-mantle model derived from fully numerical SEM-based forward modelling. Here, we detail the technical aspects of the development of our wholemantle model, as well as provide a broad discussion of isotropic and radially anisotropic model structure. We also include an extensive discussion of model uncertainties, specifically focused on assessing our results at transition-zone and lower-mantle depths.
Subfields: Geophysics
View Paper: https://www.semanticscholar.org/paper/3a5a7d8c164e1dde468ff6ee1e421faf9732e824
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In Geophysics
Citations in the corpus
- Primary magmas and mantle temperatures through time (2017, result): “This means that some thermal anomalies could anchor in this transition zone (410–660 km), which is consistent with the literature on high resolution seismic tomography and geochemical studies [Courtillot et al., 2003; Husson and Conrad, 2012; Fukao and Obayashi, 2013; French and Romanowicz, 2014].”
- TX2019slab: A New P and S Tomography Model Incorporating Subducting Slabs (2019, background): “The locations of these fast anomalies generally agree with previous studies (e.g., Amaru, 2007; French & Romanowicz, 2014; Grand, 2002; Li et al., 2008; Moulik & Ekström, 2014; Obayashi et al., 2013; Ritsema et al., 2011).”
- Morphology of seismically slow lower-mantle structures (2016, background): “Sharp changes across LLSVP boundaries are also seen in seismic anisotropy (Wang & Wen 2007a; Cottaar & Romanowicz 2013; Lynner & Long 2014) and compressional wave speed (Frost & Rost 2014).”
- Global adjoint tomography: first-generation model (2016, unknown): “D spectral-element simulations of wave propagation in the mantle coupled with a normal-mode solution in a spherically symmetric core (Capdeville et al. 2003; Lekić & Romanowicz 2011; French et al. 2013; French & Romanowicz 2014).”
- Global adjoint tomography—model GLAD-M25 (2020, result): “The perturbations in GLAD-M25 tend to be larger than in the other models, consistent with observations by French & Romanowicz (2014, 2015), whose model is also based on a form of waveform inversion.”