Orals: Thu, 7 May, 08:30–10:15 | Room -2.21
Teleseismic shear-wave splitting is a widely-used technique for measuring oriented fabric in the crust and upper mantle; such fabric is an important marker for current or past deformation. The technique yields both the orientation (fast direction) and cumulative intensity (split time) of the net fabric. However, published splitting results, particularly split times, can have puzzling inconsistencies that make mapping splitting over large areas challenging; semivariograms of compiled splitting results show a lack of spatial coherence in split time measurement when studies using different methods are combined. I present modelling work that demonstrates that these inconsistencies result from an inherent bias in splitting measurement, particularly pronounced for split time, that is sensitive to details of the data processing methods and is amplified by averaging single-event measurements. With a correct choice of averaging method (error-surface stacking), this bias can be mitigated sufficiently to allow split time to be mapped over large areas, as demonstrated using compiled data from western Canada. The results show strong spatially-coherent variations along the strike of the Cordillera, which may represent regions of dominant vertical vs. horizontal flow in the upper mantle, driven by complex Cordilleran active tectonics.
How to cite: Frederiksen, A., Phillips, C., and Gu, Y.: Mapping upper-mantle fabric at continental scale: frozen tectonics and active flow patterns in western Canada, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-4099, https://doi.org/10.5194/egusphere-egu26-4099, 2026.
The enigmatic radial anisotropy of the upper mantle remains difficult to resolve. Recent global models show strong disagreements and suggest different inferences on mantle dynamics and evolution. Here, we present a new radially and azimuthally anisotropic shear-wave velocity model of the upper mantle, LLCS-2026, and validate its key patterns using independent seismic and thermodynamic phase-velocity inversions for tectonic-type-average 1D profiles. LLCS-2026 is computed using waveform fits of 1,630,432 seismograms (1,252,717 vertical; 377,715 transverse components). Automated multimode waveform inversion is used to extract structural information from surface and S waveforms in very broad period ranges, from 11 to 450 s, with most data sampling in the 20–350 s period range. The vertical and transverse component waveforms are jointly inverted for the isotropic average shear-wave velocities, their pi-periodic and pi/2-periodic azimuthal anisotropy, and radial anisotropy. Statistical and manual outlier analysis yields a final dataset of 1,009,038 seismograms (765,302 vertical, 243,736 transverse components) that constrains the final model, which captures complex patterns of seismic isotropic and anisotropic structure within the Earth. In agreement with previously published models, prominent low-velocity anomalies indicative of thin lithosphere and partial melting are observed at 20-150 km depth beneath mid-ocean ridges. At 300-400 km, however, high isotropic-average velocities are present in the vicinity of some of the ridges in the Indian and Atlantic oceans. They suggest drips of cold, lithospheric mantle material, probably related to rapid lithospheric cooling in the complex 3D context of triple junctions and ridge-hotspot systems. Radial anisotropy is positive (Vsh > Vsv) at 100-150 km depth everywhere in the mantle, with cratons showing smaller anisotropy compared to other units. Below 200-250 km depth, radial anisotropy is negative (Vsv > Vsh) nearly everywhere. The depth at which the anisotropy sign changes varies with tectonic region. The anisotropy sign flips at the shallowest depth (~200 km) beneath young oceans and continents and at the greatest depth (~250 km, on average) beneath cratons. Radial anisotropy is also negative in the top 50 km of the oceanic lithosphere. Together with azimuthal anisotropy observations, this indicates a complex pattern of crystallographic preferred orientations created by mantle flow beneath mid-ocean ridges, with an interplay between the alignment of crystals due to the vertical flow below the ridge and the lateral flow away from it. Independent seismic (Civiero et al. 2024) and thermodynamic (Lebedev et al. 2024; Xu et al. 2025) inversions of phase-velocity data confirm and validate the anisotropy-sign-flip observations and inferences.
References
Civiero, C., Lebedev, S., Xu, Y., Bonadio, R. and Lavoué, F., 2024. Toward tectonic‐type and global 1D seismic models of the upper mantle constrained by broadband surface waves. Bulletin of the Seismological Society of America, 114, 1321-1346.
Lebedev, S., Fullea, J., Xu, Y. and Bonadio, R., 2024. Seismic thermography. Bulletin of the Seismological Society of America, 114, 1227-1242.
Xu, Y., Lebedev, S. and Fullea, J., 2025. Average physical structure of cratonic lithosphere, from thermodynamic inversion of global surface-wave data. Mineralogy and Petrology, 1-12.
How to cite: Lebedev, S., Lavoué, F., Celli, N. L., and Schaeffer, A. J.: Radial anisotropy of the upper mantle, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-5995, https://doi.org/10.5194/egusphere-egu26-5995, 2026.
The central Mediterranean area is a place where seismic anisotropy measurements have been collected for years, mainly along the Italian peninsula. Several different techniques have been applied to obtain this information, that carries relevant indications on the state of deformation at depth, both in the Earth’s crust and in the mantle. The most common type of measurements comes from the analysis of shear wave splitting of core phases (*KS), and from splitting intensity measurements. Seismic anisotropy patterns are a major support in answering questions such as where tectonic plates are actively deforming and which processes drive plate deformation. These are some of the questions addressed by the AdriaArray project. The seismic experiment AdriaArray aimed to densify the collection of seismographic data to the east with respect to the Adriatic microplate. The area covered by the project spans from southern France to the Black Sea in longitude and from Central Europe to the central Mediterranean in latitude, reaching the Sicily channel and the Hellenic Trench. Part of this wide area is already well studied for seismic anisotropy, as previously obtained data show. However, AdriaArray acquired data from 950 permanent and temporary broad-band stations thanks to the cooperation of nearly 40 institutions (https://orfeus.readthedocs.io/en/latest/adria_array_main.html) and most of them, located in the eastern part of AdriaArray study region, are now under analysis. Within the project, a Collaborative Research Group dedicated to seismic anisotropy has been created. It is working on building a dataset of shear-wave splitting measurements by improving already produced results with new data. The same has been done with splitting intensity measurements, with ongoing analyses for regions such as Sardinia, the eastern Adriatic coast and further east.
How to cite: Pondrelli, S., Rewers, J., Środa, P., Zailac, K., Stipčević, J., and Salimbeni, S.: Seismic anisotropy measurements within AdriaArray: a review of previous and new data, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-3092, https://doi.org/10.5194/egusphere-egu26-3092, 2026.
The Western Hellenic Subduction Zone is characterized by a transition from oceanic to continental subduction. The change occurs at the Kephalonian transform fault. However, how this transition takes place at depth remains a topic of discussion. This setting thus provides us with an ideal natural laboratory to investigate how differences in subduction regimes affect the structure and dynamics of the system.
To this end, we compute receiver functions across two seismic arrays from the MEDUSA broadband network, one imaging the oceanic subduction and the other imaging the continental subduction. We computed teleseismic receiver functions and performed harmonic decomposition along both lines. We then inverted these results to image the overriding crust, mantle wedge and slab, in terms of their velocity and anisotropic properties. By comparing the seismic properties of the continental and oceanic slabs, we aim to identify key differences in slab structure, seismic anisotropy, dehydration, and metamorphism between the two subduction regimes.
Preliminary results confirm a dipping low velocity zone in both regimes, corresponding to the slab's crust. Its signal is lost below 60 km in the isotropic component but remains visible to greater depths in the anisotropic component. Furthermore, we identify a low velocity layer within the mantle wedge which could resemble the altered LAB of the overriding plate. What sets the two domains apart is the cutoff depth of the isotropic component of the slab – it can be traced 10 km deeper in the South than in the North – and a generally lower anisotropy in the southern mantle wedge.
Until now the LAB has rarely been observed through conventional receiver function analysis or tomography in subduction zones. We therefore suggest that anisotropic inversion may provide unique insight into the structure of the mantle wedge and the subducting slab.
How to cite: Ziegler, J., Rondenay, S., and Piana Agostinetti, N.: Seismic Anisotropy in the Subducting Slab and Mantle Wedge of the Western Hellenic Subduction Zone from Receiver Functions, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-10259, https://doi.org/10.5194/egusphere-egu26-10259, 2026.
Shear wave splitting is widely used to probe seismic anisotropy, but its depth resolution is limited. Building on the formulation of Silver and Savage (1994), we apply a Bayesian inversion that explicitly accounts for uncertainty in shear-wave polarization orientation (θ) to resolve multilayer anisotropy from splitting parameters. We apply this approach to source-side S and SKS data from the Cocos subduction zone, and to SKS data from station NNA above the South America subduction zone and station SNZO at the southern Hikurangi margin. Subduction in all three regions is shallow to flat, minimizing dip-angle effects on SKS. The inversion yields tightly constrained fast directions for both upper and lower anisotropic layers. Three-layer inversions show progressive rotation with depth consistent with two-layer solutions, but are not required by the data. In the Cocos system, the upper-layer fast direction is unambiguously aligned with Cocos plate motion in the NNR reference frame, consistent with subduction-entrained flow. In contrast, beneath NNA and SNZO, the upper and lower layers exhibit trench-subparallel and trench-normal anisotropy, respectively—opposite in layering sense to the poloidal–toroidal flow structure predicted by dynamic models. If both layers reside in the subslab mantle, the trench-parallel upper layer flow would decouple the deeper mantle from the slab, raising questions about how the apparent subduction-driven flow is maintained at depth. Alternatively, the upper layer may reflect deformation within or above the slab. Possible sources of trench-parallel anisotropy include frozen-in oceanic lithospheric fabrics, trench-parallel mantle-wedge flow, or inherited fabrics related to nearby continental shear zones. These results highlight the complexity of subslab dynamics and demonstrate the value of probabilistic multilayer inversion for interpreting shear-wave splitting.
How to cite: Kuo, B.-Y., Peng, C.-C., and Montagner, J.-P.: Subslab flow beneath subduction zones revealed by multiple-layer shear wave splitting inversion, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-4243, https://doi.org/10.5194/egusphere-egu26-4243, 2026.
Fractures are ubiquitous throughout the Earth’s upper crust, spanning scales from microscopic cracks to large fault systems. Their hydromechanical behavior plays a critical role in controlling fluid migration in hydrocarbon, geothermal, and groundwater reservoirs, which, in turn, makes fracture detection, characterization, and monitoring an important objective in geoscience and engineering applications. Seismic methods, as indirect and non-invasive tools, have become central to this effort due to their ability to probe fractured media with adequate resolution and depth penetration. This work synthesizes our recent experimental and theoretical advances in the study of seismic characterization of fractured rocks, driven by several key observations. First, most fractured reservoirs exhibit effective seismic anisotropy because fractures often develop preferentially aligned with the local principal stress directions, leading to direction-dependent wave propagation. This anisotropy can be estimated using techniques such as shear-wave splitting, azimuthal velocity variations, and amplitude variations with offset and azimuth. Furthermore, we show that incorporating both fracture-induced and intrinsic background anisotropy, a rather common scenario in fractured environments, into inversion workflows is essential for a robust interpretation. Second, when a seismic wave propagates through a fluid-saturated fractured reservoir, it will be significantly attenuated and dispersed as a result of multiple intrinsic (e.g., inelastic effects due to solid and/or fluid friction effects) and extrinsic (e.g., geometrical spreading) mechanisms. In particular, when a seismic wave propagates through a fluid-saturated porous rock containing fractures, it produces fluid pressure gradients between the more compliant fractures and the stiffer embedding rock as well as between hydraulically connected fractures with different orientations and/or properties. Consequently, fluid flows until the pressure equilibrates, a phenomenon commonly referred to as wave-induced fluid flow (WIFF). This mechanism can alter the effective compliance of the fractures. Such compliance changes can significantly influence velocity and attenuation anisotropy across the seismic frequency range. The dependence of this type of mechanism on the petrophysical properties, fracture-geometry, and distribution makes the analysis of frequency-dependent seismic attributes particularly informative with regard to the hydromechanical properties. [NB2] Third, seismic responses in fractured media are highly sensitive to changes in their stress state, fluid saturation, and geometrical properties, thus, facilitating corresponding monitoring efforts through time-lapse seismic surveys. Finally, highly permeable fractures can often be directly imaged since open fractures with partial surface contacts generally have large mechanical compliance, which, in turn, produces strong scattering of seismic waves. Indeed, there is evidence from full-waveform sonic log data to suggest that the fracture mechanical compliance obtained from P-wave velocity changes and transmission losses correlates with the degree to which fractures are hydraulically open.
How to cite: Barbosa, N., Rubino, G., Caspari, E., and Holliger, K.: A review of the sensitivity of seismic wave velocity and attenuation to fracturing, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-11156, https://doi.org/10.5194/egusphere-egu26-11156, 2026.
Azimuthal seismic anisotropy in the upper mantle is crucial for understanding the spatial patterns of past and present upper mantle deformation. Traditional interpretation of such anisotropy attributes to relative shear between surface plates and mantle. This requires the orientation of anisotropy azimuths to remain constant with depth. However, inferences of azimuthal anisotropy based on surface wave tomographic models often reveals depth-dependent azimuths. To this end, the existence of mechanically weak, thin asthenosphere beneath the lithosphere facilitates the channelization of plate-driven Couette flow and pressure-driven Poiseuille flow. The combination of two flows, especially when misaligned, yields depth rotations of asthenospheric shear. This provides a geodynamically plausible link between asthenospheric flow properties and depth rotations of azimuthal seismic anisotropy. In this submission, we utilize publicly available azimuthal seismic anisotropy models together with predictions from a global mantle flow model that incorporates Couette/Poiseuille flow. We find that Poiseuille flow profoundly affects depth rotations of seismically inferred azimuthal anisotropy. Prominent depth rotations are under the Atlantic basin and the Nazca plate, where Poiseuille flow dominates the modeled asthenospheric flow regime. Significant Poiseuille flow may exist beneath the Indian basin, yet with small depth rotation, probably because of its directional alignment with Couette flow. Our results indicate that interpretation of azimuthal seismic anisotropy cannot be simply tied to relative shearing between plates and mantle. Instead, the relative importance of Couette and Poiseuille flows must be taken into account.
How to cite: Wang, Z. R., Conrad, C. P., Lebedev, S., Iaffaldano, G., and Hopper, J. R.: Depth rotations of azimuthal seismic anisotropy associated with relative importance of Couette/Poiseuille flow in the asthenosphere, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-2307, https://doi.org/10.5194/egusphere-egu26-2307, 2026.
We investigate the seismic anisotropy of the Rotondo granite (Gotthard Massif, Swiss Alps) by integrating geological and geophysical data from lab to field scale. We compare our modeled anisotropic properties with decameter measurements from boreholes and kilometer-scale regional seismicity data from the Bedretto Underground Laboratory for Geosciences and Geoenergies, demonstrating clear links between deformation fabrics and observed seismic anisotropy across scales.
Using field- and micro-scale analyses of deformation styles and fabric orientations, we delineate discrete structural domains characterized by varying strain intensities and fabric types, ranging from isotropic granite to fractured zones or proto-mylonitic shear zones. Proto-mylonitic zones exhibit strong phyllosilicate SPO and higher percentage of Vp anisotropy (~8-27%, range is dependent on compositional variations). Fractured zones vary in frequency within the Rotondo massif and also exhibit elevated Vp anisotropy (>7.5%). For each structural domain, we compute effective elastic stiffness tensors (or 'rock recipes') to characterize their intrinsic seismic velocities. We introduce a new approach for combining multiple lithological “rock recipes” that emphasizes collective impact on bulk anisotropy and spatial context, rather than volume-weighted averaging.
We observe a scale-dependent shift in anisotropic influence, where the control of ductile fabrics (<20 m) is progressively superseded by fractures as the observational scale increases. When these heterogeneous fabrics are aggregated, destructive interference among strongly anisotropic components reduces the bulk anisotropy to ~2.5%, which is below laboratory measured values. We find good agreement between our theoretical results and cross-borehole effective Vp measurements within the Bedretto Lab. We also find qualitative evidence for anisotropy between event relocation models (e.g. Double Difference or NonLinLoc) of background seismicity in the region at the 1-5 kilometer scale. These results demonstrate consistency in seismic anisotropy estimation across methods and scales, and show the utility of geologically-based anisotropy characterization.
How to cite: Hinshaw, E., Ceccato, A., Zappone, A., Behr, W., and Obermann, A.: Multi-scale Seismic Anisotropy of the Rotondo Granite: Linking Deformation Fabrics to Wave Propagation, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-9651, https://doi.org/10.5194/egusphere-egu26-9651, 2026.
Posters on site: Fri, 8 May, 10:45–12:30 | Hall X2
The slowness surfaces for P, S1 and S2 waves in anisotropic medium are defined by solving the Christoffel equation. The regular point on the slowness surface can be mapped on corresponding group velocity surface. The irregular (singularity) point on the slowness surface results in the plane curve in the group velocity domain (Stovas et al., 2024).
The characteristic equations for double and triple singularity points define the tangent cone of second and third order, respectively. If the plane wave passes through singularity points in some layers of multilayered model, the effective characteristic equation has order given by product of orders of characteristic equations from individual layers. Therefore, the order of effective characteristic equation can be computed as N=2K3L, where K and L are the number of layers with double and triple singularity points, respectively. The effective characteristic polynomial FN(Δp1,Δp2,Δp3) (the N-th order tangential cone) for multi-layered model can be computed by resultant of individual characteristic polynomials,where Δpj,j=1,2,3, are the increments in slowness projections.The number of individual branches is given by J=Floor[(N+1)/2]. The dual curve ΦM (V1,V2,V3)=0 is the group velocity umage of Nth-order singularity point, where M=N(N-1)-2n-3c (Quine, 1982), with n and c being respectively the number of nodes and cusps for curve FN=0. It is shown that the tangential cone does not have cusps (c=0) but can have nodes if N≥6. The inflection points and bitangents for curve FN=0 respectively result in cusps and nodes for dual curve ΦM=0. The cusps affect the Gaussian curvature computed in vicinity of singularity point (Stovas et al., 2025). The irregularities in phase and group domain are illustrated in Figure by dots for two-layer model with double singularity points in both layers (N=4, J=2, n=2 and M=8).
Figure. Two-layer model with double singularity points. a) Curve F4=0 in affine plane (phase domain). Four inflection points on converted wave branch are shown by black dots. Two bitangents are shown by dotted lines limited by gray dots. b) Group velocity image (Φ8=0) of quartic singularity point (dual curve). Four cusps are shown by black dots, and two nodes are shown by gray dots. Solid and dashed lines stand for pure wave modes (S1S1 and S2S2) and converted (S1S2 and S2S1) waves, respectively.
References
Stovas, A., Roganov, Yu., and V. Roganov, 2024, Singularity points and their degeneracies in anisotropic media, Geophysical Journal International 238 (2), 881- 901.
Stovas, A., Roganov, Yu., and V. Roganov, 2025, Gaussian curvature of the slowness surface in vicinity of singularity point in anisotropic media, Geophysical Journal International 240 (3), 1917-1934.
Quine, J.R., 1982, A Plücker equation for curves in real projective space, Proceedings of the American Mathematical Society, 85, no.1, 103-107.
How to cite: Stovas, A.: Singularity points in multi-layered anisotropic medium , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-3503, https://doi.org/10.5194/egusphere-egu26-3503, 2026.
The recent increase in seismic activity in the southern Sichuan Basin has attracted substantial public interest and simultaneously provides an important opportunity to investigate upper crustal anisotropy, which offers key constraints on the regional stress field and crustal deformation. In this study, we obtained 1,845 high-quality local shear-wave splitting measurements from 15 stations, along with 2,027 null measurements from 19 stations. The results reveal a single anisotropic layer characterized by a horizontal symmetry axis at depths of approximately 3–7 km. The fast polarization directions exhibit clear spatial variability, which is primarily controlled by the spatial distribution of earthquakes rather than temporal evolution. Near the Baimazhen Syncline, the fast polarization directions align with the strike of the strata and form a circular pattern around the synclinal core, indicating that the anisotropy in this region is dominantly structure-controlled. In contrast, stations located in the southern Weiyuan Anticline and the western Baimazhen Syncline display fast directions of N171.7°E and N45.9°E, respectively. These orientations are consistent with the P axes derived from earthquake focal mechanisms, suggesting that anisotropy in these areas is primarily governed by the regional stress field. Overall, this study enhances our understanding of the complex geological framework of the southern Sichuan Basin and underscores the need for caution when interpreting potential temporal variations in seismic anisotropy in future investigations. This work was supported by the National Natural Science Foundation of China (Grant 42374124).
How to cite: Qiang, Z., Wu, Q., and Li, Y.: Spatial Heterogeneity of Upper Crustal Anisotropy in the Southern Sichuan Basin (China) Revealed by Local Shear-Wave Splitting, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-4419, https://doi.org/10.5194/egusphere-egu26-4419, 2026.
The Alps, together with the Northern Apennines and the Northern Dinarides, represent one of the most complex and best-studied examples of continental collision in the world. Over the years, several active and passive seismic experiments have been deployed in the Alpine region. More recently, the installation of large and dense seismic arrays, such as AlpArray and AdriaArray, has provided unprecedented spatial coverage, enabling the development of increasingly detailed seismic velocity models. However, most existing regional models of the Alps primarily rely on isotropic seismic velocities. Radially anisotropic models, which map the parameter ξ = Vsh²/Vsv², provide complementary information by revealing the preferential orientation of anisotropic minerals and structural fabrics produced by past and ongoing tectonic processes.
In this study, we combine ambient noise and earthquake surface-wave data from more than 3,300 permanent and temporary broadband seismic stations to construct a high-resolution Alpine Radial Anisotropy model (AlpRA25) of the crust and upper mantle. Ambient noise data collected between 2017 and 2019 from approximately 700 seismic stations were used to calculate ~46,000 Rayleigh- and ~40,000 Love-wave dispersion curves. These were merged with ~295,000 Rayleigh- and ~200,000 Love-wave dispersion curves obtained from about 6,000 earthquakes recorded at approximately 3,300 broadband seismic stations between 1990 and 2022, resulting in a total of ~295,000 Rayleigh and ~240,000 Love dispersion curves spanning periods from 3 to 250 s.
These data were inverted for phase-velocity maps using a least-squares algorithm with an average knot spacing of 30 km. An a posteriori outlier analysis discarded 15% of the interstation measurements with the highest residuals, after which the model was recomputed. Local dispersion curves were then extracted at each grid node and evaluated for their frequency-dependent roughness. The Rayleigh and Love local dispersion curves were jointly inverted for 1-D shear-wave velocity structure using a particle swarm optimization algorithm, yielding vertical and horizontal shear-wave velocities (Vsv and Vsh, respectively). The final AlpRA25 model is a high-resolution 3-D model of Vsv, Vsh, and ξ from 5 to 250 km depth, covering the Alps, the Northern Apennines, the Northern Dinarides, and the adjacent foreland and back-arc basins. AlpRA25 provides new constraints on the lithospheric architecture and deformation of the Alpine region, highlighting the role of radial anisotropy in imaging tectonic processes from the crust to the upper mantle.
How to cite: Meier, T., Berger Roisenberg, H., Eckel, F., El-Sharkawy, A., Rosenberg, C., Boschi, L., and Cammarano, F.: AlpRA25: a new radial anisotropy model of the Alps from ambient noise and earthquake surface waves, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-7464, https://doi.org/10.5194/egusphere-egu26-7464, 2026.
The Haiyuan Fault, a major strike-slip structure in the northeastern Tibetan Plateau margin, is bounded by the first-order Tibetan Plateau and South China blocks, plus the second-order Ordos and Alxa blocks. Seismic anisotropy serves as a robust proxy for probing deep crustal deformation, geodynamic processes, and subsurface seismic structures. We conducted receiver function analyses on teleseismic data from two dense profiles and five broadband stations across the study area; crustal thickness (42–56 km) and Vp/Vs ratios (1.60–1.88) were quantified by the H-κ domain search algorithm, while common conversion point (CCP) imaging delineated the Moho discontinuity across the Haiyuan Arc Fault Zone. Crustal thickening reflects shortening driven by Tibetan-Eurasian collision, with the Haiyuan tectonic evolution linked to high-temperature/pressure regimes induced by Indo-Asian convergence. CCP images reveal a distinct Moho offset and ambiguous continuity beneath the fault zone, confirming it as a Moho-penetrating transcrustal structure associated with intense crustal extrusion from the plateau interior. We characterized multi-scale crustal anisotropy via shear-wave splitting (SWS) analysis of local earthquake data. SWS parameters exhibit clear zoning controlled by the Haiyuan Fault: fast polarization orientations are NNE–NE north of the fault and WNW–EW south of it. Within ~10 km of the fault, fast orientations align with the fault strike (WNW), indicating the fault’s stress influence range spans dozens of kilometers. Enhanced normalized time-delays near the fault signal stronger anisotropy along this strike-slip belt. Upper crustal anisotropy likely arises from crack-induced fabric, whereas middle-lower crustal anisotropy reflects deformation-controlled fabric. Spatial anisotropy patterns imply the combined effects of stress, faulting, and local tectonics. Notably, SWS results suggest the Haiyuan Fault constitutes the actual crustal boundary of the northeastern Tibetan Plateau, ~200 km north of the previously reported plateau block boundary.
How to cite: Shi, Y. and Gao, Y.: Crustal Deformation of the Haiyuan Fault Zone Inferred from Dense Seismic Array Observations, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-8643, https://doi.org/10.5194/egusphere-egu26-8643, 2026.
The North China Craton (NCC) exhibits a marked east-west contrast in its present-day tectonic framework. The eastern region features a thinned lithosphere hosting extensional basins like the Zhangjiakou-Bohai seismic belt and the Shanxi Graben. This area experiences intense crustal deformation and frequent seismicity. Conversely, the western region possesses a thicker lithosphere, greater crustal stability, and weak seismic activity. The central orogenic belt acts as a transitional zone in crust-mantle structure, characterized by dramatic crustal thickness variations, evidence of lithospheric modification, remnants of ancient structures, and is key for studying crust-mantle coupling/decoupling.
Crustal anisotropy serves as a crucial indicator for revealing lithospheric deformation. Analysis of seismic wave velocity anisotropy quantitatively constrains crustal stress, assesses fault activity, and infers deep material flow. This provides essential constraints for seismic hazard assessment and tectonic dynamics research.
This study utilized local-earthquake data (M>1) from the National Fixed Seismic Network to investigate crustal anisotropy across the NCC using the SAM (Shear-wave splitting Analysis Method) method. The extensive dataset, covering multiple temporal windows of seismic activity, provides strong temporal continuity and spatial coverage for analyzing anisotropy characteristics. Results reveal complex fast-wave polarization directions (FPDs) across the study area. The average FPD (~73°) aligns well with the regional mean maximum horizontal compressive stress (SHmax) direction in the NCC. However, the FPDs also display distinct local features correlating with specific structures, indicating significant local variability in the regional stress field. This manifestation of localized crustal anisotropy characteristics is vital for understanding the region's geodynamic activity. The local stress field variations suggest a heterogeneous crustal stress distribution, likely influenced by multiple geological factors.
How to cite: Wang, Q., Gao, Y., and Liu, G.: Crustal Anisotropy Characteristics in the North China Craton, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-8791, https://doi.org/10.5194/egusphere-egu26-8791, 2026.
Seismic anisotropy can provide important constraints about deformation processes within the lithosphere and underlying asthenosphere, as well as mantle flow patterns in tectonically complex regions. This study presents observations of seismic anisotropy in the upper mantle beneath the Dinarides and adjacent regions based on teleseismic SKS phase recordings from the AdriaArray temporary deployment, complemented by selected stations from the Croatian permanent seismic network and other available stations in the region. The combined datasets provide improved spatial coverage and allow for a more continuous regional assessment of anisotropic structure beneath the Dinarides.
Seismic anisotropy is investigated using a splitting-intensity approach, applied to teleseismic SKS phases. The splitting intensity quantifies the relative amplitude of the transverse component with respect to the radial component and provides a more robust measure of anisotropic effects. From the azimuthal variation of splitting intensity, the splitting parameters, fast-axis orientation and delay time, can be estimated, enabling direct comparison with earlier shear-wave splitting studies.
The inferred anisotropic pattern beneath the southern Dinarides is regionally coherent with fast axes in the direction perpendicular to the strike of the mountain chain. The fast axes in the Internal Dinarides, on the other hand, are generally pointing in the direction parallel to the strike of the mountain chain, which is also supporting previously published results. New and previously unpublished measurements are presented for stations in the northern Dinarides and in the transitional zone between the Dinarides and the Pannonian Basin, providing improved spatial coverage across this geodynamically important boundary.
This study highlights the importance of dense seismic observations and complementary analysis approaches for resolving anisotropic structures in complex orogenic settings. The expanded dataset and inclusion of splitting intensity measurements provide new constraints on upper-mantle deformation beneath the Dinarides and contribute to a more comprehensive understanding of the coupling between lithospheric tectonics and mantle dynamics in the central Mediterranean region.
How to cite: Zailac, K., Pondrelli, S., Salimbeni, S., and Stipčević, J.: Seismic Anisotropy Beneath the Dinarides: Implications for Adria-Eurasia Convergence, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-10589, https://doi.org/10.5194/egusphere-egu26-10589, 2026.
Bridgmanite is the most abundant intrinsically-anisotropic constituent of the lower mantle. Its deformation, thus, potentially translates to large-scale anisotropy that would accumulate in high-stress regions, particularly the interaction between subducted materials and the surrounding mantle. While most of the lower mantle is generally considered well-mixed, recent observations suggest structures at mid-mantle depths (800 – 1500 km). Their origin, however, often remains enigmatic. Recent state-of-the-art deformation experiments in bridgmanite at lower-mantle temperatures and pressures reveal a depth-dependent behavior of anisotropy. Coupled with realistic geodynamic models of mantle convection, the large-scale imprint of the depth-dependent fabric reveals a purely deformation-driven seismic discontinuity between 1000 – 1400 km depth that matches observations. The discontinuity appears sharpest in actively deforming regions, and becomes negligible closer to neutral ones. In this work, we investigate its seismic detectability around a subduction zone using three-dimensional global waveform modeling via AxiSEM3D. Given its likely presence across a broad range of frequencies, we assess the suitability of SS precursors for detecting this feature. Enhanced using array seismological methods, results show the presence of SS precursors in the transverse component generated by the anisotropic discontinuity. In addition, a flattened slab geometry produces a shallower SS precursor due to the interface formed between an overlying isotropic slab and an underlying strongly anisotropic (VSH>VSV) layer. We examine the azimuthal dependence of precursor amplitudes and their frequency dependence, with particular emphasis on the microseismic frequency band (~0.05 – 0.25 Hz). In light of these recent findings, we discuss its implications on the nature and origin of mid-mantle discontinuities.
How to cite: Magali, J. K., Yuan, Y., and Thomas, C.: Seismic detectability of a deformation-induced anisotropic discontinuity in the Earth’s lower mantle around a subduction zone using synthetic global modeling of SS precursors, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-19103, https://doi.org/10.5194/egusphere-egu26-19103, 2026.
The southwest region of Western Australia is one of the oldest continental regions on Earth, hosting the Archean Yilgarn Craton, bounded by the Proterozoic Albany-Fraser and Pinjarra orogens. Here we calculate shear wave splitting of the PKS and SKS teleseismic phases using stations from Phases 1 and 2 of the WA Array (average station spacing 40 km), as well as other temporary and permanent networks in the study region. We find evidence for coherent seismic anisotropy, with the regional average delay time (1.24 ± 0.62 s) comparable to the global average, δt = 1 s. Although fast polarization orientations show variation, they are not aligned with current plate motion and the expected asthenospheric flow direction. In the South West Terrane, fast polarization orientations match the trend of ancient structural faults. By contrast, structural faults in the Youanmi Terrane and the Eastern Goldfields Superterrane are oriented at an angle compared to the E–W and NE–SW fast polarizations. Instead, the seismic anisotropy pattern shows a striking similarity to E–W trending Precambrian (2.42 Ga) dykes that extend uninterrupted across the Yilgarn Craton. We propose that lithospheric fabrics frozen-in at the time of craton formation (~2.76–2.65 Ga) generated a mechanical weakness which subsequently influenced the orientation and emplacement of the dykes. Further evidence for a similar, ancient (~2.73 Ga) architectural fabric comes from recent isotope geochemistry analysis of primary ENE-trends within the Yilgarn Craton. Overall, these results point toward large-scale, fossilized lithospheric fabric within the Yilgarn Craton, preserved for over two billion years, offering a unique window into the formation and early evolution of the continent.
How to cite: Gauntlett, M., Eakin, C., Bishoyi, N., Zhang, P., O'Donnell, J.-P., Murdie, R., Miller, M., Pickle, R., and Ebrahimi, R.: Seismic anisotropy analysis across Southwestern Australia reveals ENE‐trending lithospheric architecture linked to Archean Yilgarn Craton formation, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-4571, https://doi.org/10.5194/egusphere-egu26-4571, 2026.
Body- and surface-wave seismic data provide complementary sensitivities to the anisotropic elastic structure of the Earth, and the potential constraints of a simultaneous inversion would extend significantly beyond those of the individual phases. However, joint body- and surface-wave anisotropic imaging remains limited, mainly because of the high nonlinearity of the problem and the different inversion methods traditionally adopted for body- and surface-wave phases. Here, we implement a nonlinear transdimensional stochastic solver based on the reversible-jump Markov chain Monte Carlo (RJMCMC) algorithm to simultaneously invert P-, S- and Rayleigh-wave data. By sampling irregularly meshed anisotropic velocity models for the upper mantle, with different mesh configurations and complexities adaptable to the heterogeneous data constraints, we populate an ensemble of variable solutions describing the data within the uncertainties. The method is validated using independent synthetic seismograms simulated with SPECFEM3D Globe in an anisotropic upper mantle plume model. We show how the different sensitivities of the data translate into different constraints on upper mantle seismic structure, and we analyze metrics to quantitatively assess uncertainties in the inferred solutions.
How to cite: Del Piccolo, G., Byrnes, J., Gaherty, J., VanderBeek, B., Faccenda, M., and Morelli, A.: Joint body- and surface-wave probabilistic transdimensional tomography of upper mantle seismic anisotropy, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-13229, https://doi.org/10.5194/egusphere-egu26-13229, 2026.
The 2023 Kahramanmaraş earthquake doublet (Mw 7.8 and Mw 7.7) produced an extensive rupture along several segments of the East Anatolian Faults (EAF), and triggered intense aftershock activity in southeastern Türkiye. This seismic sequence therefore provides an exceptional dataset to investigate the crustal anisotropy in such a complex tectonic area. In this study, we evaluated the crustal anisotropy in the source region of these catastrophic earthquakes by conducting a detailed local S-wave splitting (SWS) analysis on a relocated earthquake catalogue. We have performed shear-wave splitting measurements over several thousand local-S waveforms recordings of 31 permanent broadband seismic stations operated by AFAD (Turkish Earthquake Data Center) that were extracted using precise relocation of aftershock activity. After a visual quality control procedure for each splitting analysis, a total of 486 high-quality measurements were obtained. The results reveal a highly heterogeneous anisotropic pattern, with fast direction oriented from N80°W to N79°E and mean fast direction for the whole dataset of N16°E, reflecting the lateral variations in the regional stress field along the EAF, the Sürgü-Çardak Fault (SÇF), and the Malatya Fault. A transition between stress-induced and structure-related anisotropy is clearly identified across different segments of the EAF. Stations in close proximity to the EAF exhibit a dominant structure-induced anisotropic signature, characterized by the strict alignment of FPDs parallel to the fault geometry. Overall, the obtained results provide a comprehensive perspective on how the upper crust responds to substantial stress release, thus offering critical insights into the mechanical behaviour of complex fault networks where the regional collisional stress regimes and strike-slip faulting systems converge.
How to cite: Erman, C., Baccheschi, P., Yolsal-Çevikbilen, S., Eken, T., and Taymaz, T.: Crustal Anisotropy Variations Revealed by Local S-wave Splitting in the Source Region of 2023 Kahramanmaraş Earthquakes along the East Anatolian Fault Zone, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-12795, https://doi.org/10.5194/egusphere-egu26-12795, 2026.
We constrain the extent and anisotropic properties of the Ivrea Geophysical Body (IGB) beneath the Western Alps using receiver function (RF) analysis of 66 teleseismic datasets. The IGB represents one of the most prominent examples of shallow mantle material within continental crust, yet its geometry, composition, and tectonic significance remain debated beyond its well-known positive gravity anomaly. Using teleseismic waves recorded from temporary seismic deployments and permanent seismic networks across the western Alps, we perform a comprehensive receiver function (RF) analysis that indicates the presence of anisotropic mantle materials at shallow depth, associated with the occurrence of the IGB, in terms of P-to-s converted energy out of the radial plane. We characterise the anisotropic rock volumes solving an inverse problem using a Neighbourhood Algorithm. The results indicate that 35 out of 66 RF data-sets from this study, together with five additional stations from a previous study, display coherent anisotropic characteristics directly above the high-gravity anomaly and can be associated with the IGB. These stations exhibit strong anisotropy (~15%) and a coherent fast-axis pattern that systematically rotates from south to north, following the arcuate geometry of the Alpine trench. The depth distribution of the anisotropic interfaces constrains the IGB as a continuous lithospheric-scale body approximately 170 km long, 30-50 km wide, and 20-45 km thick, with its upper boundary as shallow as 1 km depth. The whole body is slightly dipping towards the East. Seismic velocities and anisotropy magnitudes indicate a dominantly mantle-derived composition, consistent with a peridotitic protolith variably overprinted by serpentinite-rich shear zones. Our results refine the three-dimensional extent of the IGB and demonstrate that its anisotropic fabric records the deformation associated with Alpine subduction, slab rollback, and subsequent exhumation, providing new constraints on the tectonic evolution of the western Alpine lithosphere.
How to cite: Confal, J., Pondrelli, S., Salimbeni, S., and Piana Agostinetti, N.: Mapping the Ivrea Geophysical Body and its anisotropic properties beneath the Western Alps using receiver functions analysis, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-5755, https://doi.org/10.5194/egusphere-egu26-5755, 2026.
The Slave craton in northwest Canada is characterized by thick, cold, depleted lithosphere, and its surface geology includes some of the oldest rocks on the planet. In addition, the central Slave has proven economic importance, with a thriving diamond industry fed by suites of Miocene kimberlites. Previous studies of Slave craton architecture and anisotropy suggested a stratified lithosphere within the central Slave, likely associated with craton formation processes and subsequent metasomatism.
Since the original shear-wave splitting studies carried out in the central Slave craton, new seismograph installations have been carried out which permit an expanded view of the architecture of the craton as a whole, as well as its margins. Here we measure (or remeasure) shear wave splitting parameters for the complete dataset, which spans up to three decades for the longest-running stations. This systematic approach allows for a comprehensive comparison of anisotropic parameters across the craton.
Preliminary results suggest that NE-SW fast-polarization orientations dominate the craton at a large scale, though with significant local variability in the central Slave, suggesting lateral variability in lithospheric properties. We look for azimuthal variations in splitting measurements that may indicate stratified anisotropy, and we compare the results with models of azimuthal anisotropy from recent surface wave tomography studies.
How to cite: Darbyshire, F. and Dave, R.: Seismic anisotropy in the Slave craton, northern Canada: inferences from a new shear-wave splitting compilation, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-3197, https://doi.org/10.5194/egusphere-egu26-3197, 2026.
Slab tears are observed around the globe with increasing frequency as datasets and imaging methodologies improve, though the interactions between slab tears and the surrounding mantle flow remain enigmatic. Constraints on mantle flow around and through slab tears are crucial to a comprehensive understanding of slab-mantle interactions, as (1) cross-tear flow may allow mixing between upper mantle reservoirs otherwise separated by subducting slabs, and (2) cross-tear flow may impact the strength of nearby corner flow and therefore influence regional dynamic topography. However, the ability to study slab tears and their impact on mantle flow is limited by the number of slabs with clearly observed tearing and sufficient measurement density to capture lateral variations in mantle flow across the tear. On both counts, the Colombian Andes serve as an ideal region to study the interplay between slab tears and mantle dynamics.
The Colombian Andes are shaped by complex interactions between the subducting Nazca and Caribbean plates, as most clearly manifested by the Caldas Tear—a sharp lateral offset in slab seismicity near 5.5°N spanning more than 150 km. Using data collected across this boundary during the recent MUSICA (Modeling, Uplift, Seismicity, and Igneous geochemistry of the Colombian Andes) broadband seismic deployment, we investigate lateral variations in seismic anisotropy across the Colombian Andes by measuring shear-wave splitting of SKS and SKKS phases from teleseismic earthquakes.
Measurements of shear-wave splitting offer direct observational constraints on seismic anisotropy. Seismic anisotropy in the upper mantle forms primarily from the deformation-induced alignment of intrinsically anisotropic olivine crystals. Under various ambient stress and hydration conditions, different olivine petrofabrics develop that relate the bulk anisotropic fast direction to the orientation of maximum extensional strain. By inferring petrofabric type, shear-wave splitting measurements can directly constrain the geometry of deformation in the upper mantle and thus provide insight into the impact of complex slab geometry on mantle dynamics.
Our findings detail a complex regional pattern of mantle flow as the result of three interacting flow components: (1) entrained trench-perpendicular corner flow in the mantle wedges above sinking plates, (2) mantle flow through the Caldas Tear, and (3) trench-parallel flow far east of both subducting plates. Measured splitting delay times far exceed those expected from lithospheric anisotropy alone and thus support a deeper anisotropic source. Additionally, we observe strong back azimuthal variations in splitting measurement quality and quantity that demand further investigation. Future work will explore constraining lateral and vertical anisotropic complexity simultaneously using splitting intensity tomography.
How to cite: Carchedi, C., Wagner, L., and Monsalve, G.: Flow through a slab tear? Lateral variations in seismic anisotropy beneath the Colombian Andes, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-1431, https://doi.org/10.5194/egusphere-egu26-1431, 2026.
Abstract
Deformation in northern (NE) Tibet is essential for understanding the geodynamic processes of crustal thickening and outward growth associated with the Indo-Asian collision. We analyze receiver function data recorded by the regional seismic array of ChinArray-Ⅱ and permanent stations of the study region. The crustal thickness and Vp/Vs ratio are estimated using the H–κ grid searching technique (Zhu et al., 2000) . We also perform a joint analysis of Pms from radial and tangential receiver functions to measure fast polarization direction and splitting time (Liu et al., 2012). The harmonic analysis is adopted to obtain reliable crustal azimuthal anisotropy (Sun et al., 2012). Our result shows that the crust is significantly thickened (≥50 km) west of ~103°, while the Vp/Vs ratio is relatively low (~1.73) beneath the Qilian orogeny. We also found measurements of crustal azimuthal anisotropy beneath 71 stations in which the Pms arrivals with a dominant degree-2 back azimuth variations. The crustal anisotropy shows a north-south change across the Longshoushan fault. The measured splitting time in the region south of the Longshoushan fault is 0.22-1.02 s (with an average of 0.46 s). The fast direction mainly along the NW direction is roughly close to the fast polarization from XKS (Chang et al., 2021), which is parallel to the trending of the Qian orogenic belt, indicating a vertically coherent lithospheric deformation beneath the NE Tibet. To the north, the Alxa block exhibits a NNE-NE fast polarization with an average delay time of ~0.47s. Such observation differs from the fast-axis direction of mantle anisotropy, indicating that the crust and lithospheric mantle are decoupled. The north-south variation in crustal anisotropy of our study area may suggest that the growth front of the northeastern Tibetan Plateau may have extended to the Longshoushan fault.
Acknowledgments
Seismic data of the ChinArray was provided by the International Earthquake Science Data Center at Institute of Geophysics, China Earthquake Administration (https://doi.org/10.11998/ IESDC). Seismic waveforms recorded by the permanent stations of the China National Seismic Networks can be downloaded from the National Earthquake Data Center, China Earthquake Administration (https://data.earthquake.cn/) (Zheng et al., 2010). This research was supported by the NSF of China (42030310, 42474133).
References
Zhu, L., & Kanamori, H. 2000. Moho depth variation in southern California from teleseismic receiver functions. J. Geophys. Res., 105(B2), 2969–2980.
Liu H., Niu F., 2012. Estimating crustal seismic anisotropy with a joint analysis of radial and transverse receiver function data. Geophys. J. Int., 188: 144–164.
Sun Y., Niu F., Liu H., et al. 2012. Crustal structure and deformation of the SE Tibetan plateau revealed by receiver function data. Earth Planet. Sci. Lett., 349-350: 186–197.
Chang L., Ding Z., Wang C., 2021. Upper mantle anisotropy and implications beneath the central and western North China and the NE margin of Tibetan Plateau. Chin. J. Geophys. (in Chinese), 64(1):114-130.
How to cite: Zhang, R. and Hua, Y.: Crustal structural and anisotropy in northeastern Tibetan Plateau from receiver functions, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-3264, https://doi.org/10.5194/egusphere-egu26-3264, 2026.
Posters virtual: Thu, 7 May, 14:00–18:00 | vPoster spot 3
EGU26-10489 | ECS | Posters virtual | VPS25
3-D Anisotropic Structure of the Upper Mantle beneath the Iranian Plateau Using SKS Splitting Intensity TomographyThu, 07 May, 15:18–15:21 (CEST) vPoster spot 3
The Iranian plateau, characterized by the Arabia-Eurasia continental collision in the Zagros and the Makran oceanic subduction system, presents a unique opportunity to investigate the underlying processes of lithospheric deformation and upper-mantle dynamics. Previous studies of upper mantle seismic anisotropy, mostly using SK(K)S splitting and occasionally direct S waves revealed complex patterns for the fast axes. The observed rotations of fast axis obtained from S and SK(K)S waves along different tectonic setting, the difference in fast directions between S and SK(K)S phases in central Iran, evidence for two-layer anisotropy, and ambiguity regarding the depth origin of observed anisotropy emphasize the need for further studies. These challenges, together with the pronounced tectonic heterogeneity of the Iranian plateau, call for tomographic approaches that allows for the localization of anisotropic structure. In this study, we utilize SKS splitting intensity tomography to elucidate the depth distribution of the anisotropic properties of the upper mantle beneath the Iranian plateau. Our dataset includes teleseismic events with magnitude above 5.5 and epicentral distances between 90 and 130 degrees recorded by 151 permanent (2015-2021) and 296 temporary seismic stations (2003-2021). We employ a three-dimensional full-wave anisotropy tomography method using splitting intensity, which provides enhanced depth resolution compared to traditional shear wave splitting methods. This method utilizes perturbation theory to establish the linear relationship between splitting intensity and anisotropic parameters, including the azimuth of fast axis and anisotropy strength, and incorporates Green's function databases to efficiently compute the sensitivity or Fréchet kernels. Splitting intensity measurements are inverted to construct a three-dimensional model of upper-mantle azimuthally anisotropic structure beneath the study area. Results show clear lateral differences in anisotropic strength and fast-axis orientation specifically between the Zagros and Alborz regions, as well as the adjacent domains. Vertical profiles illustrate depth-dependent heterogeneous anisotropic structures across the lithosphere–asthenosphere boundary into the asthenospheric upper mantle. These variations likely reflect the combined influence of regional tectonic processes, continental collision, lithospheric deformation, and present-day mantle flow patterns beneath the Iranian plateau. Our results highlight the potential of SKS splitting intensity tomography to resolve complex mantle anisotropy and shed new light on the three-dimensional deformation structure of the upper mantle. The observed lateral and depth variations in anisotropy provide new insights into how the relationship between surface tectonics and upper-mantle deformation varies spatially across major tectonic domains such as the Zagros, Makran, Central Iran, and the Alborz.
How to cite: Arvin, S., Lan, H., Chen, L., Ke, Z., Lin, Y., Zhao, L., and Talebian, M.: 3-D Anisotropic Structure of the Upper Mantle beneath the Iranian Plateau Using SKS Splitting Intensity Tomography, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-10489, https://doi.org/10.5194/egusphere-egu26-10489, 2026.
