000004291 001__ 4291
000004291 005__ 20191113082557.0
000004291 037__ $$aPOSTER-2019-0097
000004291 100__ $$aVan Camp, M.
000004291 245__ $$aComparing global seismic tomography models using the varimax Principal Component Analysis
000004291 260__ $$c2019
000004291 269__ $$c2019-12-10
000004291 520__ $$aClassical analysis of new tomography models consists in a comparison with others by correlation, spectral profiles, or localisation of patterns. To interpret the models in a quantitative, objective way and ease comparisons, we analyse the model information using principal component (PC) analysis. The varimax criterion applied to the PCs separates modes associated with different depth ranges. This enables determining the importance of different parts of the tomography models when reconstructing them. We apply this method to the isotropic part of 6 global shear-wave speed models: SAVANI (Auer et al., 2014), S20RTS (Ritsema et al., 1999), S40RTS (Ritsema et al., 2011), SEMUCB-WM1 (French & Romanowicz, 2014), SGLOBE-rani (Chang et al., 2015), and S362WMANI+M (Moulik & Ekstrom, 2014). According to the models, the method generates 7 to 15 independent varimax PCs, capturing more than 97% of the total information. A comparison of the PCs with the information extracted from the full models shows that no interpretable information is lost. Each mode is composed of a vertical anomaly profile, to which we associate a horizontal pattern by orthogonal projection. The maximum of the depth profile and the geographical distribution of the horizontal pattern enable examining the key characteristics of the main components of the models. For a fair comparison, we also compute a varimax PCA on a concatenation of the 6 models together. This imposes a projection of the average vertical profile, which allows for a mode-by-mode comparison between the model set. Similar main regions are identified when applying the analysis either to the individual tomography models or to the concatenation of the models: (i) Large Low Shear Velocity Provinces (LLSVPs); (ii) Mid-lower mantle (~1,200 km depth) showing some deep subduction signals and low-velocity anomalies beneath the Pacific and Africa, possibly associated with mantle plumes; (iii) Uppermost lower mantle (~800 km depth), also with deep subduction and low-velocity in the southeastern Pacific ocean; (iv) Transition zone (~400 km depth), showing subduction and low velocity anomalies beneath the Pacific and Indian oceans; and, (v) ridges and cratons in the uppermost upper mantle (~200 km depth). We discuss the significance and potential implications of these main regions that are identified.
000004291 594__ $$aNO
000004291 6531_ $$aGlobal seismic tomography
000004291 6531_ $$aComparing models
000004291 6531_ $$aPCA
000004291 6531_ $$aVarimax
000004291 700__ $$ade Viron, O.
000004291 700__ $$aFerreira, A.M.G.
000004291 773__ $$tAGU Fall meeting 2019
000004291 8560_ $$fmichel.vancamp@observatoire.be
000004291 980__ $$aCPOSTER