Regionalized comparison of global Earth models of seismic velocity, geoid and topography: implications on the geodynamics of ridges and subductions

• Published in: Physics of the earth and planetary interiors 1997, Vol.99 (1), p.91-102
• Main Authors: Perrot, Karine, Tarits, Pascal, Goslin, Jean
• Format: Article
• Language: English
• ISSN: 0031-9201; 1872-7395
• DOI: 10.1016/S0031-9201(96)03179-2

Global Earth models of seismic velocity anomalies and geoid heights have been compared using the non-parametric Spearman rank-order correlation test to analyse their spatial coherence at both global and regional scales. At the global scale, these comparison results are similar to previously published results. This confirms that the assumed linear relationship between the tomographic models and the geoid is valid at the global scale. The comparison between global Earth models was then conducted in two structural provinces — a ‘ridge’ province and a ‘subduction’ province. We observe a positive correlation between tomography and geoid data near the transition zone in the two provinces. A significant positive correlation between the geoid and the topography is observed in the ‘subduction’ province in the L = 7–8 and L = 9–10 wavebands. These positive correlations are consistent with the hypothesis of deep penetration of subducted slabs into the mantle. The correlation in these two wavebands also suggests that the mantle heterogeneities under subduction zones are characterized by wavelengths around 4000 km. In the ‘ridge’ province, the topography and the tomography are negatively correlated in the upper mantle at shorter wavelengths (up to L = 15). This result is in favour of a shallow origin of the ridge material.