Transdimensional Bayesian Attenuation Tomography of the Upper Inner Core

• Published in: Journal of geophysical research. Solid earth 2019-02, Vol.124 (2), p.1929-1943
• Main Authors: Pejić, Tanja, Hawkins, Rhys, Sambridge, Malcolm, Tkalčić, Hrvoje
• Format: Article
• Language: English
• Subjects: Accuracy; Anomalies; Attenuation; Bayesian analysis; Geophysics; inner core; inverse theory; Linearization; Mathematical models; Probability theory; Tomography; Weight
• ISSN: 2169-9313; 2169-9356
• DOI: 10.1029/2018JB016400

Following the linearized attenuation tomography from our previous study (Pejić et al., 2017, https://doi.org/10.1002/2016JB013692), we perform hierarchical transdimensional Bayesian tomography of the upper ≈400 km of the inner core, using 398 globally distributed t∗ estimates. The results are in good agreement with the ones obtained through linearized tomography: they show more complex attenuation pattern than the purely hemispherical one, and the noise estimated from the hierarchical inversion is in good agreement with estimates obtained from the Discrepancy Principle in the previous study. The attenuation pattern we observe gives more weight to the geodynamical models that couple the thermal anomalies of the lowermost mantle to the inner core boundary. Key Points Transdimensional sampling of Voronoi cells on a spherical surface applied to a problem in global tomography No hemispherical pattern is observed in attenuation structure of the upper inner core The study provides a strong seismological hint for a strongly attenuating inner core