Sensing the global CRUST1.0 Moho by gravitational curvatures of crustal mass anomalies

The gravitational curvatures (GC, the third-order derivatives of the gravitational potential) in gravity field modeling are gaining increased interest in geosciences. The crustal effects of the GC and Moho variation sensed by the GC are not fully evaluated for the current study. In this contribution, the effects of the GC induced by topographic and anomalous crustal masses are investigated based on ETOPO1 and CRUST1.0 models using the tesseroids. By adopting the gravitational stripping correction, the residual GC sensed by the CRUST1.0 Moho depths are presented globally to examine whether the GC can sense crustal mass anomalies at the satellite altitude of 260 km . The spatial analysis using the Pearson correlations coefficient (PCC) between the residual GC and the CRUST1.0 Moho depths is performed. Among the 10 residual GC functionals, the PCC value of the residual radial-radial-radial component delta T-zzz(res) is largest with 0.31, where this value is highly dependent on the spectral content removed from the EGM2008, e.g. signals assumed to relate to deeper mass anomalies. Numerical experiments show that with the increased order of the derivatives up to third-order, the fineness level of different global Moho sensed crustal mass anomalies increases correspondingly. Taking the Tibetan plateau for example, the values of the delta T-zzz(res) can better reveal the detailed features of the Tibetan plateau's Moho depth than these of the lower-order residual radial functionals (i.e. disturbing potential delta T-res, disturbing radial gravity vector delta T-z(res) , and disturbing radial-radial gravity gradient tensor delta T-zz(res) ), especially for the Qaidam, Sichuan, Tarim, and Turpan basins. Numerical results over the Himalayan region demonstrate that the GC component delta T-z(res) has some potential in geophysical inversion. These residual GC functionals would help to get a better knowledge of the internal structures of the Earth and other planetary objects.