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

ABSTRACT

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 $\mathit{\delta }{T}_{\mathit{zzz}}^{\mathrm{res}}$ 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 $\mathit{\delta }{T}_{\mathit{zzz}}^{\mathrm{res}}$ 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 $\mathit{\delta }{T}^{\mathrm{res}}$, disturbing radial gravity vector $\mathit{\delta }{T}_z^{\mathrm{res}}$, and disturbing radial-radial gravity gradient tensor $\mathit{\delta }{T}_{\mathit{zz}}^{\mathrm{res}}$), especially for the Qaidam, Sichuan, Tarim, and Turpan basins. Numerical results over the Himalayan region demonstrate that the GC component $\mathit{\delta }{T}_z^{\mathrm{res}}$ 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.

KEYWORDS:

• Gravity field
• gravitational curvatures
• tesseroid
• gravitational stripping correction
• Moho

Acknowledgments

We are very grateful to Prof. P. Holota, Prof. Roman Pasteka, and two anonymous reviewers for their valuable comments and suggestions, which greatly improved the manuscript. This study is supported by National Natural Science Foundation of China [Grant Nos. 42030105, 41721003, 41804012, 41631072, 41874023].

Disclosure statement

No potential conflict of interest was reported by the authors.

Data availability statement

The data that support the findings of this study are available from the corresponding author on reasonable request.

Correction Statement

This article has been corrected with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

 This study is supported by National Natural Science Foundation of China [Grant Nos. 42030105, 41721003, 41804012, 41631072, 41874023].

Notes on contributors

Xiao-Le Deng

Xiao-Le Deng received his PhD degree from Wuhan University in 2019. His current research mainly focuses on applications of gravity and magnetic field modeling (e.g., gravitational curvatures and magnetic curvatures) in geoscience.

Wen-Bin Shen

Wen-Bin Shen is the head and professor of Department of Geophysics, School of Geodesy and Geomatics, Wuhan University. He received his PhD degree from Graz Technical University in Austria in 1996. He holds memberships of IAG, EGU, AGU, and IUGG. His research interests focus on relativistic geodesy, Earth rotation and global change, and Earth’s free oscillation.

Michael Kuhn

Michael Kuhn is the Associate Professor of the School of Earth and Planetary Sciences, Curtin University.

Christian Hirt

Christian Hirt received his PhD degree from the University of Hannover in Germany in 2001. His research interests are modern geodesy, gravity field modeling and determination, geodetic astronomy, and atmospheric refraction.

Roland Pail

Roland Pail is the Professor of the Institute for Astronomical and Physical Geodesy, Technical University of Munich. He received his PhD degree from Graz Technical University in Austria in 1999. His research interests are physical geodesy, satellite geodesy, global and regional Earth gravity field modeling, calibration/validation of satellite observations, future gravity missions, mass transport processes in the Earth system, and synthetic Earth models.