New analytic solutions for modeling vertical gravity gradient anomalies. (7th May 2016)

• Record Type: Journal Article
• Authors: Kim, Seung‐Sep; Wessel, Paul
• Is Part Of: Geochemistry, geophysics, geosystems. Volume 17:Number 5(2016:May)
• Page Start: 1915
• Page End: 1924
• Publication Date: 2016-05-07
• Subjects: vertical gravity gradient -- potential theory -- satellite‐derived gravity; Geochemistry -- Periodicals; Geophysics -- Periodicals; Earth sciences -- Periodicals; 550.5
• DOI: 10.1002/2016GC006263
• Languages: English
• ISSNs: 1525-2027

Abstract

Abstract: Modern processing of satellite altimetry for use in marine gravimetry involves computing the along‐track slopes of observed sea‐surface heights, projecting them into east‐west and north‐south deflection of the vertical grids, and using Laplace's equation to algebraically obtain a grid of the vertical gravity gradient (VGG). The VGG grid is then integrated via overlapping, flat Earth Fourier transforms to yield a free‐air anomaly grid. Because of this integration and associated edge effects, the VGG grid retains more short‐wavelength information (e.g., fracture zone and seamount signatures) that is of particular importance for plate tectonic investigations. While modeling of gravity anomalies over arbitrary bodies has long been a standard undertaking, similar modeling of VGG anomalies over oceanic features is not commonplace yet. Here we derive analytic solutions for VGG anomalies over simple bodies and arbitrary 2‐D and 3‐D sources. We demonstrate their usability in determining mass excess and deficiency across the Mendocino fracture zone (a 2‐D feature) and find the best bulk density estimate for Jasper seamount (a 3‐D feature). The methodologies used herein are implemented in the Generic Mapping Tools, available from gmt.soest.hawaii.edu . Key Points: New analytic solutions for vertical gravity gradient anomalies over simple bodies New analytic solutions for vertical gravity gradient anomalies over arbitrary 2‐D and 3‐D sources