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Pure Appl. Geophys. 172 (2015), 26572668 2015 Springer Basel
DOI 10.1007/s00024-015-1039-4 Pure and Applied Geophysics
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Web End = Calculation of Moho Depth by Gravity Anomalies in QinghaiTibet Plateau Based on an Improved Iteration of ParkerOldenburg Inversion
CHONG ZHANG,1 DANIAN HUANG,1 GUOCHAO WU,1 GUOQING MA,1 YUAN YUAN,1 and PING YU1
AbstractA derivative formula for interface inversion using gravity anomalies, combining the ParkerOldenburg method for calculating and inverting gravity anomalies with Xus iteration method for continuing potential elds, leads to a convergent inversion algorithm and an optimally located density interface geometry. In this algorithm, no ltering or any other convergence control techniques are needed during iteration. The method readily iterates the variable depth of the gravity interface by means of upward continuation in a form equivalent to inversion iteration in the Fourier domain instead of the divergent, downward continuation term. This iteration algorithm not only efciently solves the divergence problem in the inversion iteration procedure but also validly obtains an excellent result for the density interface. A numerical example is presented to illustrate perfect execution of this approach in gravity exploration, and a real geophysical example of inversion of the Moho depth by means of this approach using a set of measured gravity anomalies over the QinghaiTibet Plateau in China is offered.
Key words: 3D gravity inversion, density interface, Moho depth, QinghaiTibet Plateau.
1. Introduction
Inversion is a classical and developing technology in geophysical exploration, especially in potential eld prospecting. One wants to know the shape of an underground mass distribution, the geometry of a density interface, or other geological structures by inverting measured gravity or other geophysical anomalies.
There are many kinds of methods for potential eld inversion (MENKE 1984; BLAKELY 1995; ZH
DANOV 2002; GUBBINS 2004, and others), one such
application being calculating the depth of the Moho discontinuity from gravity anomalies. Many approaches have been applied to determine the nature of the Moho topography from associated gravity anomalies. Some researchers (CORDELL and HENDER
SON 1968; BHASKARA RAO and RAMESHBABU 1991)
calculated total gravity anomalies as the sum...