Method for gravity-seismic joint inversion density interface distribution under spherical coordinate system

Abstract

The invention provides a method for gravity-seismic joint inversion density interface distribution under a spherical coordinate system. The method comprises the steps of estimating an initial densityinterface depth, calculating a gravity anomaly matrix value after iteration of a corrected density interface depth, calculating a difference value [delta]hi between a known seismic constraint point and an inversion calculation point, carrying out the root-mean-square error analysis, and performing multi-iteration calculation and iteration end point judgment. The method has the beneficial effects that for regional large-scale density interface inversion research, the earth is approximated to be a sphere, a conventional prismoid is replaced with a sphere unit body, the problem that the earth curvature is ignored in large-scale research is solved, and the inversion result is closer to the real situation. Meanwhile, a depth weighting factor and seismic constraints are introduced in the inversion process, so that the inversion precision is improved, and the multiplicity and uncertainty of density interface inversion are reduced.

Description

technical field [0001] The invention belongs to the technical field of geophysical exploration, and in particular relates to a method for joint inversion of density interface distribution by heavy earthquakes in a spherical coordinate system. Background technique [0002] In the field of geophysical exploration, density interface inversion is of great significance in inferring regional structure research, obtaining crystalline basement and Moho surface relief, etc. Density interface inversion refers to the inversion of the density interface depth according to the anomalous change of gravity. At present, there are many inversion methods for interface depth, which can be roughly divided into space domain and frequency domain methods. The space domain mainly includes the direct iterative method, the compressed surface method and the nonlinear inversion method. The space domain inversion interface generally has discontinuity and the calculation speed is slow; the frequency doma...

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Problems solved by technology

[0004] In order to make up for the deficiencies of the prior art, the present invention provides a method for joint inversion of density interface distribution in a spherical coordinate system. This method is aimed at the study of regional large-scale density interface inversion, and the earth is approximated as a sphere. The spherical unit replaces the conventional prism, which overcomes the problem of ignoring the curvature of the earth in large-scale research, and the inversion results are closer to the real situation. At the same time, depth weighting factors and seismic constraints are introduced in the inversion process, which improves the inversion accuracy and reduces Multiple Solutions and Uncertainty in Density Interface Inversion

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