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Abstract
We have developed an inversion method for recovery of the geometry of an arbitrary number of geologic units using a regularized leastsquares framework. The method addresses cases in which each geologic unit can be modeled using a constant physical property. Each geologic unit or group assigned the same physical property value is modeled using the signed distance to its interface with other units. We invert for this quantity and recover the location of interfaces between units using the levelset method. We formulate and solve the inverse problem in a leastsquares sense by inverting for such signed distances. The sensitivity matrix to perturbations of the interfaces is obtained using the chain rule, and model mapping from the signed distance is used to recover the physical properties. Exploiting the flexibility of the framework that we develop allows any number of rock units to be considered. In addition, it allows the design and use of regularization incorporating prior information to encourage specific features in the inverted model. We apply this general inversion approach to gravity data favoring minimum adjustments of the interfaces between rock units to fit the data. The method is first tested using noisy synthetic data generated for a model compoed of six distinct units, and several scenarios are investigated. It is then applied to field data from the Yerrida Basin (Australia) where we investigate the geometry of a prospective greenstone belt. The synthetic example demonstrates the proof of concept of the proposed methodology, whereas the field application provides insights into, and potential reinterpretation of, the tectonic setting of the area.
Original language  English 

Pages (fromto)  R623R637 
Number of pages  15 
Journal  Geophysics 
Volume  86 
Issue number  4 
DOIs  
Publication status  Published  20 Jul 2021 
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Dive into the research topics of 'Generalization of levelset inversion to an arbitrary number of geologic units in a regularized leastsquares framework'. Together they form a unique fingerprint.Projects
 2 Finished

Optimising the use of geophysical data for modelling the Australian crust
1/01/19 → 13/06/21
Project: Research

Enabling 3D stochastic geological modelling
Jessell, M., Lindsay, M., Aillères, L. & Armit, R.
1/01/18 → 12/11/21
Project: Research