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Inference from noisy data with an unknown number of discontinuities: ideas from outside the box


Sambridge, M and Bodin, T and Reading, AM and Gallagher, K, Inference from noisy data with an unknown number of discontinuities: ideas from outside the box, Preview Journal, Number 147: ASEG 2010 Geophysical Conference Proceedings, 22-26 August 2010, Sydney, Australia, pp. 1-5. ISSN 1836-084X (2010) [Refereed Conference Paper]

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Copyright 2010 ASEG

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DOI: doi:10.1071/ASEG2010ab044


information from complex datasets in situations where direct measurement is not possible. Such inverse problems are ubiquitous across the physical and mathematical sciences and are central to discovery of resources within the Earth upon which Australian society is dependent. A recurring problem is how to choose the number of unknowns with which to fit data. If too few are chosen the data cannot be fit and if too many the inversion results become unreliable and contain unwarranted detail. Statistical methods are often used to find optimal numbers of unknowns, but these are based on simplistic assumptions and require multiple trial inversions to be performed with different numbers of variables. A new general approach recently applied to geophysical problems is to ask the data itself `How many unknowns should be used ? While this may seem counter-intuitive at first sight it turns out to be entirely feasible. In effect the number of unknowns itself becomes an unknown. An extension of the basic approach also allows the level of noise on the data to also be included as an unknown. In this presentation we outline the central ideas, and illustrated through an example where a geophysical property varies only in 1-D (usually depth or time) and is constrained from surface measurements. Applications of the general approach are to airborne EM data, borehole geophysics, seismic interpretation and also palaeoclimate reconstructions.

Item Details

Item Type:Refereed Conference Paper
Keywords:Geophysical inversion methods, disocontinuous fields, seismic, wireline, AEM
Research Division:Earth Sciences
Research Group:Geophysics
Research Field:Geophysics not elsewhere classified
Objective Division:Mineral Resources (Excl. Energy Resources)
Objective Group:Mineral exploration
Objective Field:Mineral exploration not elsewhere classified
UTAS Author:Reading, AM (Professor Anya Reading)
ID Code:78405
Year Published:2010
Deposited By:Earth Sciences
Deposited On:2012-06-26
Last Modified:2012-11-14

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