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Markov chain Monte Carlo inversion for the rheology of olivine single crystals
Author(s) -
Mullet Benjamin G.,
Korenaga Jun,
Karato ShunIchiro
Publication year - 2015
Publication title -
journal of geophysical research: solid earth
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.983
H-Index - 232
eISSN - 2169-9356
pISSN - 2169-9313
DOI - 10.1002/2014jb011845
Subject(s) - markov chain monte carlo , inversion (geology) , monte carlo method , statistical physics , conjugate gradient method , scaling , covariance , rheology , algorithm , computer science , mathematics , geology , physics , statistics , thermodynamics , geometry , paleontology , structural basin
We present major modifications to the Markov chain Monte Carlo inversion method of Korenaga and Karato (2008), which was developed to analyze rock deformation data and determine a corresponding flow law and its uncertainty. The uncertainties of state variables, e.g., temperature, pressure, and stress, are now taken into account by data randomization, to avoid parameter bias that could be introduced by the original implementation of the cost function. Also, it is now possible to handle a flow law composed of both parallel and sequential deformation mechanisms, by using conjugate gradient search to determine scaling constants. We test the new inversion algorithm extensively using synthetic data as well as the high‐quality experimental data of Bai et al. (1991) on the deformation of olivine single crystals. Our reanalysis of this experimental data set reveals that a commonly adopted value for the stress exponent (∼3.5) is considerably less certain than previously reported, and we offer a detailed account for the validity of our new estimates. The significance of fully reporting parameter uncertainties including covariance is also discussed with a worked example on flow law prediction under geological conditions.