Details of the Abstract
| Title of paper | Evaluation of uncertainty in forward modeling of geomagnetic observatory tippers for continental-scale 3-D resistivity structure models beneath China |
| List of authors | X. Tang, K. Baba, Z. Y. Ren |
| Affiliation(s) |
Central South University, Earthquake Research Institute The University of Tokyo, Central South University |
| Summary |
Comprehensively understanding China's geological structure proves challenging due to the intricate nature of its tectonic features. Our research on continental-scale 3-D resistivity structure models aims to provide insights into the properties of the crust and upper mantle, and the evolution of geological structures. A decade-long time series of minute means from three components of the geomagnetic field from 59 mid-latitude geomagnetic observatories was collected and then analyzed. The accuracy in the forward calculation of MT tippers is crucial to obtaining a reliable three-dimensional conductivity model by inversion. In this study, we use a simple method to evaluate the uncertainty of MT tippers’ forward modeling for continental-scale 3-D resistivity structure models in a Cartesian coordinate system. The method is based on the idea that the horizontal coordinate system can be selected arbitrarily for a general 3-D structure. This study focuses on the random component of the uncertainty of forward modeling to an initial 3-D structure model that consists of a homogeneous earth and ocean surrounding the study area. By synthesizing MT tippers’ responses to the model in several different coordinate systems, we can compute the mean, standard deviation, and coefficient of variation. Additionally, we compare the traditional root-mean-square (RMS) with a new RMS in which the residuals are normalized by both the standard errors of the MT tippers’ responses observed and synthesized. Further application in inversion analysis involves evaluating the residuals with normalization by standard errors for both observations and forward calculations to avoid overfitting the program. |
| Session Keyword | 2.0 EM theory, modelling and Inversion |
| File upload |
2.0_evaluation_of_uncertainty_tang_01.pdf
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