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| A new approach for separating mixed model parameters: application to simultaneous inversion of earthquake source parameters |
| Weijian Mao1,2 |
1 Center for Computational and Exploration Geophysics, Institute of Geodesy and Geophysics, Chinese Academy of Sciences, Wuhan 430077, China
2 State Key Laboratory of Geodesy and Earth’s Dynamics, Institute of Geodesy and Geophysics, Chinese Academy of Sciences, Wuhan 430077, China |
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Abstract A method for simultaneous determination of mixed model parameters, which have different physical dimensions or different responses to data, is presented. Mixed parameter estimation from observed data within a single model space shows instabilities and trade-offs of the solutions. We separate the model space into N-subspaces based on their physical properties or computational convenience and solve the N-subspaces systems by damped least-squares and singular-value decomposition. Since the condition number of each subsystem is smaller than that of the single global system, the approach can greatly increase the stability of the inversion. We also introduce different damping factors into the subsystems to reduce the tradeoffs between the different parameters. The damping factors depend on the conditioning of the subsystems and may be adequately chosen in a range from 0.1 % to 10 % of the largest singular value. We illustrate the method with an example of simultaneous determination of source history, source geometry, and hypocentral location from regional seismograms, although it is applicable to any geophysical inversion.
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Received: 07 August 2013
Published: 10 December 2013
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| Fund:Innovation Project of Chinese Academy of Sciences |
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Corresponding Authors:
Weijian Mao
E-mail: wjmao@whigg.ac.cn
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