Geodetic inversion for spatial distribution of slip under smoothness, discontinuity, and sparsity constraints

Ryoko Nakata, Tatsu Kuwatani, Masato Okada, Takane Hori

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)

Abstract

In geodetic data inversion, insufficient observational data and smoothness constraints for model parameters make it difficult to clearly resolve small-scale heterogeneous structures with discontinuous boundaries. We therefore developed a novel regularization scheme for the inversion problem that uses discontinuity, sparsity, and smoothness constraints. In order to assess its usefulness and applicability, the proposed method was applied to synthetic displacements calculated by a ring-shaped and sharply varying afterslip distribution on a plate interface. The afterslip was obtained from reasonable numerical simulation of earthquake generation cycle with a rate- and state- dependent friction law and realistic three-dimensional plate geometry. The obtained afterslip distribution was heterogeneous, and the discontinuous boundary was sharper than that obtained by using smoothness constraint only. The same inversion test was conducted with a smoothly varying circular slip distribution with large slips inside the ring-shaped distribution. The method accurately reproduces the smooth distribution of the slip area as well as the ring-shaped distribution. Therefore, the method could be applied to any slip distribution, with both discontinuous and continuous boundaries. Adopting this method for measured data will make it possible to obtain detailed heterogeneous distributions of physical structures on fault planes. The proposed method is therefore applicable to various geophysical inversion problems that exhibit discontinuous heterogeneity.

Original languageEnglish
Article number20
Journalearth, planets and space
Volume68
Issue number1
DOIs
Publication statusPublished - 2016 Dec 1
Externally publishedYes

Keywords

  • Discontinuous constraint
  • Geodetic inversion
  • Regularized optimization
  • Smoothness constraint
  • Sparsity constraint

ASJC Scopus subject areas

  • Geology
  • Space and Planetary Science

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