SphGLLTools: A toolbox for visualization of large seismic model files based on 3D spectral-element meshes

Caio Ciardelli, Ebru Bozdaǧ, Daniel Peter, Suzan van der Lee

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


Adjoint tomography, a full-waveform inversion technique based on 3D wave simulations, has become a commonly used tool in passive-source seismology, drawing on advances in computational power and numerical methods. From global to reservoir scales, seismic models can iteratively be updated in adjoint inversions by extracting information from full seismic waveforms. Seismic models are typically constructed on the numerical mesh used for wave simulations. Thus the size of model files depends on the minimum resolvable period achieved in simulations controlled by the numerical mesh (the higher the mesh resolution, the larger the model and mesh files). This is specifically a concern for recent global-scale adjoint tomographic models where the size and format of numerical meshes pose challenges for model visualization, analysis, interpretation, and sharing model files. Here, we present SphGLLTools, an open-source toolbox that intends to diminish these challenges by expanding global adjoint models onto spherical harmonic functions, which are widely used in global seismology. Our tools are initially designed for spectral-element meshes used in recent global adjoint tomography studies. SphGLLTools facilitate many commonplace tasks for model visualization and analysis, including spherical harmonic expansion of models sampled on spectral-element meshes together with associated tools for easy sharing, visualization, and interpretation of large-scale seismic model files. All the developed routines are accompanied by user instructions and are available through GitHub. For transparency, reproducibility, and educational purposes, we also include Colab notebooks, which provide an intuitive and comprehensive review of the principles and methods for spectral-element meshes, spherical harmonic expansion, and other model analysis tools.
Original languageEnglish (US)
Pages (from-to)105007
JournalComputers & Geosciences
StatePublished - Dec 2021

Bibliographical note

KAUST Repository Item: Exported on 2021-12-16
Acknowledgements: We thank editor Dario Grana, Bernhard Schuberth, Carl Tape and an anonymous reviewer for constructive feedback which greatly improved the manuscript. We gratefully acknowledge the discussions with Jeroen Tromp on the spherical harmonic expansion of global tomographic models sampled on spectral-element meshes. We thank FAPESP (Grants: 2016/03120-5, 2018/04918-6, and 2018/04917-0) for providing financial support for this research. This research was supported in part through the computational resources and staff contributions provided for the Quest high-performance computing facility at Northwestern University, which is jointly supported by the Office of the Provost, the Office for Research, and Northwestern University Information Technology. EB is supported by her NSF-CAREER project with grant number 1945565. The SphGLLTools toolbox, including the documentation and the examples, is available at https://github.com/caiociardelli/sphglltools.git. The open source spectral-element software package SPECFEM3D_GLOBE is freely available via the Computational Infrastructure for Geodynamics (CIG; ).

ASJC Scopus subject areas

  • Computers in Earth Sciences
  • Information Systems


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