A 2-D spectral-element method for computing spherical-earth seismograms - II. Waves in solid-fluid media
We portray a dedicated spectral-element method to solve the elastodynamic wave equation upon spherically symmetric earth models at the expense of a 2-D domain. Using this method, 3-D wavefields of arbitrary resolution may be computed to obtain Fréchet sensitivity kernels, especially for diffracted a...
| المؤلفون الرئيسيون: | , , |
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| التنسيق: | Journal article |
| اللغة: | English |
| منشور في: |
2008
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| _version_ | 1826289171560398848 |
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| author | Nissen-Meyer, T Fournier, A Dahlen, F |
| author_facet | Nissen-Meyer, T Fournier, A Dahlen, F |
| author_sort | Nissen-Meyer, T |
| collection | OXFORD |
| description | We portray a dedicated spectral-element method to solve the elastodynamic wave equation upon spherically symmetric earth models at the expense of a 2-D domain. Using this method, 3-D wavefields of arbitrary resolution may be computed to obtain Fréchet sensitivity kernels, especially for diffracted arrivals. The meshing process is presented for varying frequencies in terms of its efficiency as measured by the total number of elements, their spacing variations and stability criteria. We assess the mesh quantitatively by defining these numerical parameters in a general non-dimensionalized form such that comparisons to other grid-based methods are straightforward. Efficient-mesh generation for the PREM example and a minimum-messaging domain decomposition and parallelization strategy lay foundations for waveforms up to frequencies of 1 Hz on moderate PC clusters. The discretization of fluid, solid and respective boundary regions is similar to previous spectral-element implementations, save for a fluid potential formulation that incorporates the density, thereby yielding identical boundary terms on fluid and solid sides. We compare the second-order Newmark time extrapolation scheme with a newly implemented fourth-order symplectic scheme and argue in favour of the latter in cases of propagation over many wavelengths due to drastic accuracy improvements. Various validation examples such as full moment-tensor seismograms, wavefield snapshots, and energy conservation illustrate the favourable behaviour and potential of the method. © 2008 The Authors Journal compilation © 2008 RAS. |
| first_indexed | 2024-03-07T02:24:50Z |
| format | Journal article |
| id | oxford-uuid:a53cc4f6-c8fb-439d-b3fd-d83a00dc2340 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T02:24:50Z |
| publishDate | 2008 |
| record_format | dspace |
| spelling | oxford-uuid:a53cc4f6-c8fb-439d-b3fd-d83a00dc23402022-03-27T02:39:04ZA 2-D spectral-element method for computing spherical-earth seismograms - II. Waves in solid-fluid mediaJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:a53cc4f6-c8fb-439d-b3fd-d83a00dc2340EnglishSymplectic Elements at Oxford2008Nissen-Meyer, TFournier, ADahlen, FWe portray a dedicated spectral-element method to solve the elastodynamic wave equation upon spherically symmetric earth models at the expense of a 2-D domain. Using this method, 3-D wavefields of arbitrary resolution may be computed to obtain Fréchet sensitivity kernels, especially for diffracted arrivals. The meshing process is presented for varying frequencies in terms of its efficiency as measured by the total number of elements, their spacing variations and stability criteria. We assess the mesh quantitatively by defining these numerical parameters in a general non-dimensionalized form such that comparisons to other grid-based methods are straightforward. Efficient-mesh generation for the PREM example and a minimum-messaging domain decomposition and parallelization strategy lay foundations for waveforms up to frequencies of 1 Hz on moderate PC clusters. The discretization of fluid, solid and respective boundary regions is similar to previous spectral-element implementations, save for a fluid potential formulation that incorporates the density, thereby yielding identical boundary terms on fluid and solid sides. We compare the second-order Newmark time extrapolation scheme with a newly implemented fourth-order symplectic scheme and argue in favour of the latter in cases of propagation over many wavelengths due to drastic accuracy improvements. Various validation examples such as full moment-tensor seismograms, wavefield snapshots, and energy conservation illustrate the favourable behaviour and potential of the method. © 2008 The Authors Journal compilation © 2008 RAS. |
| spellingShingle | Nissen-Meyer, T Fournier, A Dahlen, F A 2-D spectral-element method for computing spherical-earth seismograms - II. Waves in solid-fluid media |
| title | A 2-D spectral-element method for computing spherical-earth seismograms - II. Waves in solid-fluid media |
| title_full | A 2-D spectral-element method for computing spherical-earth seismograms - II. Waves in solid-fluid media |
| title_fullStr | A 2-D spectral-element method for computing spherical-earth seismograms - II. Waves in solid-fluid media |
| title_full_unstemmed | A 2-D spectral-element method for computing spherical-earth seismograms - II. Waves in solid-fluid media |
| title_short | A 2-D spectral-element method for computing spherical-earth seismograms - II. Waves in solid-fluid media |
| title_sort | 2 d spectral element method for computing spherical earth seismograms ii waves in solid fluid media |
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